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Plant growth-promoting rhizobacteria (PGPR) in Cannabis sativa ‘Finola’ cultivation: An alternative fertilization strategy to improve plant growth and quality characteristics
... For example, applications of biocontrol agents that include endophytic species externally to the root system have been shown to enhance growth and reduce pathogen development on cannabis plants [8,22]. Similarly, applications of multiple formulations of bacterial and fungal species to growing substrates have improved the growth and yield of cannabis plants [28,34,[48][49][50] (Tables 2 and 3), confirming what is reported in many other plant species [23,[51][52][53]. These studies point to the benefits provided by certain groups of endophytes when applied to the root zone on promoting cannabis growth. ...
... Significantly increased the plant height (11.5%), plant stalk diameter (42%), and plant biomass at harvest (~120%) of field cannabis plants Plant fitness promotion and biological control [49] Azospirillum brasilense, Gluconacetobacter diazotrophicus, Burkholderia ambifaria, and Herbaspirillum seropedicae Consortium significantly increased the stem length (17%), stem dry weight (63%), leaf dry weight (49%), THC (9%), CBN (18%), and CBD (9%) of greenhouse hemp plants Nitrogen fixation, siderophore production, mineral solubilization, and growth hormone production [49] ...
... Significantly increased the plant height (11.5%), plant stalk diameter (42%), and plant biomass at harvest (~120%) of field cannabis plants Plant fitness promotion and biological control [49] Azospirillum brasilense, Gluconacetobacter diazotrophicus, Burkholderia ambifaria, and Herbaspirillum seropedicae Consortium significantly increased the stem length (17%), stem dry weight (63%), leaf dry weight (49%), THC (9%), CBN (18%), and CBD (9%) of greenhouse hemp plants Nitrogen fixation, siderophore production, mineral solubilization, and growth hormone production [49] ...
The roles of endophytes in Cannabis sativa (cannabis, hemp) remain poorly explored. While in vitro studies suggest that there can be several benefits, such as plant growth promotion and protection against pathogens, more in planta studies are needed. This review summarizes the bacterial and fungal endophytes previously reported in tissues of C. sativa and discusses the factors influencing their presence, as well as their potential beneficial and detrimental effects. Using genome sequencing and culture-based approaches, we describe the microbial diversity in hydroponically cultivated cannabis plants at several developmental stages. These include mother plants, cuttings, vegetative and flowering plants, and tissue-cultured plantlets. Microbes that were present include fungal, yeast, and bacterial endophytes found in roots, stems, leaves, inflorescences, and seeds. These may have originated from the growing substrate or be transmitted through vegetative propagation. Notable endophytes included Rhizophagus irregularis (a mycorrhizal fungus), Penicillium chrysogenum (an antibiotic producer), and various endophytic yeast species not previously described in C. sativa. Endophytes representing potential plant pathogens, such as Fusarium oxysporum, are also present within cannabis tissues, which can negatively impact plant health. Using scanning electron microscopy, we observed that fungal propagules are present within pith parenchyma cells and xylem vessel elements in stem tissues, illustrating for the first time the in situ localization and distribution of endophytes in cannabis vascular tissues. The mechanism of spread through xylem vessels likely contributes to the spread of endophytes within cannabis and hemp plants. Further research is required to validate the roles of endophytes in cannabis and hemp plants grown under commercial production conditions.
... A consortium of four plant-growth promoting rhizobacteria (PGPR), including Azospirillum brasilense, Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae and Burkholderia ambifaria, was used to inoculate seeds from a hemp cultivar (Pagnani et al. 2018). The authors observed that the inflorescences of plants treated with the PGPR consortium presented levels of CBD, THC and CBN higher than the non-inoculated plants ( Table 4). ...
... The authors observed that the inflorescences of plants treated with the PGPR consortium presented levels of CBD, THC and CBN higher than the non-inoculated plants ( Table 4). The seed inoculation with the consortium also showed ability in increasing the accumulation of phenolic compounds (Pagnani et al. 2018) (Table 4). An increase in the cannabinoid content was observed also when PGPR were used as soil amendment on an intermediate-type cultivar (Lyu et al. 2023). ...
... At this stage, an increase in the total terpene content was instead observed in plants treated with the Mucilaginibacter and the Pseudomonas spp., with the highest increase observed for b-caryophyllene (Lyu et al. 2023) (Table 4). Both studies revealed that early inoculation with PGPR also promoted the plant growth and biomass accumulation (Pagnani et al. 2018;Lyu et al. 2023) (Table 4), which was likely related to increased nutrient availability, since PGPR may facilitate access to nutrients (Taghinasab and Jabaji 2020). ...
Cannabis sativa L. is an annual dioecious species native from Central Asia, which has mainly been used for medical purposes by many ancient cultures and is currently used for the treatment of several diseases. The pharmacological properties of C. sativa are related to cannabinoids, a class of secondary metabolites entirely unique to this crop that are produced and stored at high levels in the inflorescences and leaves. In addition to cannabinoids, C. sativa plants also produce a large number of non-cannabinoid secondary metabolites including terpenes, phenolic compounds and others, which have also been associated with health-promoting activities. In recent decades, the interest in secondary metabolites from C. sativa has been increasing due to their potential applications not only as pharmaceuticals, but also as nutraceuticals, food additives, drugs, fragrances, and biopesticides. This has generated a significant increase in the development of effective strategies for improving the production of such bioactive compounds. In this context, elicitation has emerged as an effective tool based on the application of abiotic or biotic factors that induce physiological changes and stimulate defense or stress-related responses in plants, including the biosynthesis of secondary metabolites. The current review gives a comprehensive overview of the available studies on the different elicitation approaches used to enhance the accumulation of the major bioactive compounds in C. sativa, and highlights challenges and opportunities related to the use of external elicitors for improving the added value of this crop.
... Imran et al. (2022) reported the use of plating bacterial count and confocal laser scanning microscopy combined with fluorescence in situ hybridization for the assessment of viable bacteria in the plant rhizobacteria. Similarly, Pagnani et al. (2018Pagnani et al. ( , 2020 used scanning electron microcopy to attest bacterial root colonization by scanning electrons in hemp and wheat cultivation, respectively (Fig. 17.9). ...
... A very interesting and novel study of plant biofertilization of Finola hemp (Cannabis sativa cv. Finola), a lowpsychoactive industrial hemp for use with medicinal purposes, was reported by Pagnani et al. (2018). A rhizobacterial multi-genera consortium was used as the inoculant, and plants were grown without the use of chemical fertilizers. ...
... In another work, Bokszczanin et al. (2021) concluded that in apple cultivation, the use of rhizobacteria with a 50% reduction in the N dose provided the same nutritional quality as the fully fertilized control, with the highest K content. Remarkably, Pagnani et al. (2018) studied the effect of rhizobacterial consortium in the cultivation of industrial hemp "Finola" without the use of chemical fertilizers, reporting not only an increase in bioactive compounds but also preserving the plant growth of the fully fertilized treatment. ...
Considering the global demand for food crops and the adverse effects of the indiscriminate use of agrochemicals in current agriculture, the use of rhizospheric bacterial strains as biofertilizers emerges as a promising strategy to produce food crops in a sustainable manner. A variety of rhizobacterial microorganisms have desirable characteristics that can foster plant growth and nutrient enhancement in the harvested agro-products. Different biofertilization mechanisms are used by microorganisms in their interaction with the plant, such as mineral solubilization, the production of phytohormones and siderophores, and other secondary metabolites and enzymes. On the other hand, through the synthesis of organic compounds, beneficial rhizobacteria can not only favor the growth of the plant but also exert a protective activity against pathogens (biocontrol) and induce the plant’s resistance toward abiotic factors that affect its development. Furthermore, there is a growing interest in researching the impact of biofertilization on crop growth and yield, as well as nutritional quality and the production of bioactive compounds in harvested products. This review emphasizes the relevance of rhizobacteria used as biofertilizers in crop development and productivity, considering the effect of the bacterial inoculants on the alteration of the rhizosphere microbiome’s composition and diversity, the biofertilization mechanisms, and the induction of the plant’s resistance to biotic and abiotic stresses. The emphasis of this review was directed toward in vivo studies focusing on seedlings, plants, and final crop products that attest to the applicability of crop biofertilization as a sustainable alternative to face the current global agricultural challenges.
... Microbial inoculants affect plant growth and development through direct and indirect mechanisms. Such mechanisms may include atmospheric nitrogen fixation and mineral solubilisation, particularly phosphorus (P) containing minerals (Pagnani et al., 2018) that improve nutrient availability and uptake (Tshewang et al., 2020); the production of plant growth-promoting substances or phytohormones (such as auxin, cytokinin, gibberellin, etc.) (Pagnani et al., 2018) that enhance root development (Lyu et al., 2022) and root exudation (Tshewang et al., 2020); and the synthesis of many antagonist chemicals (Pérez-Montaño et al., 2014) that have defensive roles against many plant pathogens (Tshewang et al., 2020). A microbial consortium inoculant that benefits crop yield when applied alone can be combined with rock mineral fertiliser in nutrient-poor soil to get more advantage, as microorganisms increase the dissolution of phosphate-contained minerals that enhance P uptake in many crops, including maize, wheat and sorghum (Kaur and Reddy, 2015;Singh and Reddy, 2011). ...
... Microbial inoculants affect plant growth and development through direct and indirect mechanisms. Such mechanisms may include atmospheric nitrogen fixation and mineral solubilisation, particularly phosphorus (P) containing minerals (Pagnani et al., 2018) that improve nutrient availability and uptake (Tshewang et al., 2020); the production of plant growth-promoting substances or phytohormones (such as auxin, cytokinin, gibberellin, etc.) (Pagnani et al., 2018) that enhance root development (Lyu et al., 2022) and root exudation (Tshewang et al., 2020); and the synthesis of many antagonist chemicals (Pérez-Montaño et al., 2014) that have defensive roles against many plant pathogens (Tshewang et al., 2020). A microbial consortium inoculant that benefits crop yield when applied alone can be combined with rock mineral fertiliser in nutrient-poor soil to get more advantage, as microorganisms increase the dissolution of phosphate-contained minerals that enhance P uptake in many crops, including maize, wheat and sorghum (Kaur and Reddy, 2015;Singh and Reddy, 2011). ...
... A microbial consortium inoculant that benefits crop yield when applied alone can be combined with rock mineral fertiliser in nutrient-poor soil to get more advantage, as microorganisms increase the dissolution of phosphate-contained minerals that enhance P uptake in many crops, including maize, wheat and sorghum (Kaur and Reddy, 2015;Singh and Reddy, 2011). Thus, microbial inoculants with or without rock mineral fertiliser would be a promising alternative to inorganic fertiliser alone in integrated nutrient management systems of nutrient-poor soils (Pagnani et al., 2018;Tshewang et al., 2020). ...
Industrial hemp (Cannabis sativa L.) production is attracting widespread attention in agriculture but is facing cultivation challenges in nutrient-poor sandy soils. The crop has a fibrous deep taproot system known to have a good association with the rhizosphere soil microbiome. However, there are few reports on incorporating microbial inoculants with or without rock mineral fertilisers to facilitate nutrient mineralisation and stimulate growth of industrial hemp. To test whether microbial consortium inoculant with or without fertiliser improves the growth and yield of industrial hemp by increasing root biomass and nutrient uptake, we assessed the impact of microbial inoculant and rock mineral fertiliser in two hemp varieties (Morpeth and Han FNQ). The experiment was conducted in a randomised complete block design with four treatments: control (CTRL), consortium microbial inoculum (MI), rock mineral fertiliser (MF) and combined microbial inoculum and mineral fertiliser (MI+MF). Plants were grown in compost in a controlled-environment phytotron and harvested 30 and 70 days after sowing (DAS). Han FNQ had higher root dry weight, shoot length, leaf chlorophyll, Mn and Zn uptake than Morpeth at 30 DAS, and Han FNQ in the MI+MF treatment also had greater root volume than Morpeth in all treatments at 30 DAS. At 70 DAS, Morpeth had a higher seed yield than Han FNQ and Morpeth in the MI treatment had greater shoot and root dry weight, leaf chlorophyll, root length and volume, and higher uptake of all macro-and micronutrients in shoots and seeds than Han FNQ in all treatments. These findings suggest that the resource stoichiometry and trade-balance model in plant-microbes symbiosis govern the effectiveness of MI on industrial hemp. The application of MF and the initial nutrients abundance in the compost might suppressed MI activity at 30 DAS whereas, the nutrient limiting condition at 70 DAS might triggered MI activity and symbiotic trade of nutrients between plant and microbes which facilitated root growth and nutrient uptake particularly, in the variety Morpeth.
... In cannabis cultivation, inoculating plants with specific strains of AMF has been shown to improve plant growth and increasing cannabinoids, offering a sustainable alternative to chemical fertilizers (Lyu et al., 2019;Pagnani et al., 2018). For instance, inoculation of hemp KKU05 with the AMF Rhizophagus aggretatus demonstrated improved growth, increased leaf, stem, floret, and root biomass, and elevated concentrations of the cannabinoids CBD and THC compared to the controls, including non-mycorrhizal plants that received supplemental synthetic fertilizer (Seemakram et al., 2022). ...
... For instance, inoculation of hemp KKU05 with the AMF Rhizophagus aggretatus demonstrated improved growth, increased leaf, stem, floret, and root biomass, and elevated concentrations of the cannabinoids CBD and THC compared to the controls, including non-mycorrhizal plants that received supplemental synthetic fertilizer (Seemakram et al., 2022). Similarly, Pagnani et al. (2018) demonstrated that using a mixture of plant growth-promoting rhizobacteria increased plant biomass and cannabinoid content, offering benefits comparable to synthetic N fertilizers. Additionally, AMF help to maintain soil structure, preventing issues like soil hardening and acidity (Fall et al., 2022), which are common with synthetic fertilizers. ...
