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Salicylic acid priming before and after accelerated aging process increases seedling vigor in aged soybean seed
Abstract
Seed vigor in soybean (Glycine max (L.) Merr.) declines under environmental stresses, and seed shows signs of aging. The aging effects may be alleviated, however, by seed priming with certain chemicals, such as salicylic acid (SA). The objective of this study was to investigate the effects of SA priming on activities of certain enzymes and lipid peroxidation in soybean seedlings under accelerated aging (AA) process. A factorial, completely randomized design with three replicates was used. Different aging durations (48 h and 72 h), SA priming solutions (0, 300 and 600 μM) and priming times (before aging, after aging and both before and after aging, i.e., double priming) were the experimental factors. Increasing aging duration significantly increased mean emergence time (MET) but decreased carotenoid content. Nonetheless, SA solution mitigated the adverse effect of seed deterioration on germination-related traits by increasing enzyme activity and reducing malondialdehyde (MDA) content, especially under double priming. A strong negative correlation (r = – 0.99**) was found between MDA content and chlorophyll a and chlorophyll b content. By contrast, the correlation between MDA content and MET (r = 0.95**) was found to be positive. The results suggested that double SA priming was an appropriate practical technique to improve seedling establishment from aged soybean seed.
... These compounds are associated with seed longevity and energy production during germination and maintaining their levels improved the germination variables after AA treatment. Use of different seed treatments through improving biochemical content and antioxidative enzyme activites in seeds increased germination levels in aged seeds in many crop species (Roach et al. 2018;Ardebili et al. 2019;Zhou et al. 2019;Nazari et al. 2020;Xia et al. 2020). Seed treatments trigger different metabolic processes, such as conversion of fatty acids to sugars, which improved availability of sugars for energy production during germination, and increased GP in aged soybean seeds, but not in fresh seeds (Zhou et al. 2019). ...
... While CaCl 2 treatment reduced MDA and H 2 O 2 contents and SOD activity, it increased POD activity in both cultivars compared to the AA treatment. Different reports indicated that MDA and/or H 2 O 2 contents increased due to aging in sunflower, soybean, cowpea, watermelon seeds (Hsu and Sung 1997;Bailly et al. 1998;Kibinza et al. 2011;Arun et al. 2017;Nazari et al. 2020;Xia et al. 2020;Arab et al., 2022). Different seed treaments were effective in reinvigoration of aged seeds, as determined by their increased germination levels and reduced MDA and H 2 O 2 contents. ...
... However, there were also differences for enzyme activities for different treatments in different speices. Nazari et al. (2020) reported that salicylic acid treatments increased SOD, but decreased POD activity after AA treatment in soybean seeds. SOD acticity increased after ascorbic acid and glutathione treatments in soybean (Xia et al. 2020), but SOD activity decreased with the same treatments in our study. ...
The viability of safflower (Carthamus tinctorius L.) seeds decreases with aging and reduction in vigor has detrimental effects on agricultural production. Seed treatments are economical and effective techniques to the alleviate the effects of aging. The objective of the research was to study the effects of seed treatments after accelerated aging (AA) on germination variables, biochemical content and antioxidant enzyme activities in safflower seeds. Seeds of two safflower cultivars were subjected to AA treatment at 43 ± 1°C for 72 h, and after the AA treatment, aged seeds were treated with glutathione, ascorbic acid and calcium chloride (CaCl2). Accelerated aging reduced germination and normal seedling percentage, soluble sugars, protein, tocopherol and peroxidase activity. Seed treatments significantly improved germination and normal seedling percentage , and decreased reducing sugars, free fatty acids, free amino acids, malondialdehyde, hydrogen peroxide and superoxide dismutase activity, though extent of these changes was different between the treatments and cultivars. Correlation and principal coordinate analysis revealed significant correlations between germination variables, biochemical content and antioxidant enzyme activities and CaCl2 treatment differed from the other treatments. Our results show that ascorbic acid, glutathione and CaCl2 treatments after AA treatment alleviate aging damage, and CaCl2 treatment was more effective than the other treatments for reducing aging damage and improving vigor in safflower seeds.
... Several seed priming techniques are used currently, such as water (hydro-priming), osmotic solutions (osmo-priming), inorganic salts (halo-priming), matric materials (matric-priming) and various natural extracts (live or decomposition materials from plant or animal parts) to enhance seed and seedling vigour. In previous studies, various solutions were suggested as priming agents for soybean such as polyethylene glycol (PEG) [15], salicylic acid (SA) [16], potassium nitrate (KNO 3 ), potassium chloride (KCl) and ascorbic acid (ASA) [17]. Although the above-mentioned chemicals have shown a positive effect, concerns of its use on the environment and the search for user-friendly seed priming agent for sustainability is on-going. ...
... The current study proved that priming with HA for 5 h increased germination percentage, seedling quality and field establishment especially in water shortage conditions particularly when minimally aged seeds (due to deterioration in storage) were used. Although literature has shown a positive effect of various other priming agents on the improvement of soybean seeds [15][16][17], to date, there is no record of improvement for seeds that has been stored for more than six months. Additionally, all the priming agents used are chemical in nature, hence the use of humic acid may serve as an environmental and user-friendly priming agent. ...
Soybean seed vigour declines with increase in storage duration, due to ageing, which can be alleviated through seed priming. The objective of this study was to investigate the effects of Humic acid (HA) priming on germination, vigour and seedling performance under laboratory and greenhouse conditions with two soil moisture level [50% and 80% field capacity (FC)]. Seeds stored for 12 months having 60% germination were primed either with 0.2 g/L HA solution or distilled water (hydro-primed) at 25 °C for 1, 3, 5 and 7 h. Non-primed dry seeds were used as control, giving nine treatment combinations. Various germination traits [mean germination time (MGT), final germination percentage (FG%), germination rate index (GRI), seedling emergence percentage (SEP)], mean emergence time (MET), seedling quality traits [seedling vigor index (SVI), shoot length, root length, root volume], antioxidant enzyme activities [catalase (CAT), peroxidase (POD)], lipid peroxidation [malondialdehyde (MDA)] and electrical conductivity (EC) were determined. A germination test in the laboratory was conducted as single factor (nine priming treatments), while the greenhouse experiment was conducted as two factors [2 soil moisture level (50 and 80% FC) and 9 priming treatments]. The results indicated that seeds primed with HA for 5 h was able to reinstate the CAT activities (25%), POD activities (50%) and reduced EC (51%) and MDA content (40%) compared with non-primed seeds, reduced the MET (from 4.3 to 3.5 days), increased FG% (from 62 to 71%), GRI (15.6–21.1) and SEP (from 35 to 54%) and (from 60 to 72%) at 50% FC level and 80% FC level, respectively. A strong negative correlation (r = −0.80 **) was found between MDA content and GRI, while CAT and POD activities had positive correlation with GRI r= 0.67 ** and r = 0.56 **, respectively. Thus, priming with 0.2 g/L HA for 5 h improved the vigour of minimally deteriorated soybean seeds resulting in increased emergence with more uniform field establishment.
... The successful establishment of normal seedlings, especially under adverse environmental conditions, is directly dependent on the balanced synthesis of plant hormones, such as abscisic acid (ABA), gibberellic acid (GA), and salicylic acid (SA) (Gharbi et al. 2018;Shatpathy et al. 2018). These phytohormones, considered anti-stress compounds, are endogenously synthesized in plants to activate the defense functions (Mohaddes Ardebili et al. 2019) and to mitigate lipid peroxidation (Nazari et al. 2020). However, intensifying environmental stresses may reduce the efficiency of defense mechanisms during cell division-related processes, such as protein synthesis, and eventually lead to germination failure or the emergence of abnormal seedlings (Seyyedi et al. 2015). ...
... To alleviate the effects of environmental stresses on germination, exogenous application of plant hormones is considered one of the most widely used techniques (Eisvand et al. 2010;Hajiabbasi et al. 2020). Phytohormonal priming with ABA, GA (Mohaddes Ardebili et al. 2019), and SA (Nazari et al. 2020) can accelerate cell division and differentiation of the embryonic tissue by reducing ionic toxicity and stabilizing membrane integrity. ...