Industrial hemp (Cannabis sativa L.) is a versatile crop with applications in fiber, seeds, and medicine. Recent legalization has renewed interest in industrial hemp in the United States, particularly in fiber production, which has a critical role in carbon (C) sequestration and various industries, including textiles and construction. A 2‐year field experiment (2022–2023) was conducted at Rodale Institute—Pocono Organic Center, Blakeslee, PA, evaluating the performance of four hemp varieties (MS 77, Futura 75, Santhica 27, and Han NE) under regenerative organic systems. Seed rates were considered as 73 kg ha⁻¹ for Santhica 27 and Futura 75, 135 kg ha⁻¹ for MS 77, and 270 kg ha⁻¹ for Han NE, targeting a plant population of 2.47 million plant ha⁻¹ across varieties. Data on canopy cover, plant height, yields (biomass, stem, leaf, and flower), and cannabinoids were collected to assess the effects of variety and environmental conditions on growth and yield. Root samples from 2023 were also analyzed for arbuscular mycorrhizal fungi (AMF) colonization. Han NE demonstrated the highest growth, yields, and canopy cover, followed by MS 77, with more favorable growing conditions in 2023. Additionally, AMF colonization was consistent across varieties, reporting a higher colonization in MS 77 (45.37%), suggesting enhanced nutrient uptake and stress tolerance. Based on the results, Han NE and MS 77 are promising hemp varieties for fiber production in this region. Further research is required to explore the impact of mycorrhizal colonization on hemp production under varying nutrient conditions for sustainable production.
... In another research, it was found that the presence of suitable conditions for the growth of D. moldavica plants, including increasing the availability of necessary nutrients, especially nitrogen, under the influence of co-application AMF with PGPR under water deficit stress, through improving growth, development, and photosynthesis, leads to an improvement in plant height, and leaves number, which ultimately leads to an increase in the yield of dry weight (Ghanbarzadeh et al., 2019). Inoculated plants also improved stomatal regulation through hormonal adjustment (Pagnani et al., 2018). Production of IAA by symbiotic bacteria may partly explain their effectiveness in promoting plant growth under adverse environmental conditions (Pagnani et al., 2018). ...
... Inoculated plants also improved stomatal regulation through hormonal adjustment (Pagnani et al., 2018). Production of IAA by symbiotic bacteria may partly explain their effectiveness in promoting plant growth under adverse environmental conditions (Pagnani et al., 2018). It has been reported that the inoculation of biofertilizers enhances growth parameters and aerial dry weight in D. kotschyi Boiss. ...
Background
Because of swift climate change, drought is a primary environmental factor that substantially diminishes plant productivity. Furthermore, the increased use of chemical fertilizers has given rise to numerous environmental problems and health risks. Presently, there is a transition towards biofertilizers to enhance crops’ yield, encompassing medicinal and aromatic varieties.
Methods
This study aimed to explore the impacts of plant growth-promoting rhizobacteria (PGPR), both independently and in conjunction with arbuscular mycorrhizal fungi (AMF), on various morphological, physiological, and phytochemical characteristics of Dracocephalum kotschyi Boiss. This experimentation took place under different irrigation conditions. The irrigation schemes encompassed well watering (WW), mild water stress (MWS), and severe water stress (SWS). The study evaluated the effects of various biofertilizers, including AMF, PGPR, and the combined application of both AMF and PGPR (AMF + PGPR), compared to a control group where no biofertilizers were applied.
Results
The findings of the study revealed that under water-stress conditions, the dry yield and relative water content of D. kotschyi Boiss. experienced a decline. However, the application of AMF, PGPR, and AMF + PGPR led to an enhancement in dry yield and relative water content compared to the control group. Among the treatments, the co-application of AMF and PGPR in plants subjected to well watering (WW) exhibited the tallest growth (65 cm), the highest leaf count (187), and the most elevated chlorophyll a (0.59 mg g ⁻¹ fw) and b (0.24 mg g ⁻¹ fw) content. Regarding essential oil production, the maximum content (1.29%) and yield (0.13 g plant ⁻¹ ) were obtained from mild water stress (MWS) treatment. The co-application of AMF and PGPR resulted in the highest essential oil content and yield (1.31% and 0.15 g plant ⁻¹ , respectively). The analysis of D. kotschyi Boiss. essential oil identified twenty-six compounds, with major constituents including geranyl acetate (11.4–18.88%), alpha-pinene (9.33–15.08%), Bis (2-Ethylhexyl) phthalate (8.43-12.8%), neral (6.80–9.32%), geranial (9.23–11.91%), and limonene (5.56–9.12%). Notably, the highest content of geranyl acetate, geranial, limonene, and alpha-pinene was observed in plants subjected to MWS treatment following AMF + PGPR application. Furthermore, the co-application of AMF, PGPR, and severe water stress (SWS) notably increased the total soluble sugar (TSS) and proline content. In conclusion, the results indicate that the combined application of AMF and PGPR can effectively enhance the quantity and quality of essential oil in D. kotschyi Boiss., particularly when the plants are exposed to water deficit stress conditions.
... To our knowledge, there are very limited research data regarding the impact of microbial inoculants on yield and secondary metabolite production of cannabis. A consortium of plant growth-promoting rhizobacteria (PGPR) comprising Gluconacetobacter diazotrophicus, Azospirillum brasilense, Burkholderia ambifaria, and Herbaspirillum seropedicae showed the growth improvement and accumulation of secondary metabolites in hemp (Pagnani et al., 2018). Another study evaluated the effect of a commercial microbial bioinoculant (Mammoth PTM containing beneficial bacteria) on cannabis production in soil-less systems. ...
... Numerous studies have tested the effects of microbial inoculants on the growth and health of cannabis plants, including industrial hemp, recreational cannabis, and medicinal cannabis. However, no study has compared different formulations of inoculants on different cannabis genotypes (Conant et al., 2017;Pagnani et al., 2018). Furthermore, the impact of introduced inoculants on indigenous microbial communities associated with cannabis remains unknown. ...
The root microbiome of medical cannabis plants has been largely unexplored due to past legal restrictions in many countries. Microbes that live on and within the tissue of Cannabis sativa L. similar to other plants, provide advantages such as stimulating plant growth, helping it absorb minerals, providing protection against pathogen attacks, and influencing the production of secondary metabolites. To gain insight into the microbial communities of C. sativa cultivars with different tetrahydrocannabinol (THC) and cannabidiol (CBD) profiles, a greenhouse trial was carried out with and without inoculants added to the growth substrate. Illumina MiSeq metabarcoding was used to analyze the root and rhizosphere microbiomes of the five cultivars. Plant biomass production showed higher levels in three of five cultivars inoculated with the arbuscular mycorrhizal fungus Rhizophagus irregularis and microbial suspension. The blossom dry weight of the cultivar THE was greater when inoculated with R. irregularis and microbial suspension than with no inoculation. Increasing plant biomass and blossom dry weight are two important parameters for producing cannabis for medical applications. In mature Cannabis, 12 phytocannabinoid compounds varied among cultivars and were affected by inoculants. Significant differences (p ≤ 0.01) in concentrations of cannabidivarinic acid (CBDVA), cannabidivarin (CBDV), cannabigerol (CBG), cannabidiol (CBD), and cannabigerolic acid (CBGA) were observed in all Cannabis cultivars when amended with F, K1, and K2 inoculants. We found microbes that were shared among cultivars. For example, Terrimicrobium sp., Actinoplanes sp., and Trichoderma reesei were shared by the cultivars ECC-EUS-THE, CCL-ECC, and EUS-THE, respectively. Actinoplanes sp. is a known species that produces phosphatase enzymes, while Trichoderma reesei is a fungal train that produces cellulase and contributes to organic matter mineralization. However, the role of Terrimicrobium sp. as an anaerobic bacterium remains unknown. This study demonstrated that the use of inoculants had an impact on the production of phytocannabinoids in five Cannabis cultivars. These inoculants could have useful applications for optimizing cannabis cultivation practices and increasing the production of phytocannabinoids.
... Sativa) from the catalogue of cultivars not only in Slovenia but also in other European countries. Pagnani et al. (2018) and Tang et al. (2022) found large differences in cannabinoid content between cultivars grown under uniform conditions (ANOVA p < 0.05) and within a single cultivar. Sausserde et al. (2013) investigated the level of nitrogen nutrition in the cultivar 'Futura'. ...
... However, the best option to evaluate lignocellulose quality is to provide the valuation in terms of quality content and quality yield as well, while an important impact on nutrition can be expected (Kron et al. 2017;Tóth & Dupľák 2023). Pagnani et al. (2018) also recorded the positive effect of plant growth-promoting rhizobacteria (PGPR) on the aboveground biomass of hemp, as well as the accumulation of plant secondary metabolites and consequently antioxidant capacity. Even the lowest concentration of PGPR made the same effect as recommended nitrogen fertilisation in a dose of 60 kg N/ha. ...
Hemp (Cannabis sativa L.) is one of the traditional crops currently being newly re-introduced in Slovakia and cultivated for multi-purpose uses, while still there is a lack of crop biomass yield data. The main objective of the paper is to document the yield of aboveground biomass of selected cultivars of hemp ('Bialobrzeskie', 'Felina', 'Santhica', 'Epsilon', and 'Futura'), which were tested in the pilot open-field experiments conducted during 2009 − 2012, immediately after a wave of legislative changes. The trial was agronomically designed including three nitrogen treatments as follows: (i) T1 30 kg N/ha (the full 30 kg/ha in the phenophase BBCH 31), (ii) T2 60 kg N/ha (dividing on 30 + 30 kg/ha in the phenophase BBCH 31 and 51, respectively), and (iii) T3 90 kg N/ha (dividing on 30 + 30 + 30 kg/ha in the phenophase BBCH 31, 51 and 59, respectively); whereas NPK 15-15-15 in the dose of 200 kg/ha was applied before the sowing all across the treatments. The total average dry matter (DM) yield of 9.49 t/ha was achieved, ranging from 2.12 to 16.80 t/ha. DM yield was affected mainly by years (F-ratio 337.40, P-value 0.0000), followed by nitrogen treatment (F-ratio 47.86, P-value 0.0001), then by cultivars (F-ratio 22.37, P-value 0.0019) and finally by replications (F-ratio 0.65, P-value 0.58). However, the need for further studies aimed to quantify more precisely the response of the cultivars to the weather and soil conditions is necessary, especially the cultivars of new and foreign origin.
... The control group, maintained under standard conditions, achieved an average weight of 92.82 g. This notable variation highlights the importance of selecting an appropriate growing medium composition to maximize cannabis yield [18]. The superior performance of the F2 indicates that a wellbalanced mixture of organic and inorganic components may provide the essential nutrients and support required for optimal cannabis cultivation. ...
The rising global demand for medicinal cannabis necessitates the optimization of cultivation, harvesting, and extraction techniques to maximize cannabinoid yield and purity. This study investigates the Foi Thong Phu Pha Yon strain under controlled environmental conditions, evaluating the effects of temperature, humidity, CO2 concentration, and light exposure on plant growth and cannabinoid biosynthesis. A total of 170 seeds were germinated, with an 85% germination success rate, and various growth strategies, including soil composition, nutrient application, and irrigation methods, were tested to determine the most effective approach. The research findings indicate that vegetative growth was optimal at 27 ◦C, 70% humidity, and 1200 ppm CO2 while flowering required a reduced temperature (22 ◦C), lower humidity (50%), and elevated CO2 levels (1900 ppm) to enhance cannabinoid production and prevent disease. Furthermore, harvest timing significantly influenced CBD yield, with peak cannabinoid content observed when 80% of trichomes were cloudy white. Over two growing cycles, this study produced 43,200 g of fresh buds, resulting in 7560 g of dried cannabis buds. The extraction process, utilizing dynamic maceration with 95% ethanol, followed by winterization and chromatography, yielded 2343.60 g of cannabis extract, including 589.68 g of CBD, with an average purity of 86.599%. Advanced techniques such as flash chromatography and distillation further refined the CBD isolate, ensuring pharmaceutical-grade quality. These findings highlight the effectiveness of precise environmental control, strategic harvesting, and advanced extraction methodologies in optimizing cannabis production. This research provides valuable insights for agricultural researchers, policymakers, and the pharmaceutical industry, supporting sustainable cultivation practices and improved product quality in the expanding medicinal cannabis market.
... The complicated relationship between plants and microbes in the context of medicinal plants is of special significance given the critical importance of the production of bioactive compounds in these crops. Microbes can promote the growth of medicinal plants and their resistance through a variety of mechanisms, the most important of which is to promote the synthesis of therapeutic compounds, including the production of plant hormones, thereby enhancing dissolved nutrients and regulating plant gene expression [5,6]. The endophytic association between Dictyophora indusiata and Bacillus aryabhattai stimulated production of growth-promoting metabolites (lysoPC 18:1 and dihydrobenzofuran) in sugarcane roots, enhancing both crop yield and flavonoid metabolism during endophytic phenotype development [7]. ...
Intercropping is a promising strategy for sustainable medicinal plant cultivation, but its impact on plant–microbe interactions remains poorly understood. This study investigated the influence that intercropping giant lily (Cardiocrinum giganteum) with bamboo (BG), Chinese fir (FG), and mixed forests (MG) had on the giant lily metabolome and microbiome compared to a monoculture control (GG). Metabolomic analysis revealed that BG significantly increased the accumulation of terpenoids (e.g., yucalexin B22, 19.39-fold), alkaloids (e.g., anabasine, 2.97-fold), and steroids (e.g., O-acetyl-lariciresinol, 4.49-fold), while MG induced the production of stress-related metabolites (e.g., aflatoxin G2, 128.62-fold), and FG enhanced nitrogen metabolism (e.g., putrescine, 2.47-fold). Intercropping altered the rhizosphere and endophytic microbial communities, with BG enriching beneficial bacteria (e.g., Acidobacteria and Alphaproteobacteria) and FG promoting symbiotic fungi (e.g., Serendipita and Xylariales). Network analysis revealed strong correlations between specific microbial taxa (e.g., Bacillus and Ceratobasidiaceae) and key metabolites (e.g., norpandamarilactonine A, methylgingerol), indicating their potential roles in shaping the metabolic profiles of giant lily. These findings highlight the complex interplay between intercropping systems, microbial communities, and medicinal plant metabolism and provide a basis for developing targeted cultivation strategies to enhance the production of bioactive compounds in giant lily and other medicinal plants.
... Other authors' studies describe 'Finola' as a short variety of seed hemp [30,31]. 'Purini', in a study by other authors, shows a similar plant height under equivalent climatic conditions [32]. ...
As the world shifts towards more sustainable and eco-friendly practices, industrial hemp (Cannabis sativa L.) is gaining recognition as a versatile crop with numerous applications. The Baltic Sea region is well-suited for hemp cultivation, with its temperate climate and varied soil types. This study evaluates the suitability of various hemp varieties for the region, focusing on their ability to produce high-quality biomass, fibers, seeds, and dual-purpose products. The findings will contribute to the development of a thriving hemp industry in the region. Five years of research was conducted to investigate the productivity of 12 industrial hemp varieties, including 7 varieties mainly developed for seed production and 5 varieties mainly designed for fiber production. The results showed significant differences in yields among the varieties, with ‘Bialobrzeskie’ exhibiting the highest biomass yield (47.2 t ha⁻¹) and ‘Futura 75’ producing the highest fiber yield (10.8 t ha⁻¹). ‘Henola’ demonstrated the highest seed yield (3.5 t ha⁻¹), while ‘KA-2-2011’ and ‘USO-31’ were identified as dual-purpose varieties suitable for fiber (3.4 and 6.4 t ha⁻¹, respectively) and seed production (2.2 and 1.3 t ha⁻¹, respectively). The calorific value of hemp shives is comparable to wood fuels, indicating their potential as a viable fuel source. The results offer farmers a crucial tool for selecting the best-suited varieties for their specific region, promoting sustainable agriculture practices.
... en diferentes tipos de muestras del cultivo evaluado sugiere una alternativa prometedora a los fertilizantes químicos en este sistema productivo. Estas bacterias pueden promover el crecimiento y desarrollo de las plantas a través de varios mecanismos, tales como: fijación de nitrógeno atmosférico, producción de sideróforos (los sideróforos quelatan el hierro para estar disponible para la raíz de la planta), solubilización de minerales (particularmente fósforo), producción de sustancias promotoras del crecimiento de las plantas (como auxinas, citoquininas, giberelinas) y la síntesis de varios otros compuestos promotores del crecimiento (por ejemplo, enzimas), así mismo estimulan el alargamiento de los sistemas radiculares, formación de raíces laterales y adventicias, pelos radiculares y pelos radiculares ramificados, juega un papel importante en la mejora de crecimiento y rendimiento de cultivos en diversas condiciones ambientales y del suelo (Pagnani et al., 2018). ...
The crop of medicinal cannabis has developed great importance in recent years in Colombia and other Latin American countries. Considering the production characteristics of the crop, which is fundamentally based on organic models, it is important to know the microorganisms that accompany the production system and their possible implications for management. In this research were isolated and characterized the microorganisms in the different phases of production of a high-density cannabis crop: planting, or propagation areas, production areas, and postharvest areas (flower pre-drying). In each area samples of soil, substrates and water were taken and the microorganisms present were identified by direct sowing in culture media, using microscopic identification and molecular characterization. A high diversity was found in all production areas, and it was evidenced that beneficial microorganisms (Trichoderma spp. and Bacillus spp.) applied to the production system regulate the populations of microorganisms in the soil and in the substrates. It was identified that perlite and coconut fiber allow the development of populations of phosphorus solubilizing and nitrogen fixing microorganisms and that the production of compost using crop waste is safe at a sanitary level. No populations of pathogens were identified in any of the samples evaluated at levels that could explain the presence of diseases in the crop.
... Sunflower is an excellent plant for studying biostimulating capability because of its high biomass production, expansive root system, and economic significance [61]. The seeds were surface sterilized with a sodium hypochlorite solution and rinsed several times with sterile distilled water [62,63]. Inoculation was performed by immersing the sunflower seeds in the consortium (10 6 CFU/mL) for 1 hour. ...
Sustainable alternatives are essential to improving agriculture production to meet the growing world's critical demands. Cyanobacteria and microalgae are considered renewable resources with a wide range of potential uses in the agricultural sector. We aimed to isolate cyanobacteria and microalgae from the mud of a carbon dioxide-rich sulfur pond and to investigate their plant growth-promoting (PGP) and soil bio-consolidating ability. Mud samples were subjected to DNA extraction and 16S rRNA gene sequencing to characterize the prokaryotic community. Phototrophic culturable microbiota was isolated and evaluated for different PGP properties. The most relevant isolates were combined in a consortium and used for in vitro bioconsolidation activity. In a greenhouse experiment, the isolates were evaluated for their ability to promote salinity stress tolerance in sunflower plants. Metabarcoding results showed that most Amplicon Sequence Variants (ASV) were associated with Actinobacteriota (35%), Proteobacteria (19%), and Acidobacteriota (11%) at the phylum level and Unknown (32%) and uncultured (31%) lineages at the genus level. The culture-dependent method yielded eight isolates associated with cyanobacteria and microalgae genera. The isolates obtained showed interesting PGP activities. Isolates C1, C2, and M1 were selected based on phosphate solubilization (85.6 µg PO4³⁻ mL⁻¹ on average), indoles (C1 and M1 0.54 µg mL⁻¹ IAA equivalents on average), and ACC deaminase activity (C2 and M1 6.00 µmol α-KB mg proteins⁻¹ h⁻¹⁾. The consortium efficiently consolidated sand particles in the presence of calcium carbonate by forming biomineralized aggregates. In planta results showed positive effects of the consortium on Helianthus annuus L., plant growth under normal conditions and salt stress. The positive effects on soil and plants indicated their effectiveness as bioconsolidants and biostimulant agents. Our findings highlight the interesting potential of cyanobacteria and microalgae applications in sustainable agriculture.
... Combining two or more strains with plant growth-promoting (PGP) traits to enhance the inoculum's efficacy is a proven method (Deter and Lu, 2022). The bacterial consortium consisting of Herbaspirillum seropedicae Z67, Gluconacetobacter diazotrophicus Pal5, Azospirillum brasilense Cd, and Burkholderia ambifaria PHP7 has been shown to have positive biostimulating effects on various crops, including tomato, carrots, hemp, Apennines genepì, and ancient Triticum genotypes (Del Gallo et al., 2010;Botta et al., 2013;Pagnani et al., 2018;Pagnani et al., 2020;Pellegrini et al., 2020a;Pellegrini et al., 2021a;Pellegrini et al., 2021b). ...
Microbial-based inoculants for agricultural use consist of different strains. The consortia production process involves growing pure cultures separately and combining them in the appropriate ratio. However, the inclusion of multiple strains in the formulation increases production costs. By developing co-culture fermentations, it is possible to create consortia with the correct bacterial charge. This study aims to develop a cost-effective co-culture approach for producing an inoculum that includes the appropriate ratio of four Gram-negative bacteria, i.e., Azospirillum brasilense, Burkholderia ambifaria, Gluconacetobacter diazotrophicus, and Herbaspirillum seropedicae. The specific growth rates of strains were studied using the T4 medium, previously optimized for their culture. The co-fermentation process was optimized in 500 mL flasks to attain an equivalent density of 9.7-10 Log CFU mL-1. Then, it was successfully scaled up to a 5 L bioreactor, obtaining an equivalent density of 9.7-9.9 CFU mL-1. This first co-formulation of a four multistrain consortium formed by Gram-negative plant growth-promoting bacteria pave the road for future evaluations of other products useful for sustainable agriculture.
... The increase in anthocyanins in this study, despite repeated use of wastewater and graywater, could be attributed to the presence of bacterial strains. The results of this study, which showed an increase in anthocyanins through substrate inoculated with Mix B3 in irrigated vegetable plants with recycled water, are consistent with the reports of Pagnani et al., [80] and Kumar et al., [62]. ...
Background
Rapid urbanization and population growth exert a substantial impact on the accessibility of drinking water resources, underscoring the imperative for wastewater treatment and the reuse of non-potable water in agriculture. In this context, green walls emerge as a potential solution to augment the purification of unconventional waters, simultaneously contributing to the aesthetic appeal and enjoyment of urban areas. This study aims to optimize water management in green walls by investigating the impact of bacterial strains on the biochemical properties and performance of the ornamental accumulator plant, Aptenia cordifolia, grown with various unconventional water sources. The experiments were designed as split plots based on a completely randomized block design with three replications. The main factor was recycled water with three levels (gray water, wastewater from the Kashfroud region of Mashhad, and urban water (control)). The sub-factor included different bacterial strains at four levels, composed of various bacteria combinations, (B1: Psedoumonas flucrecens + Azosporillum liposferum + Thiobacillus thioparus + Aztobactor chorococcum, B2: Paenibacillus polymyxa + Pseudomonas fildensis + Bacillus subtilis + Achromobacter xylosoxidans + Bacillus licheniform, B3: Pseudomonas putida + Acidithiobacillus ferrooxidans + Bacillus velezensis + Bacillus subtilis + Bacillus methylotrophicus + Mcrobacterium testaceum, and the control level without bacterial application (B0).
Result
The findings revealed significant differences at the 5% probability level across all morphophysiological traits, including plant height, the number and length of lateral branches, growth index, and plant coverage. Moreover, superior morphophysiological traits were observed in plants cultivated in substrates inoculated with wastewater irrigation. Substrates inoculated with bacteria exhibited the highest relative water content (RWC) and chlorophyll levels, coupled with the lowest relative saturation deficit (RSD), electrolyte leakage (EL), and carotenoid levels. Furthermore, plant growth-promoting bacteria (PGPB), from a biochemical perspective, were associated with increased carbohydrates, total protein, and anthocyanin. They also contributed to controlling oxidative stress caused by free radicals by enhancing the activity of antioxidant enzymes, such as guaiacol peroxidase (GPX), polyphenol oxidase (PPO), ascorbate peroxidase (APX), and peroxidase (POD), while reducing catalase enzyme (CAT) activity. This led to increased resistance to stress, as evidenced by a decrease in malondialdehyde and proline levels. The study concludes that the MIX B3, being both ecofriendly and economical, represents an effective strategy for mitigating the adverse effects of wastewater on plants.
Conclusion
This study showed that plant irrigation using wastewater increases the levels of proline, phenols and oxidative stress. However, the application of plant growth promoting bacteria (PGPB) reduced oxidative damage by increasing antioxidant activity and decreasing proline and phenol levels. These findings show the potential of bacterial treatments to improve plant growth and reduce adverse effects of recycled water irrigation.
... (Toth et al., 2020) Aplicação de Rhizobacteria promotoras de crescimento de plantas em variedades de cânhamo, bem como investigar seus efeitos em outros parâmetros agronômicos e ambientais, como a biodiversidade do solo e a redução de insumos químicos. (Pagnani et al., 2018) Cluster 4 ...
Fungal contamination is an important problem in cannabis and medical cannabis production, as fungi can produce toxic compounds or reduce the quality and safety of the product. The aim of this study was to perform a bibliometric evaluation related to fungal contamination in cannabis, analyzing current trends in this field and providing future perspectives for research. For this purpose, an exhaustive search was carried out in the scientific literature in electronic databases such as Scopus and Web of Science (WOS), covering the period from 2000 to 2023. The results obtained were processed through bibliometrics and network analysis, using tools such as RStudio and Bibliometrix software. The results revealed that the main themes associated with fungal contamination in cannabis are focused on: diseases related to fungal contamination of the plant, use of fungi as an alternative biological control in cannabis cultivation, metabolites associated with cannabis and their potential in fungal control, as well as fungal diversity in cannabis cultivation and postharvest and the risk to consumer health. Finally, future research areas are proposed to address the challenge of fungal contamination in medicinal cannabis production, covering topics such as pest control, contamination, genetic resistance, active compounds, analysis methods, and the impact of fungi on cannabis.
... Microbiome engineering, with the aim of exploiting plant-associated microbes to enhance yield, quality, and resilience, represents a sustainable, complementary strategy to traditional breeding approaches. Plantgrowth-promoting rhizobacteria have been found to enhance hemp growth (Islam et al., 2023;Lyu et al., 2022;Pagnani et al., 2018). The hemp microbiome also has unique roles in mediating the retting process (Liu et al., 2017;Ribeiro et al., 2015;Zhang et al., 2008), crucial for natural fibre production and which determines fibre quality and processing efficiency (Law et al., 2020). ...
The seed‐endophytic bacterial community is a potentially beneficial and heritable fraction of the plant microbiome. Its utilization as a sustainable crop improvement strategy could be especially valuable for species such as hemp, where production is being scaled up and new challenges will be faced in managing crop productivity and health. However, little is known about the makeup and variation of the hemp seed microbiome. This study profiled the endophytic bacterial communities harboured by 16 hemp cultivars sourced from commercial suppliers in Europe. A 16S rDNA amplicon sequencing approach identified 917 amplicon sequence variants across samples. Taxonomic classification of sequences revealed 4 phyla and 87 genera to be represented in the dataset. Several genera were widespread while some were specific to one or a few cultivars. Flavobacterium, Pseudomonas, and Pantoea were notable in their high overall abundance and prevalence, but community composition was variable and no one taxon was universally abundant, suggesting a high degree of flexibility in community assembly. Taxonomic composition and alpha diversity differed among cultivars, though further work is required to understand the relative influence of hemp genetic factors on community structure. The taxonomic profiles presented here can be used to inform further work investigating the functional characteristics and potential plant‐growth‐promoting traits of seed‐borne bacteria in hemp.
... Several studies unveiled that using PGPR is an efficient way to counteract the negative impacts of numerous environmental stresses (Bacilio et al., 2004;de-Bashan et al., 2012;Djebaili et al., 2021;Etesami and Beattie, 2017;Etesami and Maheshwari, 2018;Grover et al., 2011;Kim et al., 2012;Qin et al., 2016). It is supposed that the release of several chemicals (such as elicitors and antibiotics) and the induction of the ISR are responsible for this ability (Compant et al., 2005;Etesami and Maheshwari, 2018;Glick, 2004Glick, , 2010Glick, , 2014Pagnani et al., 2018Pagnani et al., , 2020. Plants can respond to stresses by activating defense mechanisms that are either systemically distributed throughout the plant or restricted to the injured organ (Romera et al., 2019). ...
... They pose a risk of environmental pollution, they may lead to fungal resistance and they reduce the populations of beneficial soil microbes (Cardoso et al., 2010;Chandini et al., 2019). Therefore, using microorganisms such as endophytic fungi as biological control agents is an attractive alternative to standard synthetic fungicides (Zucchi et al., 2008;Pagnani et al., 2018;Suebrasri et al., 2020). Endophytic fungi are one of the environmentally-friendly approaches for enhancing plant growth and biocontrol. ...
... In order to overcome this problem, there is an urgent need for innovative biotechnological approaches to explore the beneficial associations between plants and certain microorganisms as sustainable and environmentally friendly biofertilizers. These growthpromoting organisms, including bacteria, fungi and cyanobacteria with the ability to enhance plant growth and elicit the efficient production of plant-based valuable biomolecules, present a promising alternative to synthetic biofertilizers (5)(6). Cyanobacteria are a highly diverse group of Gramnegative photosynthetic prokaryotes found in different types of aquatic and terrestrial environments. ...