The expression of genes that control germination-related processes in corn (Zea mays L.) is influenced by environmental factors. Germination of seeds may be facilitated by hormonal priming. The purpose of this investigation was to quantify the effects of different germination temperatures [(5, 10, 15, 20, 25, 30, 35, and 40°C), NaCl-induced stress (0, −0.4, −0.8, and −1.2 MPa), and priming solutions (control, hydropriming, abscisic acid (ABA), gibberellic acid (GA), and salicylic acid (SA)] (Experiment 1). Effects of germination temperatures, PEG 6000-induced stress (0, −0.4, −0.8, and −1.2 MPa), and priming solutions were also evaluated separately (Experiment 2). In both cases, a completely randomized design with four replications was used. Increasing temperatures from 5 to 25°C gradually improved germination percentage and rate, whereas temperatures > 25°C decreased these indices. After imposing drought (PEG 6000-induced stress) or salinity (NaCl-induced stress) treatments, hormonal priming caused germination to occur at a lower base temperature, compared with the non-priming treatment. However, the effect of hormonal priming was dependent on temperature. At sub-optimal temperatures (< 25°C), the highest germination percentage and rate were recorded after GA priming. At above-optimal temperatures (> 25°C), ABA priming resulted in the highest germination percentage and rate. Moreover, hydrothermal time constant decreased in hormone-treated seeds. Based on coefficient of determination (R²) and root mean square error (RMSE), a dent-like model predicted cardinal temperatures more accurately than a beta model did. Generally, GA-, SA-, and ABA-priming were recommended under sub-optimal, optimal, and above-optimal temperatures, respectively.
... The production of ROS is one of the physiological results causing seed degradation [15,16]. These free radicals may adversely affect the function of macromolecules and enzymatic activity by inducing enzymatic lipid peroxidation [13,17,18]. ...
... Catalase is an enzyme that catalyzes the separation of H2O2 to H2O and O2 and does not need any reducing agent [35]. The CAT activities after AA observed in this study was similar to results of the previously reported studies for cotton [12], maize [36], onion [8] Jatropha curcas [7] and soybean [18] seeds. In okra seeds AA at 40 °C for 96 and 192 h of aging reduced CAT activity compared to control [28]. ...
Safflower is an important oleiferous crop species in the world. Aging tests are used to simulate cell damage occurring during the long term storage of seeds. In the present study, accelerated aging (AA) test was employed to investigate response of antioxidant enzymes in safflower. Four genotypes of safflower, previously classified as aging resistant (Bayer-6 and Bayer-12) and sensitive (Olas and Linas) based on AA test, were used as seed materials and AA treatments at 43 °C consisted of 5 different times (0, 48, 72, 96 and 120 h). Variance analysis were used and means were separated according to significance levels, and correlations were calculated between hydrogen peroxide (H2O2) content, superoxide dismutase (SOD) and catalase (CAT) activities. The H2O2 content, CAT, SOD and peroxidase (POD) activities were measured in control and AA treated seeds. Genotype, time and genotype x time interactions were all significant. While H2O2 content and SOD activity increased with AA time, CAT activity decreased in all genotypes throughout the experiment. POD did not show regular increase or decrease, its activity was specific to genotypes and time. Correlations between CAT activity and H2O2 content were significant negative for all genotypes, but between SOD activity and H2O2 content was positively correlated in AA treated seeds.
... These findings align with earlier research on castor and soybean, where similar improvements in germination traits were observed (29). The beneficial effects of salicylic acid (SA) on seed germination may be attributed to its role in reducing abscisic acid (ABA) levels, which in turn prevents the decline of essential growth hormones such as cytokinin and indole-3-acetic acid (IAA) under water stress, as reported in wheat (30). ...
... The application of salicylic acid priming with concentrations of 0, 300, and 600 μM in aged soybean seeds effectively counteracted the negative impact of seed deterioration on germination-related characteristics. This was achieved through the enhancement of enzyme activity and the reduction of malondialdehyde (MDA) content (Nazari et al. 2020). It has been demonstrated through research that NO priming improves germination rates and antioxidant capabilities in degraded oat seedlings, hence mitigating the effects of aging-related impairments (Penfield 2017;Yan and Mao 2021;Mao et al. 2018). ...
The shelf life of seeds is determined by their inherent aging and loss of viability during storage. Enhancing longevity is crucial for long-term seed preservation (germplasm conservation) and agricultural development as it is correlated with effective seed germination. Protective mechanisms are affixed to orthodox seeds throughout the maturation drying process, preventing the seeds from deteriorating. These consist of the accumulation of antioxidants, non-reducing sugars (RFOs), heat shock proteins, hormones, and chemical protectants, as well as protective proteins, including numerous late embryogenesis proteins. One way to maintain the potential of seed viability is through the cytoplasm's ability to transition from a liquid to a glassy state based on the moisture level of the seeds. Since cell metabolism has stopped, the cytoplasm of the dried seeds maintains its glassy state and ensures the integrity of its constituent parts. Even with low moisture content and glassy cytoplasm, seeds undergo aging due to reactive oxygen species produced by the oxygen in the storage environment. Research on phytohormones, specifically auxins, gibberellins, and abscisic acid, has identified new seed lifespan regulators. Additionally, phytohormones have emerged as significant endogenous seed longevity controllers. To sustain the viability and quality of seeds, strategies that consider the complex interactions between genes, pathways, hormone signaling, and downstream systems related to seed longevity must be understood. The reasons for deterioration and seed death are unknown, as aging is a complex biological process involving a network of physiological, biochemical, molecular, and metabolic processes. This review provides a detailed description of the mechanism and effect of seed aging, as well as the role of phytohormones with positive and negative regulators in seed germination, thereby facilitating future research on the crosstalk of phytohormones in seed germination.
... These findings align with earlier research on castor and soybean, where similar improvements in germination traits were observed (29). The beneficial effects of salicylic acid (SA) on seed germination may be attributed to its role in reducing abscisic acid (ABA) levels, which in turn prevents the decline of essential growth hormones such as cytokinin and indole-3-acetic acid (IAA) under water stress, as reported in wheat (30). ...
Castor is an essential nonedible oilseed crop with significant applications in the cosmetic and chemical industries. It is cultivated primarily in rainfed regions, where drought is a common abiotic stress factor. Seed germination, the critical initial stage, is particularly affected by drought. Seed priming with radical scavenging chemicals such as salicylic acid, melatonin, hydrogen peroxide and ascorbic acid has been explored to increase germination under water deficit conditions. This study aimed to evaluate the effects of different concentrations of these chemicals on the physiological and antioxidant enzyme activities of castor under drought stress. Two water regimes were applied in the study. Among the treatments, seed priming with 80 ppm salicylic acid significantly improved key parameters, including the germination % (71 %), speed of germination (4.1 %), vigour index (3141), chlorophyll content (28.3 SPAD units) and relative water content (63 %). It also increased the antioxidant enzyme activities such as CAT, POD, SOD and APX, along with the overexpression of the drought-responsive gene RCECP63 under water deficit conditions. These findings highlight that seed priming, particularly with salicylic acid, offers a promising strategy to enhance castor resilience under prolonged drought stress, providing a practical approach for improving crop performance in drought-prone regions.
... Instead, it may also allow the growtharrested seeds to reinforce their capacity to mount adaptive defence responses to withstand environmental stress during phase II of seed germination [37]. Through seed priming, the low-vigor seeds of various plants could be revitalized [120,121]. Primed seeds frequently show enhanced antioxidant enzymatic activities, such as catalase, peroxidase, ascorbate peroxidase, and superoxide dismutase, as well as storage protein solubilization [122]. This observation is unsurprising, given that the rehydration process during seed priming induces the accumulation of ROS and lipid peroxidation. ...
Seeds are essential for plant reproduction, ensuring species survival and dispersal while adapting to diverse environments throughout a plant’s life. Proteomics has emerged as a powerful tool for deciphering the complexities of seed growth, germination, and stress responses. Advanced proteomic technologies enable the analysis of protein changes during germination, dormancy, and ageing, enhancing our understanding of seed lifespan and vitality. Recent studies have revealed detailed insights into metabolic processes and storage protein profiles across various plant species. This knowledge is crucial for improving seed storage, conserving quality, and maintaining viability. Additionally, it contributes to sustainable agriculture by identifying stress-responsive proteins and signalling pathways that can mitigate stress and enhance farming practices. This review highlights significant advancements in seed proteomics over the past decade, discussing critical discoveries related to storage proteins, protein interactions, and proteome modifications due to stress. It illustrates how these insights transform seed biology, boosting productivity, food security, and environmentally friendly practices. The review also identifies existing knowledge gaps and provides direction for future research, underscoring the need for continued interdisciplinary collaboration in this dynamic field.
... Salicylic acid is an autogenous hormone which participates in multiple activities of plants such as seed and fruit yield and quality, seedling vigour, lipid peroxidation, nitrogen metabolism as well as in the defence system of plant for efficient quenching of ROS via antioxidant enzymes (Singh et al., 2016;Nazari et al., 2020). Salicylic acid enhances the ability of plants to tolerate different abiotic stresses by alleviating the development and growth of the plant. ...
... Salicylic acid is an autogenous hormone which participates in multiple activities of plants such as seed and fruit yield and quality, seedling vigour, lipid peroxidation, nitrogen metabolism as well as in the defence system of plant for efficient quenching of ROS via antioxidant enzymes (Singh et al., 2016;Nazari et al., 2020). Salicylic acid enhances the ability of plants to tolerate different abiotic stresses by alleviating the development and growth of the plant. ...
Salinity is a major constraint for mungbean seedlings establishment. Salicylic acid (SA) is an endogenously synthesized signaling compound contributes to regulate physiological processes in plants as well as biotic and abiotic stress responses. Effect of SA seed priming of mungbean in developing resistance under salt stress was investigated. The seeds of mungbean varieties (NM-2016 and NM-20-21) were soaked in 0.01% and 0.02% of SA while, no priming and hydropriming was taken as control. Seeds were sown in washed river sand with two salinity (0, 80 mM NaCl) levels. The results showed that priming with 0.01% SA improved plant height and dry biomass as compared with hydropriming and non-priming plants under salt stress. Meanwhile, 80 mM salt stress notably decreased the concentrations of Ca 2+ , N, P, and K + while Na + and Cl-contents increased in leaves as compared to control plants. But 0.01% SA improved the concentrations of almost all nutrients except Mg 2+ under salt stress as compared to hydropriming and control. Collectively, NM-20-21 variety performed better than that of NM-2016 and seed priming with 0.01 % SA was found more effective in improving growth and nutrient uptake of mungbean seedlings.
... Seedling vigor is a complex interaction between seed germination, emergence, and early growth factors in the context of the interaction between plant genetics and environmental factors [52][53][54][55]. Neonicotinoid-treated corn did not have a significant advantage for vigor in field testing when compared to a fungicide-only treatment using visual scoring [56]. ...
Soybean (Glycine max) is one of the most important oilseed crops grown in North America and a key contributor to the global protein supply. Insect feeding by a major soybean pest, the bean leaf beetle (BLB; Cerotoma trifurcata), can result in economic yield loss if not controlled. The objective of this research was to use unmanned aerial vehicle (UAV) image analysis to compare the agronomic and efficacy traits of two soybean insecticide seed treatments (IST) in locations with BLB feeding. Across the 2018–2023 field trial locations, 29 had low BLB feeding pressure (less than 25% feeding damage to no IST plots) and 31 had high BLB feeding pressure (greater than 25% feeding damage to no IST plots). In low BLB pressure locations, cyantraniliprole and imidacloprid seed treatments had significantly higher BLB efficacy, significantly higher UAV greenness, and significantly higher final yield as compared to no IST. In high BLB pressure locations, cyantraniliprole and imidacloprid seed treatments were significantly better compared to no IST for BLB efficacy, UAV emergence, UAV vigor, UAV greenness, and final yield. In high BLB pressure locations, cyantraniliprole had significantly higher BLB efficacy, significantly better UAV emergence, and significantly higher yield compared to imidacloprid. The cyantraniliprole treatment had a +254.5 kg/ha increase compared to no IST in low BLB pressure locations and a +213.7 kg/ha increase in high BLB pressure locations. The imidacloprid treatment had a +163.4 kg/ha yield increase compared to no IST in low BLB pressure locations and a +121.4 kg/ha yield increase in high BLB pressure locations. The use of UAV image analysis enabled quantification of the effect of BLB feeding on early-season agronomic traits and, when combined with efficacy and final yield data, successfully differentiated the performance of two soybean ISTs in environments with low or high insect pressure.
... Successful planting of normal seedlings, particularly under unfavorable environmental situations, is immediately addicted on the balanced synthesis of plant hormones (Gharbi et al., 2018;Shatpathy et al., 2018). These hormones, which are synthesized endogenously in plants, are considered as defense function compounds (Mohaddes Ardebili et al. 2019) and those that reduce lipid peroxidation (Nazari et al. 2020) in stress situations. External application of plant hormones is one of the most widely used techniques to reduce the effects of environmental stress on germination (Eisvand et al. 2010;Hajiabbasi et al. 2020). ...
The aim of study was to investigate the effects of salicylic acid on germination and seedling parameters of maize cultivars (Zea mays L.) under drought stress conditions. The research was carried out in a growth chamber in a factorial experiment design with four replications in random plots. In this study, three different silage maize cultivars were used (Side, Pehlivan and Burak). Drought conditions were established using Polyethylene glycol-6000 (PEG-6000) at three different levels (0.-0.4 MPa and -0.8 MPa). Salicylic acid applications were calculated at three different doses of 0-0.1-0.2 mM. The parameters examined in Side cultivar gave superior results exposed to drought conditions compared to other cultivars. Differences were determined in the response of maize cultivars to drought stress, and statistically noteworthy diminishes were also observed as the drought level enhanced. It was displayed that salicylic acid applications generally boosted germination and seedling parameters exposed to drought conditions compared to control. The maximum shoot lenght was detected at 0.2 mM SA dose with 2.30 cm but that did not exhibit significant numerical differences. SA applications, on the other hand, did not have an effect on root length. Moreover, the best result of shoot fresh weight was recorded in 0.1 mM SA application, as root fresh weight gave the best in 0.2 mM SA application. Furthermore, when a correlation is made between the specified parameters, the highest relation was markedly positive and linked between GR and GI (r: 0.99, p
... ---It is a good candidate for reducing the toxicity of heavy metals such as chromium (VI). [118,119] ( ...
Biostimulants are one of the most important substancesfor improving productivity, growth and yield of plants as well as heavy metal detoxification, and stimulating natural toxins, controlling pests and diseases and boosting both water and nutrient efficiency. Google Scholar, Science Direct, CAB Direct, Springer Link, Scopus, Web of Science, Taylor and Francis, and Wiley Online Library have been checked. The search was done to all manuscript sections according to the terms "Salicylic acid," "Humic acid," "Fulvic acid," "Biostimulants" and "Plant growth promotion." On the basis of the initial check, Titles and Abstracts were screened on the basis of online literature, and then articles were read carefully. Salicylic acid may have important roles in abiotic stresses such as salinity, drought, cold, heavy metal and heat stresses, and it has been considered an important environmentally-sound agent with tremendous economical benefits and rapid responses. The positive effects of the application of salicylic acid have been reported in crops such as ajwain, alfalfa, anthurium, artemisia, artichoke, barley, bean, black mustard, broad bean, chickpea, chicory, canola, coriander, corn, cotton, cucumber, cumin, fennel, fenugreek, goji, longan, milk thistle, millet, onion, pea, pepper, pistachio, radish, rice, rosemary, rye, safflower, saffron, savory, sorghum, soybean, spinach, strawberry, sugar beet, tomato, wheat, etc. Humic acid can improve and stimulate plant growth and yield, suppress diseases and promote more resistance to stresses. Fulvic acid can increase root system and promote seed germination, growth rate and final yield. The present manuscript highlights the most important impacts of salicylic acid, humic acid, and fulvic acid ,emphasizing their roles in modern sustainable crop production.
... Salicylic acid is an autogenous hormone which participates in multiple activities of plants such as seed and fruit yield and quality, seedling vigour, lipid peroxidation, nitrogen metabolism as well as in the defence system of plant for efficient quenching of ROS via antioxidant enzymes (Singh et al., 2016;Nazari et al., 2020). Salicylic acid enhances the ability of plants to tolerate different abiotic stresses by alleviating the development and growth of the plant. ...
... Priming memiliki peran penting dalam meningkatkan perkecambahan biji dan munculnya bibit di tanaman yang berbeda. Priming juga dilaporkan dapat meningkatkan perkecambahan dan munculnya bibit pada kondisi salinitas (Nazari et al., 2020) Seed coating atau pelapisan benih merupakan salah satu perlakuan untuk meningkatkan mutu benih. Perlakuan ini melapisi benih dengan lapisan tipis tanpa mengubah bentuk benih dengan tujuan untuk memperbaiki penampilan benih, meningkatkan daya simpan, mengurangi resiko penyakit dari micro-environment benih, dan dapat digunakan sebagai pembawa zat aditif, seperti antioksidan, anti mikroba, zat pengatur tumbuh ataupun pembawa mikroba bermanfaat (Ilyas et al., 2015;Utami et al., 2020). ...