Background: Mentha piperita L. is one of the most important aromatic crops and is cultivated worldwide for essential oils (EOs).
Objectives: The aim of the present study was to investigate the potential of two cyanobacteria, Anabaena vaginicola ISB42
and Nostoc spongiaeforme var. tenue ISB65, as biological-elicitors to improve the growth and essential oil production of
M. piperita.
Materials and Methods: In this experiment, inoculation of M. piperita with cyanobacteria was performed by adding
1% cyanobacterial suspension to the soil of treated pots on the first time of planting and every 20 days thereafter. The
experiment was performed in a randomized complete block design in an experimental greenhouse condition. After 90 days
planting, the vegetative growth factors, the content of photosynthetic pigments, as well as the quantity and quality of EOs
of treated and control plants were evaluated. Also, quantitative changes in the expression of some menthol biosynthesis-
related genes were investigated.
Results: Cyanobacterial application led to significant increases in M. piperita growth indices including root and shoot
biomass, leaf number, leaf area, node number and ramification, as well as photosynthetic pigments content. The statistical
analysis showed a 41-75 % increase in some of these growth indices, especially in Nostoc-treated plants. A. vaginicola and
N. spongiaeforme var. tenue inoculation led to a 13% and 25% increase in the EOs content of M. piperita, respectively.
The EOs components were also affected by cyanobacterial treatments. According to the statistical analysis, Nostoc-treated
plants showed the highest amount of (-)-menthone and (-)-limonene, with a 2.36 and 1.87-fold increase compared to the
control. A. vaginicola and N. spongiaeforme var. tenue inoculation also led to 40% and 98% increase in transcript level of
(-)-limonene synthase gene, respectively. The expression of the (-)-menthone reductase gene, was also increased by 65%
and 55% in response to A. vaginicola and N. spongiaeforme var. tenue application, respectively.
Conclusions: Our data demonstrated that in addition to growth enhancement, these two heterocystous cyanobacteria
improved the quantity and quality of EOs by up-regulating the key genes involved in the menthol biosynthetic pathway.
Based on our results, these cyanobacteria can be considered valuable candidates in the formulation of low-cost and
environmentally friendly biofertilizers in sustainable peppermint production.
... Unscientific use of chemical fertilizer in crop production not only caused low yield and waste of fertilizer but also lead to increased production costs apart from contaminating the soil and water. In order to promote environment-friendly and sustainable agricultural systems, the concept of ecofriendly agriculture through application of PGPR consortia is a new field of interest without compromising the yield and quality of crop (Pagnania et al., 2018). Hence, study was framed with the intention to assess the influence of spacing and nutrients plus PGPR consortia on economics of cultivation of hemp for both fiber and seed purposes. ...
Hemp is dual purpose crop, where fibers and seeds have found its place in textile and food industry due to its strong fiber and nutrition content in seed. The cultivation of hemp is a new venture in India where farmers get dual income by both fibers and seeds hence, optimizing spacing and nutrient management to harness maximum yield of fiber and seed can double the income of farmers. The present investigation on economics of hemp cultivation revealed that the, maximum gross returns (Rs. 5,74,000/ ha) were obtained from plants grown at 10 cm × 5 cm spacing and supplied with 125 per cent RDF plus PGPR consortia but highest B:C ratio of 4.68 was observed in plants grown at spacing of 20 cm × 10 cm and nourished with 100 per cent of RDF plus PGPR consortia for fiber purposes. Upon considering seed economics maximum gross returns (Rs. 12,58,200/ ha) was recorded in the treatment combination of 10 cm × 10 cm spacing and supplied with 125 per cent RDF plus PGPR consortia while, maximum B:C ratio of 13.17 was noted from plots where plants were spaced at 15 cm × 10 cm and supplied with nutrition of 100 per cent RDF plus PGPR consortia for seed purposes.
... Such systems offer more control of the overall production, with a higher degree of specialization, modification of the environmental conditions (i.e., light, air circulation, humidity and temperature) and plant abiotic stress induction (Cervantes, 2006;Jin et al., 2019;Malıḱ et al., 2021). However, indoor systems are energy-and resource-intensive (Madhusoodanan, 2019;Wartenberg et al., 2021) while negatively affecting the environment through water, air and land pollution due to high water and fertilizer consumption (Pagnani et al., 2018;Zheng et al., 2021). ...
Indoor medicinal cannabis cultivation systems enable year-round cultivation and better control of growing factors, however, such systems are energy and resource intensive. Nutrient deprivation during flowering can trigger nutrient translocation and modulate the production of cannabinoids, which might increase agronomic nutrient use efficiency, and thus, a more sustainable use of fertilizers. This experiment compares two fertilizer types (mineral and organic) applied in three dilutions (80, 160 and 240 mg N L⁻¹) to evaluate the effect of nutrient deprivation during flowering on biomass, Cannabidiol (CBD) yield and nutrient use efficiency of N, P and K. This is the first study showing the potential to reduce fertilizer input while maintaining CBD yield of medicinal cannabis. Under nutrient stress, inflorescence yield was significantly lower at the final harvest, however, this was compensated by a higher CBD concentration, resulting in 95% of CBD yield using one-third less fertilizer. The higher nutrient use efficiency of N, P, and K in nutrient-deprived plants was achieved by a larger mobilization and translocation of nutrients increasing the utilization efficiency of acquired nutrients. The agronomic nutrient use efficiency of CBD yield – for N and K – increased 34% for the organic fertilizers and 72% for the mineral fertilizers comparing the dilution with one-third less nutrients (160) with the highest nutrient concentration (240). Differences in CBD yield between fertilizer types occurred only at the final harvest indicating limitations in nutrient uptake due to nutrient forms in the organic fertilizer. Our results showed a lower acquisition and utilization efficiency for the organic fertilizer, proposing the necessity to improve either the timing of bio-availability of organic fertilizers or the use of soil amendments.
... Beyond genetics, the content of cannabinoids is affected by sex (Nagy et al. 2019), ontogeny (Ingallina et al. 2020) and variety of environmental factors (Campbell et al. 2019). Among them light intensity and spectrum (Danziger and Bernstein 2021a;Magagnini, Grassi, and Kotiranta 2018), temperature (Galic et al. 2022), drought (Caplan, Dixon, and Zheng 2019;Sheldon et al. 2021), nutrients (Bernstein et al. 2019;Saloner and Bernstein 2021, 2022a, 2022bShiponi and Bernstein 2021), heavy metal (Husain et al. 2019) and plant growth-promoting rhizobacteria (Pagnani et al. 2018) have been reported. Exposure to heavy metals significantly increased total CBD and THC content in hemp plants (Husain et al. 2019). ...
Cannabis sativa L. is an extremely variable species. Even within the same cultivar plants can significantly differ in the content and profile of cannabinoids. Therefore, the best method for production of uniform plants and standardized raw material is vegetative propagation using clones. The aim of this study was to determine the content of cannabidiolic acid (CBDA), cannabidiol (CBD), Δ⁹-tetrahydrocannabinolic acid (Δ⁹-THCA), Δ⁹-tetrahydrocannabinol (Δ⁹-THC), cannabichromene (CBC), cannabigerol (CBG), and cannabinol (CBN) in clonally propagated plants of industrial hemp. One hundred and thirty-nine plants representing 17 different hemp genotypes were regenerated in vitro, hardened, and grown in a vegetation hall until harvest. Single plants of each accession were analyzed using high-performance liquid chromatography with UV/diode-array detection (HPLC-DAD/UV). The results revealed significant variability in the total cannabinoid content (0.55–5.18% in dry weight) among tested genotypes and within the Epsilon 68 cultivar. The highest content of total CBD (4.410%) was recorded for EPS/40 genotype, while the level of total Δ⁹-THC was below the allowed threshold (0.3%). Therefore, we can conclude that some clonally propagated plants provided reproducible hemp material as a potential source of cannabidiol. The results of this study will be useful for breeding and early selection of hemp genotypes.
... The systemic microbial endophytic colonization from roots upwards to buds has been reported in cannabis under field conditions (Taghinasab and Jabaji, 2020). Bacterial endophytes have been reported to improve plant growth and development as well as the accumulation of plant secondary metabolites in industrial hemp (Finola) (Pagnani et al., 2018). Arbuscular mycorrhiza fungi can enhance the tolerance of industrial hemp to heavy metal accumulation (Citterio et al., 2005). ...
... In this study, leaf chlorophyll increased with elevated P rate, with 22% higher values at P 80 than P 0 , and 18% and 13% higher in Morpeth than Han FNQ and Fedora 17, respectively (Table 4). SPAD readings positively correlate with leaf N concentration and reflect leaf chlorophyll concentration (Burgel et al. 2020;Pagnani et al. 2018). Studies have reported reduced chlorophyll concentrations in medical cannabis under P starvation, attributed to reduced leaf N as an indirect effect of P on chlorophyll production (Shiponi and Bernstein 2021a, b). ...
Background and Aims
Phosphorus (P) is a restricting nutrient for crop productivity worldwide. P deficiency can lead to stunted growth and development, eventually affecting crop yield. But less is documented about the impact of P fertility on industrial hemp (Cannabis sativa L.) production in the low-P soils of south-western Australia. We aimed to investigate the effect of P rates on growth, physiology, rhizosphere carboxylate exudation, nutrient uptake and P-use efficiency in hemp.
Methods
The study was conducted in a randomised complete block design with four P rates (0, 40, 80 and 120 mg P kg–1 dry soil) and three hemp varieties (Morpeth, Han FNQ and Fedora 17). Plants were grown and raised in a controlled-environment phytotron until harvested 35 days after sowing at vegetative growth stage (3rd to nth leaf pair).
Results
Our results revealed a strong influence of treatment (P rate) on hemp growth, physiology, biomass, nutrient uptake and P-use efficiency compared to variety and the variety × treatment interaction. Hemp roots predominantly released citrate in P-deficient conditions and gradually shifted to malate exudation with increasing P supply. The N:P ratio, leaf chlorophyll, and gas exchange data coupled with shoot and root length data suggest that Morpeth and Fedora 17 differ in morpho-physiological adaptations for optimum photosynthesis and growth, with high leaf chlorophyll and coarse root length achieved by Morpeth and high intercellular CO2 concentration and shoot length by Fedora 17.
Conclusions
Morpeth and Fedora 17 had high shoot biomass, root length, root surface area and agronomic P-use and P-utilisation efficiencies in response to increasing soil P, while Han FNQ had moderate shoot yield, root growth, high citrate exudation, tissue P concentration and P-uptake efficiency.
... The results of our experiments showed that inoculation of rapeseed with AMF and PGPB under salinity stress improved gas exchange and photosynthetic pigment content. The results presented for Piper nigrum L. (Moreira et al. 2020) and Cucurbita pepo L. (Amiri et al. 2017;Pagnani et al. 2018) are consistent with those obtained in the present study. In those investigations, symbiosis with AMF improved water absorption and retention by increasing mycelial density and stomatal conductance to maintain photosynthetic capacity under salinity stress. ...
Salinity stress is a major threat that negatively affects plant growth and production in arid and semi-arid regions. Application of biofertilizers could mitigate this stress. Accordingly, a pot experiment was conducted on rapeseed grown under salinity stress (0, 5, 10, and 15 dS m −1) while considering the following additives: (1) AMF (non-inoculated and inoculated with Glomus versiforme) and (2) PGPR (non-inoculated and inoculated with Micrococcus yunnanensis). The present results showed that salinity stress led to significant reductions in growth, yield, yield components, and physiological attributes, while raising the Na + /K + ratio. However, with the application of PGPR and AMF, the increased salinity tolerance of rapeseed resulted in a significant improvement in redox status and ion homeostasis. They considerably improved antioxidant enzymatic activity and plant nutrition status. Furthermore, the co-inoculation of PGPR and AMF increased chlorophyll a, chlorophyll b, carotenoids, photosynthesis rate, and percentage of rapeseed oil under 15 dS m −1 1.7-, 1.8-, 2.3-, 2.0-and 1.3-times, respectively, compared with the non-inoculation treatment. These findings indicate that the integral application of PGPR and AMF is essential for alleviating salinity stress.
... Microbial biofertilizers represent an alternative strategy to promote plant growth, but their output is still controversial. In some reports, the application of microbial consortia resulted in similar yields as conventional mineral fertilizers (Adesemoye et al., 2009;Pagnani et al., 2018), whereas other studies showed the necessity of NPK application along with microbial strains to improve plant growth and yield (Esitken et al., 2010;ilagar et al., 2016). Nevertheless, the addition of a chemical fertilizer to microbial consortia does not seem to ameliorate the soil properties aer harvest (angasamy & Lawande, 2015), neither chemical (organic carbon, available nitrogen, phosphorus, and potassium) nor microbial (bacterial, Actinomycetes, and Acta Agrobotanica / 2023 / Volume 76 / Article 168485 Publisher: Polish Botanical Society fungal count) (Tinna et al., 2020). ...
The need for an agricultural system in the Mediterranean countries consuming fewer chemicals and respecting the environment becomes a pressing element. The use of natural beneficial microorganisms that enhance soil fertility could be a promising solution. Lebanese Beneficial Microorganisms (LBM) were extracted and evaluated for their capacity of promoting plant growth. Two combinations of LBM were compared to chemical fertilizers: alone (treatment B) or with an organic fertilizer (treatment A). Under field conditions, significant positive effects on height, leaf biomass, and fruit production were obtained starting from day 15 for both tested crops. Treatment A was the most efficient in enhancement of different growth parameters. Hence, Capsicum annuum shoots were 44.4% longer with 99.5% and 51.2% increase in the number of leaves and flowers per plant, respectively. Fruit yield increased over the control by 31.7% in C. annuum and 37.5% in Solanum lycopersicum . However, treatment B exhibited the highest significant values of root length and weight in S. lycopersicum . This study highlights the efficiency of both LBM combinations in the total absence of chemical fertilizers and the increase in their outcome by the addition of organic products. The use of native microbial consortia represents a novel strategy for the development of biofertilizers.
... Lyu et al. (2022a) demonstrated an improvement of inflorescence fresh weight with three separate rhizobacterial species, of which two increased the number of inflorescences per plant. Using hemp cultivars, Pagnani et al. (2018) revealed that PGPR inocula also affected the metabolite profiles of their cultivars. With regards to pathogen control, Balthazar et al. (2022a) have recently shown the efficacy of twelve strains of Bacillus and Pseudomonas against culturable cannabis fungal pathogens and found 5 strains had a significant biocontrol impact on reducing gray mold development in planta. ...
Cannabis sativa remains under heavy legal restriction around the globe that prevents extensive investigations into agricultural applications for improving its development. This work investigates the potential of specific plant growth-promoting rhizobacteria (PGPR) to improve Cannabis cannabinoid yield through increased trichome densities on floral organs, and to determine if sub-optimal environmental conditions would affect the outcomes of PGPR presence by altering plant development and cannabinoid profiles. Here, Pseudomonas sp. or Bacillus sp. were applied to the root system either separately or in a consortium to determine the effect of this bacterial treatment on the density of stalked glandular trichomes. Further, a low nutrient regime was applied for the first half of plant development to determine if an environmental stressor interacts with the effects of the microbial treatments on stalked trichome densities. Following 8 weeks of flower development, trichome density on calyces and bracts of inflorescences were determined using microscopy. Our findings unexpectedly indicate that recommended nutrient levels were linked to a decreasing trend in trichome densities with PGPR inoculations, but a low nutrient regime coupled with PGPR treatment increased them. Cannabinoid content is partially consistent with these results, in that a low nutrient regime increased the abundance of key cannabinoids compared to recommended regimes, with Bacillus sp. inoculation linked to the greatest number of significant changes between the two nutrient regimes. Overall, this work provides insight into how PGPR presence affects Cannabis stalked trichome development and cannabinoid profiles, and how environmental stressors can affect, and even enhance, trichome densities and influence major cannabinoid production, thereby pointing towards avenues for reducing the reliance on synthetic fertilizers during plant production without compromising yield.
... 50 suggested that PGPR have beneficial effects across the entire life cycle of the plants by accelerating the growth rate and shortening the vegetative period. Improvement of cannabis yield by PGPR inoculation has been reported, 35,45,56 and the mechanism of PGPR cannabis growth enhancement depended on nutrient availability as PGPR can facilitate access to nutrients. Some research has reported that nutrient supplementation influences cannabis growth and chemical profiles, but these effects can be positive or negative depending on the amount of applied nutrients. ...
Plant growth-promoting rhizobacteria (PGPR) are a sustainable crop production input; some show positive effects under laboratory conditions but poorly colonize host field-grown plants. Inoculating with PGPR in microbial growth medium (e.g., King's B) could overcome this. We evaluated cannabis plant (cv. CBD Kush) growth promotion by inoculating three PGPR (Bacillus sp., Mucilaginibacter sp., and Pseudomonas sp.) in King's B at vegetative and flower stages. At the vegetative stage, Mucilaginibacter sp. inoculation increased flower dry weight (24%), total CBD (11.1%), and THC (11.6%); Pseudomonas sp. increased stem (28%) dry matter, total CBD (7.2%), and THC (5.9%); and Bacillus sp. increased total THC by 4.8%. Inoculation with Mucilaginibacter sp. and Pseudomonas sp. at the flowering stage led to 23 and 18% increases in total terpene accumulation, respectively. Overall, vegetative inoculation with PGPR enhanced cannabis yield attributes and chemical profiles. Further research into PGPR inoculation onto cannabis and the subsequent level of colonization could provide key insights regarding PGPR-host interactions.
... Pagnani et al. reported that a mixture of four bacterial species applied to the roots of cannabis seedlings in vitro efficiently colonized the entire root system of the plant, favoring plant growth and development in greenhouses as well as accumulation of secondary metabolites. Particularly, two of the main cannabinoids from cannabis, CBD and THC, were significantly improved by endophytic treatment [76]. Nowadays, even though basic information on the diversity and composition of cannabis endophytes has been published, the majority of the works deal with the isolation and identification of microbes rather than their modulating effects on the plant's secondary metabolic pool. ...
Cannabis sativa L. is a plant that humankind has been using for millennia. The basis of its widespread utilization is its adaptability to so many different climatic conditions, with easy cultivability in numerous diverse environments. Because of its variegate phytochemistry, C. sativa has been used in many sectors, although the discovery of the presence in the plant of several psychotropic substances (e.g., Δ⁹-tetrahydrocannabinol, THC) caused a drastic reduction of its cultivation and use together with its official ban from pharmacopeias. Fortunately, the discovery of Cannabis varieties with low content of THC as well as the biotechnological development of new clones rich in many phytochemical components endorsed with peculiar and many important bioactivities has demanded the reassessment of these species, the study and use of which are currently experiencing new and important developments. In this review we focus our attention on the phytochemistry, new matrices, suitable agronomic techniques, and new biological activities developed in the five last years.
... Biofertilizers act in a natural manner by fixing atmospheric nitrogen, solubilizing phosphorus (P), and stimulating plant growth. Since biofertilizers make crops healthy, protect them from pathogens and increase the growth of plants, they can be used to increase crops yields (Fasusi, Cruz, and Babalola 2021;Chojnacka, Moustakas, and Witek-Krowiak 2020;Debasis et al. 2019;Pagnani et al. 2018;Fao 2017). In this context, arbuscular mycorrhizal fungi (AMF) can be used as lowcost and eco-friendly nutrient supplements for the enhancement of plant growth and yield Diagne et al. 2020;Begum et al. 2019;Panneerselvam et al. 2017). ...
Arbuscular mycorrhizal fungi (AMF) symbiosis, which may be found in
almost all naturalistic habitats, perform activities such as nutrition uptake,
stress modulation, growth stimulation, soil structure, and fertility management.
AMF easily takes up phosphorus (P) from the soil and transports it to
the plants. AMF facilitates host plants to grow vigorously under nutrientdeficient
conditions by mediating a series of complex communication events
between the plant and AMF leading to enhanced uptake of soil nutrients
and activation of transporter genes. The fundamental processes of P uptake
and utilization, as well as P transport, regulators, root architecture, metabolic
adaptations, quantitative trait loci, hormone signaling, and microRNA, have
been studied based on molecular and genetic investigations. The current
review provides a comprehensive overview of AMF and its effects on rice
and other plants at various stages of development, as well as the benefits,
applications of AMF, and its interactions between different plant nutrients. It
is identified that the expression of certain phosphate transporter family
genes and P concentration in plant biomass was significantly increased as a
result of the symbiotic relationship between AMF and plants. So, AMF’s role
as a bio-fertilizer has the potential to enhance the plant’s ability to adapt to
changing conditions. AMF-related products for agriculture, horticulture, and
landscaping have gained in popularity as a result of AMF’s vast potential
applicability. We go through recent innovations, developments, and molecular breakthroughs in these areas, as well as the benefits and limitations
of using AMF in the future for long-term crop productivity.
Plant-growth-promoting rhizobacteria (PGPR) influence soil fertility, plant growth, tolerance to abiotic stress, resistance to herbivorous insects, and plant interactions with other organisms. While the effects of PGPR on plant growth, fruit yield, and induced defense responses have been extensively studied, the consistent positive outcomes have fueled rapid expansion in this research field. To evaluate PGPR impacts on plant growth and interactions with phytophagous insects, we conducted a systematic meta-analysis using publications from electronic databases (e.g., PubMed, Web of Science) that reported PGPR effects on plants and insects. Effects were categorized by plant family, PGPR genus, insect feeding guild, and insect–host specialization. Our analysis revealed that PGPR generally enhanced plant growth across most plant families; however, the magnitude and direction of these effects varied significantly among PGPR genera, indicating genus-specific interactions with host plants. When assessing PGPR-mediated reductions in phytophagous insects, we found that Pseudomonas, Rhizobium, and Bacillus exhibited the weakest negative effects on insect populations. PGPR significantly reduced both monophagous and polyphagous insects, with the most pronounced negative impacts on sucking insects (e.g., aphids, whiteflies). This study highlights critical patterns in PGPR-mediated plant growth promotion across taxa and the related differential effects on phytophagous insect activity. These insights advance our understanding of PGPR applications in agroecological production systems, particularly for integrated pest management and sustainable crop productivity.
Currently, large quantities of spent mushroom substrate (SMS) are produced annually. Because SMS has high water retention and nutrients, it has great potential to replace traditional topsoil for raising seedlings in agricultural production. However, few studies have examined the effects of substituting SMS for paddy soil on rice seedling growth and soil nutrients. SMS was mixed with rice soil in different proportions (20%, 50%, and 80%), and chemical fertilizer, organic fertilizer, and peat substrate were added in addition to equivalent nitrogen as a traditional seedling nursery method for comparison. Compared to traditional paddy soil (CK), the seedling qualities of the three SMS ratio treatments were all higher. Adding SMS at different ratios promoted rice seedling root growth, elevated the soluble protein concentration, and amplified the superoxide dismutase (SOD) enzymatic action in rice seedlings. Total porosity and aeration porosity of the soil increased by 17.40% and 32.90%, respectively. Soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) increased by 21.26–118.48%, 50.44–71.68%, and 23.08–80.17%, respectively. Besides, the relative abundance of Bacillus, Bacteroidetes, and other bacteria as well as the abundance of Ascomycota were all significantly increased. Adding 50% SMS increased the abundance of Pseudomonas by 8.42 times. The seedling quality of the 50% SMS treatment was even higher than chemical fertilizer and organic fertilizer treatments, only second to the peat substrate treatment. In summary, partial substitution of paddy soil with SMS can ameliorate substrate properties, improve seedling quality, and increase microbial diversity, indicating the suitability of SMS as a replacement for rice soil in seedling substrates. The 50% SMS ratio is the best. This study provides a basis for SMS to replace traditional rice soil in seedling cultivation.
Graphical abstract
Nigella sativa L. is an aromatic spice, utilized as an original and peculiar flavoring ingredient in a variety of culinary applications and pharmaceuticals. Black seed (Nigella sativa L.) belongs to the family Ranunculaceae. It is an undercultivated crop in Pakistan. The present study was planned keeping in mind sustainable development goals SDG 3 (good health and well‐being) and SDG 15 (life on land). The effects of several rhizospheric bacterial strains and synthetic fertilizers on the development of N. sativa and nutrition were studied using a completely randomized experimental design. For this purpose, plant growth‐promoting effects of different strains (Azospirillum brasilense, Azospirillum lipoferum, and Pantoea agglomerans) and synthetic fertilizers (nitrogen and phosphorus) were assembled to check their effects individually and in combination form. Azospirillum lipoferum and Pantoea agglomerans inoculation significantly enhanced the morphological characteristics of N. sativa, whether applied individually or in combination, with positive effects on seedlings, plant height, number of branches, number of leaves, number of flowers, stamens numbers, follicles number, number of tentacles and seed production. N. sativa plants that were simultaneously inoculated with Azospirillum lipoferum and Pantoea agglomerans showed the highest potential for antioxidant activity, particularly in petroleum ether extracts. In the methanolic extract, a higher amount of radical scavenging was observed as compared to positive and negative control. There was also increase in fat, moisture and carbohydrate contents of the combination inoculated plant. So, from the present study, in Pakistan, the technique is recommended to enhance the yield and nutritional value of N. sativa.
Cannabis sativa L., subsp. ruderalis Janish., ‘Finola’ is a dioecious cultivar of Finnish origin. This cultivar is very interesting because its cultivation cycle lasts less than 3 months. The aim of this study was to define an efficient micropropagation protocol to ensure in vitro multiplication and rooting and in vivo acclimatization. Two different explant sources were tested: seed-derived in vitro explants and nodal segments containing axillary buds from selected mother plants. Shoot proliferation was tested on different growth media enriched with cytokinin alone or cytokinin in combination with auxins. Among all combinations, the best results were obtained by combining the Basal Medium (BM—a Murashige and Skoog modified medium) with sucrose (20 g L⁻¹), thidiazuron (TDZ 0.4 mg L⁻¹), and 1-naphthalenacetic acid (NAA 0.2 mg L⁻¹). Regarding rooting induction, the plants developed an extensive root system under red/blue lights on BM enriched with sucrose (30 g L⁻¹) and indol-3 butyric acid (0.1 mg L⁻¹), which allowed the survival of more than 90 percent of the plantlets once transplanted into the climate-controlled greenhouse.
Using cultivated soils for rice seedlings can reduce the sustainability of arable land and thus giving negative impacts to food production. As a substitute, spent mushroom compost (SMC), which has high water-holding capacity and nutrient content, shows great potentials. To determine the impacts of the proportion of SMC and paddy soil on seedling quality, rhizosphere microbial characteristics, and fungal pathogens in rice seedling substrates, we conducted a 21-day pot experiment for rice seedling under five treatments: CK, 100% paddy soil; R1, 20% SMC and 80% paddy soil; R2, 50% SMC and 50% paddy soil; R3, 80% SMC and 20% paddy soil; and R4, 100% SMC. The results showed that incorporating SMC into the substrate, especially at 50% volume (R2), increased seedling growth and vitality at the seedling growth stage without external fertilization. Moreover, the SMC amendment increased microbial activity and promoted rice seedling recruitment of plant growth-promoting rhizobacteria (PGPR) and fungi (PGPF). In addition, using SMC significantly reduced the abundance of pathogenic fungi, especially Magnaporthe grisea. Overall, the multi-faceted benefits exhibit the strong possibilities of using SMC in sustainable rice productions.
Graphical Abstract
Soil is dynamic living matrix and it is not only a critical resource in
agricultural and food security but it is also towards maintenance of all life
process. Pathogenic microorganisms affecting plant health are a major and
chronic threat to sustainable agriculture and ecosystem stability worldwide.
The chemical fertilizers used in the agriculture to increase yields, kill
pathogens, pests, and weeds, have a big harmful impact on the ecosystem.
Plant growth-promoting rhizobacteria (PGPR) are the rhizosphere bacteria
that can enhance plant growth by a wide variety of mechanisms like
phosphate solubilization, siderophore production, biological nitrogen
fixation, rhizosphere engineering and indirectly by controlling plant
pathogen. Antagonistic bacteria specifically damage pathogens by producing
lytic enzymes, antibiotics and bacteriocins and excluding pathogen from
plant environment by siderophores oriented iron chelation.