... Drought causes an overabundance of ROS, which speeds up membrane lipid peroxidation and hence raises membrane permeability [14,18,19]. In this research, DS distinctly boosted EL % in cucumber leaves, which was in line with the findings of Nawaz and Wang [61] and Nazar et al. [62]. Such mutilation can be caused by oxidation and crosslinkage of protein thiols, and inhibition of key membrane proteins such as H + -ATPase [63]. ...
In order to alleviate the shortage of irrigation water in dry regions, refining water use efficiency (WUE) is a key issue in sustainable productivity. Furthermore, glycinebetaine (GlyBet) is a vital osmoprotectant produced in crops for improving drought tolerance; however, little is known about its role in improving plant WUE under field conditions in non-accumulating plants such as cucumber. In order to elucidate the effectiveness of GlyBet concentrations (0, 2000, 4000, and 6000 mg/L) in mitigating the deleterious effects of drought (e.g., well-watered (1250 m³/fed), moderate drought (950 m³/fed), and severe drought (650 m³/fed)), field experiments were conducted at Elmia village, Dakahlia, Egypt in the 2020 and 2021 seasons on vegetative growth, some physiological attributes, as well as yield and quality. Drought considerably decreased vegetative growth, yield and its components, leaf relative water content, and photosynthetic pigment concentrations compared with well-watered plants while increasing electrolyte leakage. The most harmful causes were severe drought. However, exogenous spraying with GlyBet substantially boosted the mentioned attributes, but reduced electrolyte leakage within well-watering. Commonly 6000 mg/L contributed to the maximum growth and productivity, preserving cucumber plant water status above other concentrations or untreated plants. Under extreme drought, the application of 6000 mg/L GlyBet had a beneficial effect on moderating the damage of water deficit on cucumber plant growth and productivity. Overall, using GlyBet as a cost-effective and eco-friendly biostimulant six times (10, 20, 30, 40, 50, and 60 days from sowing) has the potential to mitigate drought damage while also increasing yield; however, more research is needed to determine the optimal rate and timing of application.
... Pesquisas recentes indicam também efeitos do condicionamento de sementes com AS na melhoria do vigor. Nazari et al. (2020) O condicionamento fisiológico das sementes foi feito com os períodos de 28 e 70 h de embebição, para os cultivares All Big e Ikeda, respectivamente. Para determinar tais tempos, realizaram-se previamente curvas de embebição, adotando-se o tempo anterior à protrusão da raiz primária como o período ideal para o procedimento. ...
O condicionamento de sementes pode ser interessante para hortaliças. Objetivou-se no presente trabalho avaliar o efeito de diferentes doses de ácido salicílico no condicionamento fisiológico de sementes de diferentes cultivares de pimentão. Utilizaram-se sementes dos cultivares All Big e Ikeda, e as doses de ácido salicílico de: 0, 0,1, 0,2 e 0,4 (mM). Após o condicionamento, as sementes foram avaliadas quanto a: porcentagem e velocidade de germinação; germinação em estresse salino; crescimento de plântulas em condições normais e em estresse salino; envelhecimento acelerado. Verificou-se que o condicionamento fisiológico de sementes de pimentão tem efeitos diferenciais para os cultivares All Big e Ikeda. Para o cultivar All Big, o condicionamento fisiológico com 0,35 mM de ácido salicílico é eficiente para promover melhoria no potencial de germinação. O condicionamento fisiológico de sementes de pimentão com ácido salicílico não promove melhorias na velocidade de germinação e no comprimento de plântulas, para ambos os cultivares analisados, em condições normais, e para todas as variáveis testadas em meio salino. O condicionamento fisiológico de sementes de pimentão com 0,4 mM de ácido salicílico promove maior germinação de sementes após o envelhecimento acelerado para o cultivar Ikeda, contudo sem efeitos positivos no cultivar All Big.
... Seedling vigor has been difficult to define as it encompasses seed germination, emergence, and early growth under environmental influences (Finch-Savage & Bassel, 2016;Nazari et al., 2020). Reports of fungicide seed treatment impact on improving vigor across multiple field locations are limited. ...
Phytophthora root and stem rot is a devastating disease of soybean [Glycine max (L.) Merr.] that occurs annually in North America. Plant death and severe yield loss can transpire when conditions are favorable for pathogen development. The first objective was to determine the efficacy of oxathiapiprolin as a soybean seed treatment using laboratory inoculum layer assays with different races of Phytophthora sojae. The second objective was to evaluate oxathiapiprolin seed treatments in wide area agronomic field testing using unmanned aerial vehicle (UAV) image‐to‐data analysis to quantify emergence, vigor, and greenness traits. The final objective was to examine the yield potential of seed treatments with oxathiapiprolin. Using inoculum layer efficacy testing in a growth chamber with P. sojae races 4, 7, or 31, seed treated with oxathiapiprolin had significantly higher visual root growth scores compared to non‐treated seed. Across 115 field locations from 2018 to 2020, UAV remote sensing image analysis at the V2 growth stage indicated oxathiapiprolin in combination with other fungicides had significantly better emergence, more vigor, and more intense greenness compared to non‐treated controls. Entries treated with oxathiapiprolin in combination with other fungicides had an average +161 kg ha–1 yield difference compared to non‐treated entries from 2018 to 2020. Oxathiapiprolin as a seed treatment is an effective management tool for soybean producers, providing efficacy against P. sojae, and improving emergence, vigor, greenness, and final yield.
... The mechanism through which priming treatments improve seed viability is related to the repair of cellular and mitochondrial components [11], synthesis of nucleic acids and proteins, and recovery of antioxidants [12]. Previous studies indicated that priming with exogenous substances, e.g., ascorbic acid (AsA), glutathione (GSH), and salicylic acid (SA), significantly accelerated the germination of aged seeds in many species, including Siberian wildrye (Elymus sibiricus L.) [11], oat [13], and soybean (Glycine max (L.) Merr.) [14]. Although the involved structural and physiological changes have been explored [15,16], the proteomic differences and molecular mechanisms underlying the priming effects that promote germination of aged seeds are still relatively limited. ...
Melatonin priming is an effective strategy to improve the germination of aged oat (Avena sativa L.) seeds, but the mechanism involved in its time-course responses has remained largely unknown. In the present study, the phenotypic differences, ultrastructural changes, physiological characteristics, and proteomic profiles were examined in aged and melatonin-primed seed (with 10 μM melatonin treatment for 12, 24, and 36 h). Thus, 36 h priming (T36) had a better remediation effect on aged seeds, reflecting in the improved germinability and seedlings, relatively intact cell ultrastructures, and enhanced antioxidant capacity. Proteomic analysis revealed 201 differentially abundant proteins between aged and T36 seeds, of which 96 were up-accumulated. In melatonin-primed seeds, the restoration of membrane integrity by improved antioxidant capacity, which was affected by the stimulation of jasmonic acid synthesis via up-accumulation of 12-oxo-phytodienoic acid reductase, might be a candidate mechanism. Moreover, the relatively intact ultrastructures enabled amino acid metabolism and phenylpropanoid biosynthesis, which were closely associated with energy generation through intermediates of pyruvate, phosphoenolpyruvate, fumarate, and α-ketoglutarate, thus providing energy, active amino acids, and secondary metabolites necessary for germination improvement of aged seeds. These findings clarify the time-course related pathways associated with melatonin priming on promoting the germination of aged oat seeds.
... In this regard, destroyed FA structure https://doi.org/10.1016/j.indcrop.2020.112605 , accelerated lipid peroxidation (Bailly et al., 1996;Nazari et al., 2020;Tatić et al., 2012), and increased electrolyte leakage (Gidrol et al., 1989;Mohammadi et al., 2012) are well-known consequences associated with natural or artificial aging processes in oilseed crops. ...
Accelerated oil oxidation and degraded fatty acids (FA) composition are considered as well-known consequences in oilseed crops resulting from the imposed aging conditions. Hence, evaluating the effective techniques and understanding the biological mechanisms associated to mitigating seed deterioration process in medicinal pumpkin (Cucurbita pepo subsp. Pepo. Convar. Pepo var. styriaca Greb) may be necessary. In the current study, different durations of artificial accelerated aging (0, 48, 72, and 96 h) and priming solutions (water priming as control and γ-aminobutyric acid (GABA) priming at 1, 2, and 3 mmol L −1) were tested. From the results, a significant decrease in oil percentage and seedling dry weight was observed with increasing seed aging duration, whereas malondialdehyde content and electrolyte leakage significantly increased. Moreover, with increasing seed deterioration severity, percentage of saturated FA (SFA) significantly increased, while mono-and poly-unsaturated FA (MUFA and PUFA) decreased. In contrast, GABA priming alleviated the deleterious effects of seed deterioration on seedling growth and FA composition. For instance, after 96-h aging period, GABA priming at 3 mmol L −1 decreased SFA/MUFA and SFA/PUFA by 14.2 and 13.3%, respectively, compared with control. Overall, the results obtained here may confirm the crucial role of GABA priming to improve the successful establishment of seedlings raised from medicinal pumpkin seeds.
... The accelerated aging mechanism, especially associated with an increase in electrical conductivity (EC), can be a sign of gradual seed deterioration (Nazari et al. 2020). EC is an appropriate test for predicting soybean seed vigor, which is based on the leakage of ions and metabolites from the cell membrane during the process of seed soaking (Vieira et al. 2004). ...
Seed aging leads to reduced germination and vigor, especially in long-term storage, which can significantly reduce crop yields. Hence, identifying genetic mechanisms and providing physiological approaches to alleviate the deterioration process are needed. The current study was conducted in a series of laboratory experiments with soybean (Glycine max (L.) Merr.) in 2015. Accelerated aging durations (0 d, 6 d, and 10 d), priming solutions [dry seed, water, and 50 µM aminocyclopropane-1-carboxylic acid (ACC)] and priming periods (6 h and 12 h) were considered experimental factors. Total RNA was extracted from whole dry and imbibed seeds using hexadecyltrimethylammonium method. Genes and associated accessions studied were: LIG4 (XM_003546387.3), CTR1 (BW653506.1), GAI1 (BW656807.1), NCED1 (AK244131.1), and NCED5 (AK245513.1). With increasing severity of seed deterioration, the expression of LIG4, CTR1, GAI1, and NCED1 significantly increased, whereas a decreasing trend was observed for NCED5 expression. ACC had an inhibitory effect on germination index in aged soybean seed, which was associated with expression level of LIG4. Priming with ACC considerably reduced the inhibitory effect of CTR1, GAI1, and NCED1 in 6-day aged seeds, resulting in a positive effect on germination. It seems that positive or negative effects of ethylene priming on soybean germination depend on severity of seed deterioration.
Seed deterioration occurs gradually during long-term seed storage. Viability, vigour, and genetic integrity of African eggplant seeds were assessed under natural ageing during genebank storage. The percentage of tail DNA before and after seed imbibition was used to account for genotoxicity and DNA repair during cold dry storage at 10 °C using the comet assay. After 2, 5, and 12 years of storage in the genebank, a reduction of seed viability was observed in all studied African eggplant genotypes. However, seed viability was more significantly reduced in seed lots that had been stored for a longer period in the genebank (p < 0.05). Overall, higher viability loss was recorded in seeds regenerated 12 years before (p < 0.05). The molecular analysis by comet assay showed significant DNA damage during natural aging under genebank conditions, accompanied by important loss of viability and germination energy in older seeds translated into low DNA repair after seed imbibition. The seed lots which had better initial quality were able to maintain higher viability during genebank storage. The findings inform on the storage behaviour of African eggplant genotypes and are relevant for the proper handling of seed lots in genebanks. They are also relevant for future studies on seed longevity prediction in African eggplant.
Drought, a global challenge, severely restricts growth and development of agronomic and horticultural crops. Cucumber (Cucumis sativus L.) is a water-intensive crop and water scarcity at critical growth stages significantly reduces its fruit yield and quality. Several plant growth regulators are applied as a mitigation strategy, and salicylic acid (SA) is one such option. However, the potential role of SA under different application methods in alleviating drought stress in cucumber has not been thoroughly investigated. The objective of this study was to evaluate the effects of SA applied as a seed priming material or foliar spray on cucumber plants under drought stress. Laboratory and polyhouse experiments were conducted. Salicylic acid was applied in five doses (0 [control], 0.25, 0.50, 0.75, and 1.00 mM) either as a seed priming material (in laboratory study and experiment 1 in the polyhouse) or as a foliar spray (experiment 2 in the polyhouse) under four soil moisture regimes (40%, 60%, 80%, and 100% field capacity [FC]). Throughout the crop growth period, a portable soil moisture meter was used to regularly monitor soil moisture regimes for maintaining the appropriate FC levels. The effect of decreasing soil moisture was evident on all evaluated parameters and caused up to 84% reduction in fruit yield at 40% FC compared with that at 100% FC in both polyhouse experiments. A consistent trend of better results with 0.75 mM dose of SA regardless of application methods or crop growth stages was observed, which resulted in a significant increase in all germination parameters, growth, and fruit yield, as well as physiological traits. The same dose (0.75 mM) caused an increase of 19–69% and 31–69% in shoot dry matter in comparison to the control plants across soil moisture regimes applied as a seed priming material and foliar spray, respectively. More than threefold increase in fruit yield and water productivity was observed for this dose at 60% FC in both polyhouse experiments in comparison to the control plants. Compared with the control plants, the same dose also caused a significant increase in leaf relative water content and membrane stability index irrespective of application methods or soil moisture regimes. The highest dose of 1.00 mM largely remained ineffective and the same was also generally true for the other doses applied in the present studies. Application of SA at 0.75 mM is recommended either as a seed priming material or foliar spray to grow cucumber in drought-prone areas.
A systematic approach was employed with the objective of compiling updated
and more promising information on the quality of soybean seeds, traits, treatments and analysis techniques. Among the 6,899 academic materials retrieved between 2017 and 2022, 57 of them were included in the study, separated into three groups: Group 1 - Theoretical materials addressing traits related to seed vigor, which can be used in biotechnological strategies and improvement of different species; Group 2 - Practical materials that apply
techniques of treatment of soybean seeds; and Group 3 - Practical materials that apply techniques to evaluate vigor in soybean seeds. From the approach used, it was possible to observe that several genes, proteins and QTLs are associated with seed vigor. Seed treatment techniques focus on the use of biological and physical products, but there is a lack of studies validating these benefits in the field. Among the methods for evaluating the vigor of soybean seeds, the techniques of image analysis (visible light, LIBS, NIR, FTIR, FTNIR, HSI-NIR, FHSI, Hyperspectral, Fluorescence spectral) and the use of software (Vigor-S®, SVIS®, SAPL®, IJCropSeed, Ilastik, VideometerLab®, MATLAB, ENVI®) stand out.
Cantaloupe is a nutritive and popular commercial fruit crop. Soil moisture deficit could seriously jeopardize the yield and quality of cantaloupe. Salicylic acid (SA) has a proven role in sustainably mitigating environmental stresses in many plants applied through various methods. A factorial experiment consisting of six SA seed priming doses (non-primed control, 100, 200, 300, 400, and 500 ppm) and three soil moisture regimes (50%, 75%, and 100% field capacity [FC]) was conducted to evaluate the performance of cantaloupe in terms of growth, physiological traits, fruit yield, and quality parameters. The results revealed that severe moisture-deficit condition of 50% FC drastically reduced fruit yield (64%), water productivity (48%), total soluble solids (22%), and membrane stability index (43%), while electrolyte leakage was increased by 260% at the same soil moisture regime compared with 100% FC without any SA application. Plants grown from SA primed seeds exhibited significantly better performance in terms of seed germination traits, growth, physiological, and fruit yield parameters than non-primed plants across soil moister regimes. The performance of cantaloupe in terms of germination rate, root and shoot dry matter, fruit yield, water productivity, total soluble solids content, and membrane stability index was better at 300 ppm SA priming dose, which was statistically similar with 400 and 500 ppm SA doses in most cases. A consistent trend of better performance at 300 ppm SA dose, especially at severe soil moisture-deficit of 50% FC, was observed (48%, 59%, 54%, and 153% higher fruit yield, water productivity, membrane stability index, and net photosynthetic rate, respectively, compared with the non-primed control at the same soil moisture regime). There was almost no effect of increasing SA priming dose above 300 ppm; therefore, this could be regarded as an optimum dose for maximizing productivity and economic returns when cantaloupe is grown under soil moisture-deficit conditions.