In the present study, the essential oils (EOs) of some officinal plants from Abruzzo territory (Italy) were evaluated for their antimicrobial and antioxidant activities and their volatile fraction chemical characterization. The EOs were extracted from Rosmarinus officinalis, Origanum vulgare, Salvia officinalis, Mentha piperita, Allium sativum, Foeniculum vulgare, Satureja montana, Thymus vulgaris and Coriandrum sativum seeds. The antimicrobial activity was screened against thirteen Gram-positive and Gram-negative strains to determine the Minimal Inhibitory Concentration (MIC). The total phenolic content (TPC) and the antioxidant capacity (AOC) were assessed by means of Folin-Ciocâlteu method, and Trolox Equivalent Antioxidant Capacity with 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (TEAC/ABTS), Ferric Reducing Antioxidant Power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays respectively. Among the nine EOs tested, T. vulgaris, S. montana, O. vulgare and C. sativum EOs showed MIC values ranging from 0.625 to 5 μL/mL. The AOC and TPC results for these species were also interesting. The major components for these EOs were thymol for T. vulgaris (44%) and O. vulgare (40%), linalool (77%) for C. sativum, and carvacrol for S. montana (54%). The results allowed the study to establish that these EOs are good candidates for potential application as biopreservatives in foods and/or food manufacture environments.
Background
This study evaluates the influences of bio fertilizers containing mycorrhizal fungi (Glomus fasciculatum, Glomus mosseae) individually or in combination with N-fixer (Azotobacter chroococcum), K solubilizer (Bacillus mucilaginous) and P solubilizer (Bacillus megaterium) on soil fertility and phytochemical levels of spinach. ResultsRoot colonization by mycorrhizal fungi was increased in the presence of bacterial inoculation in comparison to individual inoculation treatments. Inoculation of bio fertilizer containing mycorrhizal fungi and bacterial species considerably augmented the concentration of total phenolic compounds, flavonoids and phenolic acid contents. The 1, 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity of spinach was found to be positively coincided with flavonoid contents, while partially correlated with total phenolic compounds and phenolic acids. Further, the HPLC analysis showed that significantly higher antioxidant activity of spinach was correlated with quercetin contents and chlorogenic acid. Chlorophyll contents were also increased following the bio fertilization treatments. Conclusion
Results revealed that these microbes are useful tool for improving health promoting compounds in spinach.
This study investigated total phenolic and antioxidant activity of five Iranian mint accessions from two different species, Mentha spicata L. (Mzin1, Mzin3 and Mzin8) and M. longifolia L. (Mzin5 and Mzin6). The content of total phenolics (mg tannic acid equivalent per g dry weight of the sample) differed from 50.1 in Mzin3 to 67.2 in Mzin6. The highest percent radical scavenging activity was observed with Mzin6 at all concentrations studied (50, 100, 250, and 500 ppm). Peroxide value of sunflower oil containing Mzin5 and Mzin6 was the lowest among the mint accessions and almost equivalent to that of butylated hydroxytoluene at 200 ppm concentration. In overall, M. longifolia was superior to M. spicata, as determined by two model systems, indicating its potential use as a natural source of dietary antioxidant.
Plant-growth promoting rhizobacteria (PGPR) elicit activation of
phenylpropanoid pathway in plants which leads to phenolics production and
enhanced antioxidant capacity. The purpose of this work was to assess the
antioxidant activity of soybean plants, Glycine max L., inoculated with PGPR
(isolates of Azotobacter chroococcum, Streptomyces sp. and mixture of these)
during plant development, as well as yield of inoculated soybean plants. PGPR
applied in the experiment stimulated flavonoids and isoflavone synthesis,
which enhanced non-enzymatic antioxidant ability of soybean plants. Also,
PGPRs stimulated accumulation of daidzein and genistin in soybean seedlings
(5-fold and 2-fold compared to control values, respectively). The mixture of
PGPRs showed positive impact on antioxidant activity (10-20% higher activity)
and yield components of soybean which proposed this inoculum as possibly
potent bio-fertilizer in soybean production. [Projekat Ministarstva nauke
Republike Srbije, br. TR-31022]
Plant growth promoting rhizobacteria (PGPR) shows an important role in the sustainable agriculture industry. The increasing demand for crop production with a significant reduction of synthetic chemical fertilizers and pesticides use is a big challenge nowadays. The use of PGPR has been proven to be an environmentally sound way of increasing crop yields by facilitating plant growth through either a direct or indirect mechanism. The mechanisms of PGPR include regulating hormonal and nutritional balance, inducing resistance against plant pathogens, and solubilizing nutrients for easy uptake by plants. In addition, PGPR show synergistic and antagonistic interactions with microorganisms within the rhizosphere and beyond in bulk soil, which indirectly boosts plant growth rate. There are many bacteria species that act as PGPR, described in the literature as successful for improving plant growth. However, there is a gap between the mode of action (mechanism) of the PGPR for plant growth and the role of the PGPR as biofertilizer—thus the importance of nano-encapsulation technology in improving the efficacy of PGPR. Hence, this review bridges the gap mentioned and summarizes the mechanism of PGPR as a biofertilizer for agricultural sustainability.
Cannabis sativa L. is an important herbaceous species originating from Central Asia, which has been used in folk medicine and as a source of textile fiber since the dawn of times. This fast-growing plant has recently seen a resurgence of interest because of its multi-purpose applications: it is indeed a treasure trove of phytochemicals and a rich source of both cellulosic and woody fibers. Equally highly interested in this plant are the pharmaceutical and construction sectors, since its metabolites show potent bioactivities on human health and its outer and inner stem tissues can be used to make bioplastics and concrete-like material, respectively. In this review, the rich spectrum of hemp phytochemicals is discussed by putting a special emphasis on molecules of industrial interest, including cannabinoids, terpenes and phenolic compounds, and their biosynthetic routes. Cannabinoids represent the most studied group of compounds, mainly due to their wide range of pharmaceutical effects in humans, including psychotropic activities. The therapeutic and commercial interests of some terpenes and phenolic compounds, and in particular stilbenoids and lignans, are also highlighted in view of the most recent literature data. Biotechnological avenues to enhance the production and bioactivity of hemp secondary metabolites are proposed by discussing the power of plant genetic engineering and tissue culture. In particular two systems are reviewed, i.e., cell suspension and hairy root cultures. Additionally, an entire section is devoted to hemp trichomes, in the light of their importance as phytochemical factories. Ultimately, prospects on the benefits linked to the use of the -omics technologies, such as metabolomics and transcriptomics to speed up the identification and the large-scale production of lead agents from bioengineered Cannabis cell culture, are presented.
Background
Azospirillum spp. are the most studied plant growth-promoting bacteria (PGPB). The genus represents a common model for plant-bacteria interactions. This genus was initially isolated and tested on cereals and was subsequently commercialized.
Aims
Despite claims of plant specificity, particularly towards cereals, data over the past 40 years does not appear to substantiate claims of such specificity/affinity of Azospirillum species. Consequently an evaluation of the specificity/affinity of the genus Azospirillum across all plants, in general, and cereals, in particular, was undertaken.
Results
Although the majority of studies focused on cereals, Azospirillum spp. increase growth of 113 plant species across 35 botanical families, including 14 species of cereals. Amongst Azospirillum spp., several well studied strains have been effective in several plant species, making these organisms potentially valuable for further study.
Conclusions
This review demonstrates that azospirilla are not cereal-specific at the genus and species levels. Azospirillum serves as a general PGPB to every plant species tested so far. Given the paucity of widespread screening, affinity of strains to a plant genotype, cultivar, or plant species cannot be overruled. Definitive conclusions concerning such specificity require molecular and cross-inoculation studies, using various strains of bacteria, and re-isolation after growth of the plants in different plant species. (203 words).
A plant biostimulant is any substance or microorganism applied to plants with the aim to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of its nutrients content. By extension, plant biostimulants also designate commercial products containing mixtures of such substances and/or microorganisms. The definition proposed by this article is supported by arguments related to the scientific knowledge about the nature, modes of action and types of effects of biostimulants on crop and horticultural plants. Furthermore, the proposed definition aims at contributing to the acceptance of biostimulants by future regulations, especially in the EU, drawing the lines between biostimulants and fertilisers, pesticides or biocontrol agents. Many biostimulants improve nutrition and they do so regardless of their nutrients contents. Biofertilisers, which we propose as a subcategory of biostimulants, increase nutrient use efficiency and open new routes of nutrients acquisition by plants. In this sense, microbial biostimulants include mycorrhizal and non-mycorrhizal fungi, bacterial endosymbionts (like Rhizobium) and Plant Growth-Promoting Rhizobacteria. Thus, microorganisms applied to plants can have a dual function of biocontrol agent and of biostimulant, and the claimed agricultural effect will be instrumental in their regulatory categorization. The present review gives an overview of the definition and concept of plant biostimulants, as well as the main categories. This paper will also briefly describe the legal and regulatory status of biostimulants, with a focus on the EU and the US, and outlines the drivers, opportunities and challenges of their market development.
The herb Stevia rebaudiana Bertoni is an important sugar substitute due to the presence of steviol glycosides-mainly stevioside and rebaudioside-A. These compounds possess antioxidant activity with industrial importance. The fungus Piriformospora indica has been used to improve medicinally important biomolecules, growth and secondary metabolite content in plants. The soil bacterium Azotobacter chroococcum has also been reported to possess plant growth promoting ability. The present study was undertaken to test the ability of P. indica (Pi) and A. chroococcum (Az), alone and in combination to improve the growth, antioxidant activity and steviol glycoside (SG) content of in vitro S. rebaudiana plantlets. Inoculation with Pi or Az alone showed enhancement in all these characters compared with non-inoculated plantlets. Combined inoculation with Pi and Az further enhanced these traits.
Background and aims
Gluconacetobacter diazotrophicus is a plant growth-promoting bacteria (PGPB) that colonizes several plant species. Here, we studied the internal colonization of Arabidopsis thaliana tissues by G. diazotrophicus and analyzed its effects on physiology, growth, and activation of plant immune system during such association.
Methods
A. thaliana seedlings were inoculated with G. diazotrophicus and grown in substrate for 50 days. Effects on plant growth were estimated by quantifying number of leaves, leaf area, and fresh and dry weight. Endophytic bacterial population was determined by colony-forming unit (CFU), and its location in plant tissues was assayed by epifluorescence microscopy of red fluorescent protein-labeled bacterium. Whole canopy gas exchange (photosynthesis and transpiration) was determined using a portable photosynthesis system.
Results
G. diazotrophicus efficiently promoted A. thaliana plant growth at 50 days after inoculation. Inoculated plants showed higher whole canopy photosynthesis, lower whole plant transpiration, and increased water-use efficiency. The bacterium colonized preferentially root xylem. The inoculation of plants defective in systemic acquired resistance (SAR)-associated defense revealed that plant immune system plays an important role during the early association stages.
Conclusions
G. diazotrophicus endophytically colonizes A. thaliana roots, promotes plant growth, and increases whole canopy photosynthesis. Our results indicate that A. thaliana is useful for molecular studies of the mechanisms involved in the interaction between plants and PGPB, especially those involving G. diazotrophicus.
This study was conducted to investigate the effects of root inoculations with Bacillus cereus (N(2)-fixing), Brevibacillus reuszeri (P-solubilizing), and Rhizobium rubi (both N(2)-fixing and P-solubilizing) on plant growth, nutrient uptake, and yield of broccoli in comparison with manure (control) and mineral fertilizer application under field conditions in 2009 and 2010. Bacterial inoculations with manure compared with control significantly increased yield, plant weight, head diameter, chlorophyll content, nitrogen (N), potassium (K), calcium (Ca), sulfur (S), phosphorus (P), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) content of broccoli. The lowest yield per plant, plant weight, steam diameter, and chlorophyll content were recorded in the control, but the manure with Bacillus cereus (BC), Rhizobium rubi (RR), and Brevibacillus reuszeri (BR) inoculations increased yield 17.0%, 20.2%, and 24.3% and chlorophyll content by 14.7%, 14.0%, and 13.7% over control, respectively. Bacterial inoculations with manure significantly increased uptake of macronutrients and micronutrients by broccoli. In conclusion, seedling inoculation with BR and especially RR may partially substitute costly synthetic fertilizers in broccoli.
Consumer society, in order to meet the growing
need for food, agricultural land per unit area required to
achieve maximum efficiency and highest quality product. It is
known that the nutrition of the plant is the one of the most
important factors to control agricultural productivity and
quality. Rates of nutrients in the soil affects the quality of yield.
In the permanent agricultural land, the soil will be very poor
in nutrients, as a result, inefficient. Therefore, producers,
fertilize the soil, combat pests, irrigation and process of
agricultural activities to make more efficient to soil.
Fertilization among these activities remains a priority at all
times. Recent studies, however, excessive use of fertilizers is
the need for additional land outside the public and
environmental health of the reported adverse affects. Excessive
fertilization and mindless, but there were soil salinity, heavy
metal accumulation, water eutrophication and accumulation of
nitrate, to consider in terms of air pollution in the air of gases
containing nitrogen and sulfur, giving and can lead to
problems such as the greenhouse effect. In this review, aims to
reveal environmental and health problems caused by improper
fertilization provides recommendation toward solving these
problems.
Plant growth-promoting rhizobacteria (PGPR) are free-living bacteria which actively colonize plant roots, exerting beneficial effects on plant development. The PGPR may (i) promote the plant growth either by using their own metabolism (solubilizing phosphates, producing hormones or fixing nitrogen) or directly affecting the plant metabolism (increasing the uptake of water and minerals), enhancing root development, increasing the enzymatic activity of the plant or "helping" other beneficial microorganisms to enhance their action on the plants; (ii) or may promote the plant growth by suppressing plant pathogens. These abilities are of great agriculture importance in terms of improving soil fertility and crop yield, thus reducing the negative impact of chemical fertilizers on the environment. The progress in the last decade in using PGPR in a variety of plants (maize, rice, wheat, soybean and bean) along with their mechanism of action are summarized and discussed here.
Endophytes are plant-associated prokaryotes that form association with their host plants by colonizing the internal tissues, which has made them valuable for agriculture as a tool in improving crop performance. Although the interaction between endophytes and host plants has not been fully understood, many bacterial species are reported to promote plant growth and the mechanism attributed includes nitrogen fixation, production of growth-promoting substances and increased resistance to pathogens and parasites. They have been reported from numerous plant species including sugarcane. Gluconacetobacter diazotrophicus (syn. Acetobacter diazotrophicus) - sugarcane association represents a model system for monocot-diazotrophic associations. This allows experimentation to answer questions pertaining to their establishment, colonization process, biological nitrogen fixation, growth promotion, etc. The main objective of this review is to summarize the recent works on this bacterium with special emphasis on its interaction with sugarcane. The topics being covered range from the sources of G. diazotrophicus, its classification and characteristics, genetic analysis, in planta colonization and detection, inoculation experiments with suggestions for future research.
The effect of plant growth-promoting rhizobacteria (PGPR) on seed germination, seedling growth and yield of field grown maize were evaluated in three experiments. In these experiments six bacterial strains include P.putida strain R-168, P.fluorescens strain R-93, P.fluorescens DSM 50090, P.putida DSM291, A.lipoferum DSM 1691, A.brasilense DSM 1690 were used. Results of first study showed seed Inoculation significantly enhanced seed germination and seedling vigour of maize. In second experiment, leaf and shoot dry weight and also leaf surface area significantly were increased by bacterial inoculation in both sterile and non-sterile soil. The results showed that inoculation with bacterial treatments had a more stimulating effect on growth and development of plants in nonsterile than sterile soil. In the third experiment, Inoculation of maize seeds with all bacterial strains significantly increased plant height, 100 seed weight, number of seed per ear and leaf area .The results also showed significant increase in ear and shoot dry weight of maize. Keywords—Azospirillum, biofertilizer, Maize, PGPR, Pseudomonas.
Background
Endophytic diazotrophic bacteria colonize several non-leguminous plants and promote plant growth. Different mechanisms are involved in bacteria-induced plant growth promotion, including biological nitrogen fixation (BNF), mineral solubilization, production of phytohormones, and pathogen biocontrol. Herbaspirillum seropedicae is a broad-host-range endophyte that colonizes sugarcane, rice, wheat, sorghum, and maize, and has been used as a biofertilizer. Contrasting results between greenhouse and field experiments have prompted efforts to improve the consistency of the plant response to microbial stimulation.
Aims
The aim of this study was to evaluate the effect of the presence of humic substances on inoculation of maize (Zea mays L.) with H. seropedicae.
Methods
Two experiments were conducted: one in the greenhouse using sand and nutrient solution and the other a field trial in soil with low natural fertility and to which was applied N in the form of urea (50 kg ha−1). In the greenhouse, pre-emerging seeds were inoculated with a solution of H. seropedicae (109 cells mL−1) in the presence of humic substances isolated from vermicompost (10, 20, or 30 mg C L−1); in the field trial, bacteria combined with humate were added as a foliar spray (450 L ha−1).
Results
At early stages (7 and 45 days old) in the greenhouse, the treatment activated plant metabolism including enhancement of plasma membrane H+-ATPase activity, alteration of sugar and N metabolism, and greater net photosynthesis. The number of viable bacterial cells was higher in root tissues when inoculation was in the presence of soluble humic substances. Foliar application of endophytic diazotrophic bacteria and humic substances increased maize grain production 65 % under field conditions. These results show a promising use of humic substances to improve the benefit of endophytic diazotrophic inoculation.
The aims of this study were to investigate the antioxidant (radical scavenging, reducing) and antiproliferative potential of a methanolic extract (ME) of Aloe vera
leaves. DPPH radical scavenging activity was ME—19% (1250 μg/mL); positive controls, ascorbic acid and BHA—24 and 31%, respectively (12.5 μg/mL); 63 and
62%, respectively (50 μg/mL). ABTS+ radical-scavenging activity of 0.046 mM Trolox (TEAC) was equal to that of 1 mg/mL of ME. Protection of supercoiled
pET20b(+) DNA from hydroxyl radicals was as follows: 2000 μg/mL quercetin > 5000 μg/mL ME > 2000 μg/mL ME. Thin layer chromatography (TLC) was used
to qualitatively determine whether the components responsible for antioxidant activity of ME included phenols and anthraquinones. The pre-normalized total
antioxidant activity of ME ranged from 23% (125 μg/mL) to 47% (500 μg/mL) for ME vs. 90% (312.5 μg/mL) for ascorbic acid. The flavonoid and phenolic
contents of ME were 14.1 ± 1.6 CE/g and 38.9 ± 7.6 GAE/g, respectively. The growth inhibition by ME (100 μg/mL) was 32.6, 20.8, 10.6, and -5% in LnCaP, A549,
MG63, and HCT15, respectively. To the best of our knowledge, this is the first reported investigation of antiproliferative activity of an Aloe vera extract in these
human cancer cell lines, whose complex interactions with the ME components translate into the observed differences in growth inhibition and thus warrant further
study.
The interactions between maize, sorghum, wheat and rice plants and Herbaspirillum seropedicae were examined microscopically following inoculation with the H. seropedicae LR15 strain, a Nif⁺ (Pnif::gusA) mutant obtained by the insertion of a gusA-kanamycin cassette into the nifH gene of the H. seropedicae wild-type strain. The expression of the Pnif::gusA fusion was followed during the association of the diazotroph with the gramineous species. Histochemical analysis of seedlings of maize, sorghum, wheat and rice grown in vermiculite showed that strain LR15 colonized root surfaces and inner tissues. In early steps of the endophytic association, H. seropedicae colonized root exudation sites, such as axils of secondary roots and intercellular spaces of the root cortex; it then occupied the vascular tissue and there expressed nif genes. The expression of nif genes occurred in roots, stems and leaves as detected by the GUS reporter system. The expression of nif genes was also observed in bacterial colonies located in the external mucilaginous root material, 8 days after inoculation. Moreover, the colonization of plant tissue by H. seropedicae did not depend on the nitrogen-fixing ability, since similar numbers of cells were isolated from roots or shoots of the plants inoculated with Nif⁺ or Nif⁻ strains.
Microbes in the natural environment are important to maintain physical and biological status of the soil. The long-term use of chemical fertilizers caused several adverse effects to the health and environment and reduced the soil microflora. Nowadays biofertilizers are used as the best alternative to chemical fertilizers. Biofertilizers are considered as a gift of modern agriculture which are eco-friendly and growth-promoting organisms. They enhance the growth of plants by producing growth hormones and by solubilizing nutrients. The present study was aimed to assess the influence of Azophos on growth, physiological, nutrient, and yield parameters of Ocimum basilicum against synthetic fertilizers. The results proved the efficiency of Azophos on growth and yield of Ocimum basilicum.
Of the many medicinal plants with therapeutic potential, Cannabis sativa is, by far, the most promising in the near future for large scale utilization. However, the inherent chemical variability of plant based medicines must be addressed, before cannabis can be incorporated into modern medical practices. This chemical variability can only be controlled and potentially optimized if the underlying causes of the production of therapeutic compounds in cannabis is adequately understood. Many of the medically useful compounds produced by plants are the result of the plant stress response. Although not completely clear, there is a significant body of evidence suggesting a similar role for cannabinoids. Cannabinoids are implicating in both, biotic and abiotic stresses, including thermal, nutrient, and water stress, photoradiation, as well as bacterial and fungal pathogens. This chapter will explore the possible ecological roles of cannabinoids in cannabis and the potential utilization of these roles via biotic or abiotic elicitors.
Harvesting hemp (Cannabis sativa L.) for both stems and seeds is now a common practice in Europe while crop management strategies for dual-purpose hemp cultivation have not been properly addressed so far. In the present study, the effects of planting density and nitrogen fertilization on hemp stem and seed yields were tested with the cultivars Futura 75 and/or Bialobrzeskie in eight contrasting environments (Italy in 2013; Italy and Latvia in 2014; Italy (two sites), Latvia, the Czech Republic, and France in 2015). Stem yield ranged between 1.3 and 22.3 Mg ha⁻¹. The effects of planting density and nitrogen fertilization on stem yield did not interact significantly with each other, or with cultivar and harvest time. Increasing planting density from 30 to 120 plants m⁻² and increasing nitrogen fertilization rate from 0 to 60 kg N ha⁻¹ increased stem yield by 29% and 32%, respectively. Further increase in planting density and nitrogen fertilization did not result in a significant increase in stem yield. Seed yield ranged from 0.3 to 2.1 Mg ha⁻¹. The seed yield was not affected significantly by planting density between 30 and 240 plants m⁻². Although the seed yield showed an increasing trend with increasing nitrogen fertilization, the effects of nitrogen fertilization on seed yield were not statistically significant.
Azospirillum is known for its nitrogen- fi xing and phytohormone production
ability. It is one of very well-studied plant growth-promoting rhizobacteria,
at lab scale to fi eld. None of its species or strain is reported as human or
plant pathogen. It is considered as safest bacteria which can be used as a
biofertilizer at commercial level for several crops, especially cereals or
grasses including wheat and rice which are of economic importance for the
whole world. Some of its species are reported for phosphate-solubilizing
ability and high salt tolerance. Fifteen of its species have been isolated from
variety of hosts and environmental sources; however, a majority have been
reported from plants. There are several reviews available on this organism;
in this chapter, an overview of this organism covering its plant growth promoting
abilities, used as inoculum in lab and fi eld experiments and
used as a commercial biofertilizer for different crops, is provided.
S. Mehnaz
The renewed interest in industrial hemp (Cannabis sativa L.) is due to its large number of applications and for the wide range of agro-environmental conditions under which it can be cultivated. Two-year field experiments (2007 and 2008 growing seasons) were carried out in a Mediterranean environment of central Italy with the aim of assessing the impact of genotype, plant density and N fertilization on hemp yield, in terms of stems, inflorescences and seeds. The treatments consisted in: (a) seven genotypes (Epsilon68, Fedora17, Felina32, Ferimon, Futura75, Santhica27, and Uso31); three plant density (40, 80, and 120 plants m⁻²); two N fertilization levels (50 and 100 kg of N ha⁻¹). Physiological parameters, plant height, stem weight and diameter, inflorescence yield, seed yield and the characteristics of hemp and weed aboveground biomass were recorded. High plant density resulted in shorter plant height compared with low plant density (−41%) as the hemp plants tended to reach the reproductive stage early at high density. At full flowering, stem yield ranged from 3.4 to 8.0 t ha⁻¹ of dry matter and was positively correlated with the duration of vegetative phase, which tended to be high in the intermediate flowering genotypes (Epsilon68, Futura75 and Santhica27). Stem diameter was inversely correlated with plant density (6.7, 5.8 and 5.2 mm at 40, 80 and 120 plants m⁻², respectively). Conversely to stem yield, inflorescence and seed production proved to be higher in the early flowering genotypes (Fedora17, Felina32, Ferimon and Uso31) and increased as plant density increased. High N fertilization level had a positive impact on stems rather than inflorescence and seed yields (on average +28%, +17% and +4% in 100 kg of N ha⁻¹ compared with 50 kg of N ha⁻¹ fertilization level, respectively). Farmers should consider making a dual-purpose production of stems and inflorescences or stems and seeds, even if it is clear that yield is related to the choice of genotype. Further research should be carried out to find various genotypes as well as flexible agronomical practices that are able to improve both traditional (stems) and innovative (inflorescences and seeds) hemp yields under Mediterranean conditions.
In the past two decades, there has been increasing interest in the therapeutic potential of cannabis and single cannabinoids, mainly cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC). THC and cannabis products rich in THC exert their effects mainly through the activation of cannabinoid receptors (CB1 and CB2). Since 1975, 140 controlled clinical trials using different cannabinoids or whole-plant preparations for the treatment of a large number of disorders and symptoms have been conducted. Results have led to the approval of cannabis-based medicines [dronabinol, nabilone, and the cannabis extract nabiximols (Sativex®, THC:CBD = 1:1)] as well as cannabis flowers in several countries. Controlled clinical studies provide substantial evidence for the use of cannabinoid receptor agonists in cancer chemotherapy induced nausea and vomiting, appetite loss and cachexia in cancer and HIV patients, neuropathic and chronic pain, and in spasticity in multiple sclerosis. In addition, there is also some evidence suggesting a therapeutic potential of cannabis-based medicines in other indications including Tourette syndrome, spinal cord injury, Crohn's disease, irritable bowel syndrome, and glaucoma. In several other indications, small uncontrolled and single-case studies reporting beneficial effects are available, for example in posttraumatic stress disorder, attention deficit hyperactivity disorder, and migraine. The most common side effects of THC and cannabis-based medicines rich in THC are sedation and dizziness (in more than 10% of patients), psychological effects, and dry mouth. Tolerance to these side effects nearly always develops within a short time. Withdrawal symptoms are hardly ever a problem in the therapeutic setting. In recent years there is an increasing interest in the medical use of CBD, which exerts no intoxicating side effects and is usually well-tolerated. Preliminary data suggest promising effects in the treatment of anxiety disorders, schizophrenia, dystonia, and some forms of epilepsy. This review gives an overview on clinical studies which have been published over the past 40 years.
Hemp (Cannabis sativa L.) has been a species of value to humans for much of our history given its broad adaptation and multiple uses. The plant is thought to have originated in Eurasia but has been carried to much of the rest of the world, largely for use as a fiber crop. Declining needs for fiber and competition from other plant fiber sources began to reduce demands for hemp. In turn, concern over psychotropically potent forms of hemp (i.e., marijuana) would lead to the crop's effective prohibition during much of the 20th century. Growing recognition of the many uses for hemp beyond the traditional rope, cordage, and canvas has helped revive interest in the crop, and a majority of US states have reduced restrictions to allow research with the plant. Although hemp now appears on the verge of returning to favor in the United States, there will be much to learn to make it a viable crop competitive with other commodities. Variety and photoperiodicity, site suitability, end use (grain, fiber, or dual purposes) and management, and the interactions of these factors will have a strong impact on crop productivity and suitability for post-harvest use. In addition, the harvest and processing technologies (particularly for fibers and essential oils) that are needed to optimize the plant's value are limited or lacking in the United States. Disease and pest issues are often considered of little concern for hemp, but these likely will grow as the plant's range expands. Opportunities for hemp have increased with the recognition that the crop offers growing and diverse uses for not only its fibers, but for its seed grain and essential oils as well. Several studies indicate that hemp grains are nutritious as feed and food additives and its essential oils are of interest given a number of pharmacologically beneficial properties. Although full of promise given its numerous potential benefits and uses, building markets for these products will be a critical (and likely slow) part of hemp's development into a useful agronomic species for US growers.