Loss of quality, viability and irreversible seed vigor over time due to seed aging is one of the main causes of reduction of quality and quantity of agricultural production. A wide range of secondary metabolites such as vitamins, growth regulators and antioxidant compounds were used to reduce the harmful effects of a variety of environmental stresses such as seed aging. These can be applied as seed pretreatment or foliar spraying of plants. To investigate the effect of seaweed extract (Ascophyllum nodosum) and ellagic acid on quality improvement of soybean, an experiment was designed and implemented in the field during 2019 and 2020. A factorial experiment was conducted based on a randomized complete block design (RCBD) with three replications. Two sets of seeds (un-aged and aged seeds), seed pretreatments and foliar spray treatments with ellagic acid and the seaweed extract to plants produced from aged seeds were conducted at three levels (control (zero), 50 mg/L of ellagic acid and 0.3% seaweed extract). The foliar spraying is done to improve the vigor of plants produced from aged seeds. Seed aging reduced the final emergence percentage under the field conditions. Seed pretreatments with the seaweed extract and ellagic acid increased the emergence. The amount of malondialdehyde, the activity of lipoxygenase, flavonoids and anthocyanins content also increased in the leaves of plants grown from the aged seeds in the field conditions. Seed aging reduced glutathione content, protein yield and seed yield. However, seed pretreatments with ellagic acid and the seaweed extract increased protein yield by 27.2% and 53.4%, respectively. Seed yield in plants grown from seeds treated with ellagic acid increased by 28.2%. Seed yield increased by 53.6% with application of seaweed extract as seed pretreatment. Foliar spray of ellagic acid and the seaweed extract to plants increased protein yield by 20.6% and 21.5%, respectively. Thus seed pretreatments and foliar spray of ellagic acid and the seaweed extract countered the effects of accelerated aging of soybean seed.
Nitric oxide (NO) can act in biochemical pathways of the germination process; however, there is little information about how it acts on the performance of pea seeds. The aim of this study was to evaluate the physiological and biochemical effects of NO on pea seed germination and vigor. Pea seeds cv. Itapuã 600 obtained from three seed lots with different levels of physiological quality were sown in a substrate moistened with water (control) or sodium nitroprusside (SNP) solution, a NO donor (50 μM), to assess germination, vigor, activity of antioxidant enzymes, reactive oxygen species, lipid peroxidation, and amylase activity. NO application does not alter pea seed germination, but it increases vigor. It is more effective in seeds with lower physiological potential. In addition, NO leads to reduction in oxidative stress, favors the translocation of reserves to the embryo, and has potential for use in the treatment of pea seeds to increase seed vigor.
The aim was identification of patterns of changes in the physical and chemical state of biopolymers in durum and soft wheat seeds after the treatment of impulse pressure (IP) and during the storage of seeds. It was found that durum wheat seeds accumulated microcracks over the structure of the glassy endosperm after the IP treatment, while soft wheat seeds reacted to IP treatment by “collapsing” air gaps in the loose endosperm, as well as by vitrification of amorphous areas that were in a highly elastic state and the transition of crystalline areas to vitreous ones. The vitreous content of durum seeds decreased, while that of soft seeds increased linearly after the treatment by IP and storage. Treatment of soft wheat seeds with IP and storage increased their germination, growth and quality of seedlings due to vitrification of the seed endosperm. The decrease in the vitreousness of durum wheat grain after the treatment with IP and storage led to deterioration in the quality of grain and sprouts during storage. So the glassy state in seeds is suggested to serve as a stabilizer. The rapid progress of deterioration may represent a weakening of the glassy state.
Oil content and fatty acid composition are important traits for assessing and modeling germination in oilseeds. On the other hand, seed germination and seedling growth are affected by the weight of mobilized seed reserves and the conversion efficiency of mobilized seed reserve to seedlings tissues. In order to examine seeds physiological aspects and heterotrophic seedlings growth of 12 winter canola cultivars (Fornax, Karaj 1, Karaj 2, Karaj 3, L73, L201, Licord, Modena, Okapi, Opera, SLM046, and Zarfam) as related to seed reserves, series of laboratory experiments were conducted in Ferdowsi University of Mashhad, Mashhad, Iran. At the first and the second stages (before and after the performing accelerated aging test), significant differences were found among cultivars in terms of oil percentage. From the results, N, P and crude protein contents in seeds were decreased due to accelerated aging. Moreover, a positive correlation was found between electrical conductivity (EC) of seed soaking solution and mean germination time (MGT). By contrast, the correlation between weight of mobilized seed reserve (WMSR) and seed reserve utilization efficiency (SRUE) with MGT were significantly negative. Accelerated aging in canola seeds increased saturated fatty acids percentage and reduced unsaturated fatty acids percentage. There was a positive and significant relationship between oleic acid and SRUE. By contrast, the relationship between linolenic or linoleic acid and SRUE was found to be negative. According to the results, it seems that seed vigor and heterotrophic seedlings growth in canola highly depends on fatty acids composition.
The present study was designed to highlight the effects of cold plasma (10 kV) treatment and priming with 2 mM salicylic acid (SA) and their combination (10 kV of plasma + 2 mM SA) on the physiological parameters and metabolism of two cultivars of Oryza sativa, i.e., Zhu Liang You 06 (ZY) and Qian You No. 1 (QY), under salinity stress (150 mM NaCl) and normal growth condition (0 mM NaCl). Seed germination and seedling growth were enhanced by SA priming and cold plasma treatment either alone or in combination under salinity stress. Photosynthetic pigments, photosynthetic gas exchange, and chlorophyll fluorescence were improved by cold plasma treatment and SA priming under salinity stress as compared to the untreated seeds. The activities of antioxidant enzymes were significantly improved by the combination of SA priming and cold plasma treatment in both cultivars under salinity stress. There were rapid changes in the cellular content of sodium (Na+) and calcium (Ca+), where the plants grown under saline conditions accumulate more Na+ and less Ca+ contents resulting in ionic imbalances. Interestingly, cold plasma and SA treatments diminished this action by reducing Na+ accumulation and increasing K+ and Ca+ contents in the plant cell under salinity stress. The activities of enzymes involved in secondary metabolism assimilation were up-regulated with cold plasma and SA priming either alone or combination under salinity stress. An increase in reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) content was also observed under salinity stress condition. On contrast, seed treated with SA and plasma alone or combined resulted in a significant decrease in ROS and MDA contents under salinity stress. Our results indicated that SA priming and cold plasma treatment either alone or combined improved plant uptake of nutrients in both cultivars under stress conditions. The ultrastructural changes were observed to be more prominent in ZY than QY cultivar. Plants without SA priming or cold plasma treatments have a big vacuole due to the movement of ions into the vacuole directly from the apoplast into the vacuole through membrane vesiculation leading to membrane destabilization. However, SA priming and cold plasma treatment alone or combined helped the plants to recover their cell turgidity under salinity stress.
The effect of 0.5–1.5 mM salicylic acid (SA) on modulating reactive oxygen species metabolism and ascorbate–glutathione cycle in NaCl-stressed Nitraria tangutorum seedlings was investigated. The individual plant fresh weight (PFW) and plant dry weight (PDW) significantly increased under 100 mM NaCl while remained unchanged or decreased under 200–400 mM NaCl compared to the control. Superoxide anion (O2·−), hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS), reduced ascorbate (AsA), dehydroascorbate (DHA), reduced glutathione (GSH) and oxidized glutathione (GSSG) increased whereas the ratios of AsA/DHA and GSH/GSSG decreased under varied NaCl treatments. Ascorbate peroxidase (APX) and glutathione reductase (GR) activities were enhanced while dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) activities remained unvaried under 100–400 mM NaCl stresses. In addition, exogenous SA further increased PFW, PDW and root/shoot ratio. SA effectively diminished O2·− accumulation. H2O2 and TBARS decreased under 0.5 and 1.0 mM SA treatments compared to those without SA. 0.5 mM of SA increased while 1.0 and 1.5 mM SA decreased APX activities. DHAR activities were elevated by 0.5 and 1.0 mM SA but not by 1.5 mM SA. MDHAR and GR activities kept constant or significantly increased at varying SA concentrations. Under SA treatments, AsA and GSH contents further increased, DHA and GSSG levels remained unaltered, while the decreases in AsA/DHA and GSH/GSSG ratios were inhibited. The above results demonstrated that the enhanced tolerance of N. tangutorum seedlings conferred by SA could be attributed mainly to the elevated GR and DHAR activities as well as the increased AsA/DHA and GSH/GSSG ratios.
Reduction of seedling growth is a consequence of seed deterioration. An experiment was conducted to evaluate the effects of duration of seed aging on soybean seed germination characteristics. Experiment conducted as completely randomized design with 4 replications. The seeds of DPX line of soybean with 15-16% moisture were incubated for 3, 7, 10, 14, 17 day at 40C in sealed containers for ageing treatment and non aged seeds were considered as control. Results showed that rapid aging treatment has a significant effect on studied parameters. Germination percent (GP), means of daily germination (MDG), means time to germination (MTG), coefficient of velocity of germination (CVG) and germination index (GI) decrease significantly. Also, germination uniformity (GU) was affected by deterioration time. Abnormal seedling (ABS) percentage increased. Results shows that rapid aging experiment could be a useful test for determine soybean seed quality.
We investigated the storage behaviour of karanj (Pongamia pinnata L. Pierre), a very popular tree valued for medicinal and biodiesel use, seeds at ambient conditions (27–30 °C and RH 45%). Fresh karanj seeds, showing 100% germination were shed with water content of 0.22 gH2O g− 1 DM. The karanj seeds exhibited intermediate storage behaviour as the percent germination dropped from 100 to 80% when the seeds desiccated below critical water content i.e. 0.11 gH2O g− 1 DM. The loss of germination index (GI) and viability, and increase in solute leakage preceded the loss of germinability. Dehydration mediated decline in seed viability and vigour was negatively associated with accumulation of reactive oxygen species (ROS, like superoxide radical and H2O2). In dehydrating seeds, excess amounts of ROS mediated cellular damage by oxidizing biomolecules like lipids and proteins. The activities of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were higher in the 100% viable seeds, and reduced with dehydration induced viability and vigour loss. The expression of specific isoenzymes of SOD (band 1) and CAT (band 2) detected only in seeds exhibiting higher germination, may be considered as markers for seed quality.
We studied the influence of seed priming with beta-amino butyric acid (BABA) on the growth, physiological and biochemical parameters of seedlings with varied abiotic stress tolerance, which were raised and grown under unstressed and stressed (NaCl/PEG-6000) conditions. Under stressed conditions, the growth of rice seedlings was less when compared to control plants. After BABA priming, the seedling growth increased both under unstressed and stressed conditions as compared to the respective controls. BABA priming of rice seeds caused increase in the photosynthetic pigment content of the leaves, modified the chlorophyll a fluorescence related parameters and also enhanced the photosystem activities of seedlings when compared to their respective non-primed controls. BABA priming also caused increased mitochondrial activities of the rice seedlings. Moreover, BABA priming significantly reduced malondialdehyde content in the seedlings and also resulted in accumulation of proline especially in the NaCl tolerant variety Vyttila 6. BABA seed priming also enhanced the activity of nitrate reductase enzyme and activities of antioxidant enzymes like guaiacol peroxidase and superoxide dismutase. The presence of BABA was detected by high performance thin layer chromatography analysis in the rice seeds whereas in the seedlings it was not detected. Thus, it can be inferred that the seed priming effect of BABA mainly occurred within the seeds, which was further carried to the seedlings. It is concluded that BABA priming of seeds improved the drought and salinity stress tolerance of all the three rice varieties and it was significantly evident in the drought tolerant variety Vaisakh and NaCl tolerant variety Vyttila 6, when compared to the stress sensitive variety Neeraja.
Seed germination is the critical stage for species survival. Salinity affects germination and seedling growth and yield of several crop species, such as broad bean. That is why this study was carried to evaluate the effects of NaCl on seed germination and influence of salicylic acid on seedin order to improving salt tolerant on broad bean. Vicia faba L. is an important pulse crop in the Mediterranean region. In many cases broad bean is grown on saline soils where growth and yield are limited by salinity.The Results showed that Irrigation with saline water significantly reduced all Seed germination parameters in comparison to the respective control. Alleviation of growth arrest was observed with exogenous applications of salicylic acid (SA) under salt stress conditions. Overall, the positive effect of SA towards resistance to the salinity of Vicia faba L. will provide some practical basis for Vicia faba L cultivation.
Salicylic acid (SA) is a well-known signalling molecule playing a role in local and systemic acquired resistance against pathogens as well as in acclimation to certain abiotic stressors. As a stress-related signalling compound, it may directly or indirectly affect various physiological processes, including photosynthesis. The effects of exogenously applied SA on plant physiological processes under optimal environmental conditions are controversial. Several studies suggest that SA may have a positive effect on germination or plant growth in various plant species. However, SA may also act as a stress factor, having a negative influence on various physiological processes. Its mode of action depends greatly on several factors, such as the plant species, the environmental conditions (light, temperature, etc.) and the concentration. Exogenous SA may also alleviate the damaging effects of various stress factors, and this protection may also be manifested as higher photosynthetic capacity. Unfavourable environmental conditions have also been shown to increase the endogenous SA level in plants. Recent results strongly suggest that controlled SA levels are important in plants for optimal photosynthetic performance and for acclimation to changing environmental stimuli. The present review discusses the effects of exogenous and endogenous SA on the photosynthetic processes under optimal and stress conditions.
In this study, the effect of 100 µM salicylic acid (SA) priming on Hedysarum coronarium (a cosmopolitan species) and Hedysarum carnosum (a species endemic to Tunisian salt flats) subjected to 200 mM of NaCl at germination and seedling growth stages was analyzed. SA priming had a beneficial effect on germination, which was related to imbibition rather than reserve mobilisation, since the dry biomass of cotyledons was unchanged by salt stress and SA priming. The results showed that SA priming at the seedling growth stage alleviated salt-induced oxidative stress by reducing malondialdehyde (MDA) and H 2 O 2 content. In addition, the two species demonstrated differential H 2 O 2 detoxification with the stimulation of catalase (CAT) activity in both species, but guaiacol peroxidase (GPX) stimulation was found to only occur in H. coronarium. Surprisingly, H. coronarium seedlings proved to be more tolerant to NaCl stress than H. carnosum seedlings. SA priming reinforced the salt tolerance of H. coronarium at both germination and seedling growth stages.
The effects of soaking common bean (Phaseolus vulgaris L.) seeds in 5.0 μM 24-epibrassinolide (EBL) or in 1.0 mM salicylic acid (SA) on seed germination and seedling growth, drought tolerance, osmoprotectant molecule concentrations, and anti-oxidant systems when grown under 100 mM NaCl stress were investigated. EBL or SA alleviated the adverse effects of NaCl-stress to varying degrees. Despite the preference for EBL, soaking seeds in either compound increased the seed germination percentage, seedling growth, the cell membrane stability index, the relative water content, osmoprotectant concentrations, and the activity of the anti-oxidant system, while it reduced lipid peroxidation and electrolyte leakage compared to control seeds soaked in distilled water. These findings are important as the potential of EBL or SA to alleviate the harmful effects of NaCl stress offers an opportunity to increase the resistance of common bean plants to growth under saline conditions.
The aim of this study was to evaluate growth, lipid peroxidation, and activity of antioxidative enzymes in sorghum seedlings grown under salt stress from artificially aged and primed seeds. The experimental design was completely randomized, with four replications per treatment, in a 2×2×2 factorial arrangement that consisted of eight treatments: two seed vigor levels (aged or not), two seed types (primed or not), and two salinity levels (0 and 100 mM NaCl). In low physiological quality (aged) seeds, the osmoconditioning mitigated the salinity negative effects (NaCl at 100 mM) on seedling growth. The results suggest that osmoconditioning induced an increase in catalase (CAT) and guaiacol peroxidase (POX) activities and these enzymes protected the seedlings against oxidative damage caused by seed accelerated aging and salinity in nutrient solutions. Finally, the observed behavior for superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities suggest that changes in these enzymes in both shoot and roots could do not be induced by studied treatments, because the changes in these organs are unrelated to each other.
The emergence of 22 commercial seed lots (12 in 2005 and 10 in 2006) of melon (Cucumis melo L.) with laboratory germinations greater than 90% were compared in low temperature (LTE), mechanical stress (MSE), high temperature (HTE), and salt stress (SSE) sowing conditions. The seedling emergence percentage ranged between 18% and 79% for LTE, 15% and 90% for MSE, 27% and 84% for HTE, and 49% and 92% for SSE in 2005; and 43% and 85% for LTE, 30% and 82% for MSE, 56% and 91% for HTE, and 49% and 89% for SSE in 2006. The germination of the lots was determined after controlled deterioration (CD) with 20% or 24% moisture content (MC) and accelerated aging (AA) at 40 and 45 oC in 2005; or at 45 and 47 oC in 2006 for 48, 72, 96, 120, and 144 h. Germination after various combinations of CD and AA was positively and significantly (P < 0.05) correlated with LTE, MSE, HTE, and SSE. Correlation values (0.17 to 0.78) of the initial laboratory germination were much lower than those of both aging tests. The optimum CD conditions of 48 h and 20%MC at 45 8C and AA conditions of 120 h at 45 to 47 oC are suggested as vigor tests to estimate relative seedling emergence of melon seeds.