The aim of this study was to characterize the polyphenolic compounds and antioxidant activity of cold-pressed seed oil from Finola cultivar of industrial hemp (Cannabis sativa L.). Several methodologies have been employed to evaluate the in vitro antioxidant activity of Finola hempseed oil (FHSO) and both lipophilic (LF) and hydrophilic fractions (HF). The qualitative and quantitative composition of the phenolic fraction of FHSO was performed by HPLC analyses. From the results is evident that FHSO has high antioxidative activity, as measured by DPPH radical (146.76 mmol of TE/100 g oil), inhibited β-carotene bleaching, quenched a chemically generated peroxyl radical in vitro and showed high ferrous ion chelating activity. Reactivity towards 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical cation and ferric-reducing antioxidant power values were 695.2 µmol of TE/100g oil and 3690.6 µmol of TE/100 g oil respectively. FHSO contains a significant amount of phenolic compounds of which 2780.4 mg of quercetin equivalent/100 g of total flavonoids. The whole oil showed higher antioxidant activity compared with LF and HF. Our findings indicate that the significant antioxidant properties shown from Finola seed oil might generally depend on the phenolic compounds, especially flavonoids, such as flavanones, flavonols, flavanols and isoflavones.
Auxin production by Azospirillum is believed to play a major role in the observed plant growth promoting effect. By using different genetically modified strains, the contribution of auxin biosynthesis by A. brasilense in altering root morphology was evaluated in a plate assay. Inoculation with the wild type strains A. brasilense Sp245 and Sp7 resulted in a strong decrease in root length and increase in root hair formation. This effect was abolished when inoculating with an ipdC mutant of A. brasilense. The ipdC gene encodes a key enzyme in the IPyA pathway of IAA synthesis by A. brasilense. On the other hand, the observed auxin effect was further enhanced by adding tryptophan, a precursor of IAA, to the plates and could be mimicked by replacing the Azospirillum cells by a particular concentration of IAA. Furthermore, particular mutants (rpoN, scrp) and transconjugants (extra copy of ipdC) of A. brasilense were tested in the plate assay. Together, these results confirm the important role of IAA produced by Azospirillum in altering root morphology and illustrate the power of combining genetic tools and bioassays to elucidate the mechanism of a beneficial Azospirillum-plant interaction.
Background: Gluconacetobacter diazotrophicus is a nitrogen-fixing bacterium initially isolated from sugarcane plants. Endophytic diazotrophs have the potential to fix nitrogen, but the extent of nitrogen fixation is variable and is dependent on the sugarcane genotype and other factors. Exploration of colonization of G. diazotrophicus in other plant species will provide a possibility for the development of nitrogen fixation potential in new host plants. Aims: The aim of the present study is to measure the efficiency of G. diazotrophicus colonization in different sorghum genotypes, which is an important precondition for substantial nitrogen fixation in sorghum plants. Methods: Using root-dip inoculation, G. diazotrophicus wild-type PAL5 was introduced into five grain and two sweet sorghum genotypes. The bacterium colonization in sorghum plants was assessed by the polymerase chain reaction using specific DNA primers to G. diazotrophicus, by analyzing and visualizing the expression of reporter gene uid that marked G. diazotrophicus and by reisolating the bacterium from plant tissues. The sugar content of each sorghum genotype was also measured. Results: G. diazotrophicus was detected in all sorghum genotypes tested, and the bacterium was detected in roots, stems, and leaves of sorghum genotypes via polymerase chain reaction (PCR) analysis. Analysis of the uid reporter gene expression and visualization of embedded samples also indicated full colonization of the bacterium in sorghum plants. The colonization efficiency varied among different plant genotypes and organs, with the number of bacteria ranging from 1.08 × 102 to 7.16 × 103 per g fresh tissue. Colonization of the bacterium was higher in sweet sorghum genotypes than in grain genotypes, and a positive correlation (r = 0.82, p = 0.025) was found between sucrose content of the plants and bacterium colonization efficiency. Conclusion: The nitrogen-fixing bacterium, G. diazotrophicus, can be introduced into different types of sorghum, and the bacterium can be detected in different organs of the plants. Successful and high levels of colonization are an important step to further explore this bacterium for biological nitrogen fixation in sorghum.
Products of browning reaction of glucosamine were prepared from glucosamine-HCl by incubating it at 37°C for 0-30 days, and the antioxidative activity, reducing power, degree of browning, aminosugar contents, pH, moisture and total nitrogen contents of the products were measured. In addition, the brown products prepared from glucosamine by incubation at 37°C for 0, 15 and 30 days were fractionated by gel filtration using Sephadex G-15, and the antioxidative activity, reducing power, degree of browning and pH of each fraction were also measured.
The results obtained were as follows:
1) When white powder of free glucosamine was allowed to stand for 3 days at 37°C, it transformed to a brown paste.
2) The strongest antioxidative activity was observed in the product obtained after incubation between 20 and 30 days.
3) The increase in antioxidative activity of the products of browning reaction was accompanied by the increase in the degree of browning.
4) The brown products prepared from glucosamine by long incubation were fractionated into fractions according to their molecular weights.
Antioxidative activity was detected in the fractions corresponding to intermediate molecular weight.
The objective of this study was to determine the seed chemical composition of ten industrial hemp cultivars grown in Québec. The fatty acid and tocopherol composition, as well as the concentrations of crude protein, oil, ash, cellulose, hemicellulose and lignin were quantified. The seed oil concentration varied between 269 and 306 g/kg, while the crude protein concentration ranged between 238 and 280 g/kg. The hemp seed oil is mainly composed of unsaturated fatty acids, and the dominant fatty acids are linoleic acid (597 g/kg) and α-linolenic acid (170 g/kg). For all ten cultivars, γ-tocopherol was present at a much higher concentration than δ-tocopherol (2481 vs. 774 μg/g). Out of the ten cultivars analyzed, Anka was the richest in phenolics (5.16 g/100 g), whereas CRS-1 had the lowest phenolic content (1.37 g/100 g). Seed ash concentration ranged between 51 and 58 g/kg, while neutral detergent fibre and acid detergent fibre concentrations ranged between 327 and 388, and 259 and 298 g/kg, respectively. In conclusion, our results reveal noticeable differences among cultivars in terms of the essential fatty acid, oil, protein, and antioxidant content of industrial hemp seed. Collectively, this study suggests that the seed of Canada-grown hemp is a balanced health product.
Nitrogen trials were carried out on hemp crops grown in Ireland over a 3 year period to identify nitrogen fertilization strategies which optimize the greenhouse gas (GHG) and energy balances of hemp crops grown for biomass. Nitrogen rates up to 150 kg N ha−1 were used in the study. Yield increased with nitrogen rate up to 120 kg N ha−1 for early (Ferimon), mid (Felina 32) and late maturing (Futura 75) varieties. Variety had a significant effect on yield with yields increasing with maturation date. In 2 years of the study, certain application rates of nitrogen were applied either at sowing, at emergence, after emergence or split between these dates to determine if nitrogen rates could be reduced by delaying or splitting the applications. The application of nitrogen at times later than sowing or in splits during the early part of the growing season had no significant effect on biomass yield compared with the practice of applying nitrogen at the time of sowing. Late applications of nitrogen reduced leaf chlorophyll content and height early in the growing season. Later in the growing season, there was no difference in height between treatments although the highest concentrations of chlorophyll were found in the leaves of the late application treatment. Nitrogen rate and the timing of nitrogen application had no effect on plant density. Biomass yield, net energy and net GHG mitigation increased up to an application rate of 120 kg N ha−1, this result was independent of soil type or soil nitrogen level. Net GHG and energy balance of hemp crops grown for biomass are optimized if late maturing varieties are used for biomass production and a nitrogen rate of 120 kg ha−1 is applied at sowing.
Endophytic bacterial communities of tomato leaves were analyzed by 16S rDNA pyrosequencing and compared to rhizosphere communities. Leaf endophytes mainly comprised five phyla, among which Proteobacteria was the most represented (90%), followed by Actinobacteria (1,5%), Planctomycetes (1,4%), Verrucomicrobia (1,1%) and Acidobacteria (0,5%). Gammaproteobacteria was the most abundant class of Proteobacteria (84%), while Alphaproteobacteria and Betaproteobacteria represented 12% and 4% of this phylum, respectively. Rarefaction curves for endophytic bacteria saturated at 80 OTUs, indicating a lower diversity as compared to rhizosphere samples (>1,700 OTUs). Hierarchical clustering also revealed that leaf-endophytic communities strongly differed from rhizospheric ones. Some OTUs assigned to Bacillus, Stenotrophomonas and Acinetobacter, as well as some unclassified Enterobacteriaceae were specific for the endophytic community, probably representing bacteria specialized in colonizing this niche. On the other hand, some OTUs detected in the leaf endophytic community were also present in the rhizosphere, probably representing soil bacteria that endophytically colonize leaves. As a whole, this study describes the composition of the endophytic bacterial communities of tomato leaves, identifying a variety of genera that could exert multiple effects on growth and health of tomato plants. This article is protected by copyright. All rights reserved.
The effects of single inoculation and co-inoculation of two plant growth-promoting rhizobacteria (PGPR) (Pseudomonas fluorescens, Azospirillum brasilense) on growth and essential oil (EO) composition and phenolic content were evaluated in marigold (Tagetes minuta). Plant growth parameters (shoot fresh weight, root dry weight, leaf number, node number) were measured. EO yield increased 70% in P. fluorescens-inoculated and co-inoculated plants in comparison with control (non-inoculated) plants, without altering EO composition. The biosynthesis of the major EO components was increased in the inoculated plants. Shoot fresh weight and EO yield were significantly higher in P. fluorescens-inoculated and in co-inoculated plants than in control plants. The total phenolic content was 2-fold higher in singly-inoculated or co-inoculated treatments than in controls. In view of the economic importance of monoterpenes and phenolic compounds for a variety of applications in the food and cosmetic industries, P. fluorescens and other PGPR have clear potential for improving the productivity of cultivated aromatic plants. Better understanding of the processes that affect the accumulation of secondary metabolites will lead to increased yields of these commercially valuable natural products.
During the last 35 years of studies of Azospirillum–plant interaction, over 20 proposals were suggested for the mechanism of action by which Azospirillum spp., the most intensively studied plant growth-promoting bacteria, enhances plant growth. The proposals include a single phytohormone activity, multiple phytohormones, nitrogen fixation, assortments of small-sized molecules and enzymes, enhanced membrane activity, proliferation of the root system, enhanced water and mineral uptake, mobilization of minerals, mitigation of environmental stressors of plants, and direct and indirect biological control of numerous phytopathogens. By volume, the largest number of published information involves hormonal activities, nitrogen fixation, and root proliferation. After analyzing the accumulated knowledge, it was concluded that this versatile genus possesses a large array of potential mechanisms by which it can effect plant growth. Consequently, this review proposes the “Multiple Mechanisms Theory,” based on the assumption that there is no single mechanism involved in promotion of plant growth by Azospirillum, but a combination of a few or many mechanisms in each case of inoculation. These may vary according to the plant species, the Azospirillum strain, and environmental conditions when the interaction occurred. The effect can be cumulative, an “additive hypothesis” (proposed before), where the effects of small mechanisms operating at the same time or consecutively create a larger final effect on plant. Additionally, the observed effect on plant growth can be the result of a tandem or a cascade of mechanisms in which one mechanism stimulates another, yielding enhanced plant growth, such as the plausible relations among phytohormones, nitric oxide, membrane activities, and proliferation of roots. Finally, the growth promotion can also be a combination of unrelated mechanisms that operate under environmental or agricultural conditions needed by the crop at particular locations, such as mitigating stress (salt, drought, toxic compounds, adverse environment), and the need for biological control of or reducing pathogenic microflora.
Auxin production by Azospirillum is believed to play a major role in the observed plant growth promoting effect. By using
different genetically modified strains, the contribution of auxin biosynthesis by A. brasilense in altering root morphology
was evaluated in a plate assay. Inoculation with the wild type strains A. brasilense Sp245 and Sp7 resulted in a strong decrease
in root length and increase in root hair formation. This effect was abolished when inoculating with an ipdC mutant of A. brasilense.
The ipdC gene encodes a key enzyme in the IPyA pathway of IAA synthesis by A. brasilense. On the other hand, the observed
auxin effect was further enhanced by adding tryptophan, a precursor of IAA, to the plates and could be mimicked by replacing
the Azospirillum cells by a particular concentration of IAA. Furthermore, particular mutants (rpoN, scrp) and transconjugants
(extra copy of ipdC) of A. brasilense were tested in the plate assay. Together, these results confirm the important role of
IAA produced by Azospirillum in altering root morphology and illustrate the power of combining genetic tools and bioassays
to elucidate the mechanism of a beneficial Azospirillum-plant interaction.
Within a given plant population, the concentration of any constituent is expected to vary within a certain bandwidth. To test the distribution of Δ9-tetrahydrocannabinol (THC) in hemp populations, a number of single plants were taken from populations of five well-known hemp accessions (Fasamo, Beniko, Bialobrzeskie, Félina 34, Kompolti) and a Hungarian provenance. The quantitative analysis of single plants delivered a set of 30–61 THC and Cannabidiol (CBD) values for each of the six hemp accessions under consideration. The distribution of THC within a number of hemp plants often shows no Gaussian distribution, the different varieties have quite characteristic distributions of THC. Most single-plant values are close together, the variation, however, differing from variety to variety. In addition, single plants are found with THC values far outside this bandwidth.
Previous studies have shown that Azospirillum or its culture filtrates induce root hairs in wheat seedlings to branch; this phenomenon is influenced by the bacterial genome at the strain level and by the plant genome at the cultivar level. Strain Sp245 caused most branching of root hairs; between wheat cultivars frequency of branching increased in the following order: cv. Tobari, cv. Tonari, cv. BH1146, cv. Lagoa. Similarly, plant growth response to inoculation with Azospirillum, measured in mature plants, increased in the same order, suggesting that both phenomena (root hair branching and plant growth response) have a similar basis. In this study, the "branching substance" present in Azospirillum culture filtrate was found to be thermostable at 100 °C, removed by dialysis, present in the acidic nonpolar fraction of the cell-free extract, and co-chromatographed with authentic indole acetic acid on thin-layer chromatograms. Purified indole acetic acid caused branching of root hairs similar to that caused by the Azospirillum culture filtrates. Susceptibility of wheat cultivars to indole acetic acid induced branching increased in the order: cv. Tobari, cv. Tonari, cv. BH1146, cv. Lagoa. Of five strains examined, strain Sp245 produced the most indole acetic acid in culture in the presence of tryptophan. The presence of indole acetic acid was confirmed by gas chromatography – mass spectrometry.
This is the third in a series of “Hemp production notes,” which focuses on the unique challenge of growing hemp at high latitudes in the European Community. This paper briefly reviews the historical considerations of hemp in Finland, addresses some of the problems inherent at high latitudes and identifies specific market potentials for the Nordic production of hemp seed as an industrial crop.