The objectives of the study were to evaluate the role of osmopriming on improvement of germination and seedling characteristics of four amaranth genotypes under simulated salt and drought stress. Germination was delayed by both treatments. At lower osmotic potentials, germination percentage,
germination rate, root and shoot length were higher in NaCl than PEG at the same water potentials. Seeds were able to germinate in all concentrations of NaCl but no seed germination was observed at −1.2 MPa of PEG treatments. It was concluded that inhibition of germination resulted from
osmotic effect rather than salt toxicity. Osmopriming increased germination and seedling growth under salt stress. For drought conditions, osmopriming did not have any positive effects on germination characteristics at lower osmotic potentials (−0.9 and −1.2 MPa).
The effects of seed hardening treatments using different salt solutions on the germination, emergence and seedling vigor in coarse and fine rice were investigated in a laboratory trial. Seeds were hardened both using tap water (referred to as hardening) and with CaCl2, KNO3, KCl, NaCl solution (osmohardening) in such way that osmotic potential of all the solutions was - 1.25 MPa. In both coarse and fine rice, osmohardening with CaCl2 performed the best compared with all other treatments as indicated by lower values of time to start germination, MGT, T50 and MET and higher values of final germination and emergence, speed and energy of germination, root and shoot length and seedling fresh and dry weight. Simple hardening and osmo-hardening with KCl were next best treatments.
Previous work on maize and other crops has indicated that measurements of mean germination time (MGT), the reciprocal of which is the rate of germination, is a possible alternative assessment of vigour to the cold test. Emergence comparisons were made of 11 commercial seed lots from different hybrids from four different production years, over two experimental runs in unsterilised soil in growth cabinets at 13°C. The lots, all with high warm (25°C) germinations, but differing in the cold test, showed significant differences in final emergence in both runs. Emergence was significantly related to mean emergence time (MET) in soil, slower emergence being associated with lower emergence. Smaller and more variable seedlings were significantly associated with slower emergence. These differences in soil corresponded with differences in germination in moist towels. At 13°C the mean just germination rate (MJGT), calculated from the time of the first appearance of the radicle, and the mean germination rate (MGT), calculated from the 2mm radicle germination stage, were significantly correlated with measurements in soil: positively with MET, negatively with seedling size and positively with variation in seeding length. In towels, MJGT at 20°C was closely related to MJGT and MGT at 13°C and for both temperatures mean root length was lower and more variable in the slower germinating lots. The earliness and synchronicity of the first signs of germination are proposed as a determining influence on performance in soil. The view that deterioration was the cause of higher MJGT, MGT, MET (i.e. slower rates) and differences in soil in final emergence, seedling size and variation is discussed. In conclusion, there is potential for comparative measurements of mean germination time as an indicator of field emergence in maize.
A wide range of seedling emergence in commercial seed lots of watermelon (10 lots), melon (10 lots) and cucumber (9 lots), all with standard germinations above 98%, was seen in low temperature emergence (LTE), high temperature (HTE) and an 8 cm deep sowing (MSE) in the field and in
salt stress conditions (SSE) in trays at 20°C. Final emergence was closely related to both the rate of emergence, measured as mean emergence time (MET; the reciprocal of the rate of emergence), and to the mean germination time (MGT; the reciprocal of the rate of germination) for physiological
germination (2 mm radicle) in the laboratory at 25°C. Slower germinating and emerging lots, so-called low vigour lots, had lower levels of emergence in all sowings. Single early counts of physiological germination identified low vigour lots for all three species and are suggested as a
quick routine test. The physiological age of the seed lots, determined using accelerated ageing (45°C in 100% relative humidity) and controlled deterioration (45°C and 20 or 24% moisture content), was significantly related to MGT which was higher (i.e. germination was slower) in physiologically
older seed. Previous work suggests that cucurbit seeds appear to retain germination capacity over several years although ageing is reflected in a slower rate of germination (high MGT). MGT can also be described as the length of the lag period from the start of imbibition to radicle protrusion.
We propose that this period is needed for the repair of the effects of ageing and is therefore longer in aged seeds.
Early spring sowing in maize requires seed capable of germinating and emerging promptly in cold and wet soils, and in this respect the availability of laboratory methods with high predictive value is relevant. This work was aimed at comparing the suitability of three vigour tests to
predict field performance, under unfavourable conditions, of maize (Zea mays L.) seed lots of high germination potential. Thirty lots, all with a standard germination (SG) higher than 92%, were submitted to a cold test in sand (CT), a soak test (ST) and accelerated ageing (AA), and
their performance in the field was assessed in early sowing at one site. A wide range of seed vigour was detected by the three tests, and in particular by the AA test, as well as a wide variation in field performance (final emergence, mean emergence time, mean emergence rate) as a consequence
of the rather low soil temperatures. The CT showed the highest correlations with field performance, and ST the lowest, presumably due to the good aeration of the seedbed; the vigour of seed lots, as detected by the AA test, was more strongly affected by seed age than that revealed by other
vigour tests or by field traits.
The effects of hormonal priming on physiological quality and antioxidant enzymes of aged seeds of tall wheatgrass were evaluated under control and drought (−0.5MPa) conditions. Rate of germination, vigour index and growth of root, shoot and seedling were declined by stress conditions.
According to the results, hormonal priming improved physiological quality of deteriorated seeds of tall wheatgrass under drought and control conditions. Germination percentage and rate of germination of primed seeds were higher than non-primed seeds under drought condition. 50ppm of auxin
increased germination of naturally aged seeds by 18% under drought condition. Likewise, cytokinin treatment resulted in the highest vigour index. Auxin decreased root length and increased number of seminal roots. For other hormones, seed priming by 100ppm of gibberellin, 50ppm of cytokinin,
and 50ppm of abscisic acid (ABA) improved seed performance under control and drought conditions. For antioxidant enzymes, both aging treatments (natural and accelerated) increased catalyse (CAT), glutathione reductase (GR) and peroxidase (POD) activities. Superoxide dismutase (SOD) activity
and isozyme profiles were different between natural and accelerated seed aging. According to the results of this study, four and two SOD isozymes were detected in naturally and accelerated aging seeds, respectively. Comparing antioxidant enzymes during germination, in advance activity of CAT
and POD were detected. According to the results, seed priming increased activity of antioxidant enzymes, however, hormonal priming was more effective. Variation in activity of antioxidant enzymes under various aging treatments could be a way of different molecular mechanisms of oxidative damage
and therefore repair mechanism of seed deterioration is not similar in naturally and accelerated aging methods.
A greenhouse experiment was conducted to study the effect of drought stress on seed germination and vigor of soybean in relation with soluble sugars. Three drought stress treatments, well-watered treatment (WW), gradual stress (GS) imposed prior to severe stress treatment, and sudden severe stress (SS), were imposed on soybean plants at beginning seed fill stage (R5) for 20–23 d. Drought stress, whether sudden or gradual, increased the percentage (by number) of small and medium seeds compared with the well-watered treatment. In general, the small and medium seeds had lower germination than the large seeds. Drought stress reduced the germination of medium seeds compared with those from well-watered plants, but did not change the standard germination of the large seeds. The vigor of the large seeds, as indicated by germination after accelerated aging (AA) (100% RH at 42°C for 72 h), was reduced by the SS treatment compared to GS and WW treatments. Although, the GS treatment gave an advantage in AA germination over the SS treatment, both of the drought stress treatments were detrimental to the formation of large seeds. Drought stress (GS and SS) reduced the concentration of sucrose in the full, rounded large seeds compared with WW treatment. In conclusion, the reduction in germination after accelerated aging in seeds from drought stressed plants was associated with the reduction in sucrose in full, rounded large seeds.
The objectives of the present work were to investigate whether loss of sunflower (Helianthus annuus L.) seed viability was affected by the embryo moisture content (MC) during seed pretreatment at 35°C, and was related to changes in energy metabolism and in the antioxidant defence system. Non-dormant seeds were equilibrated at MC of the embryonic axis ranging from 0.037 to 0.605 g H2O g−1 dry matter (DM) for 1 day at 15°C, and they were then placed at 35°C for various durations up to 14 days before the germination assays at 15°C. As expected, the higher the MC, the faster was seed deterioration. There existed a negative linear relationship between the time taken for germination to drop to 50% (P50) and the embryonic axis MC ranging from 0.108 and 0.438 g H2O g−1 DM. In dry seeds, adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate represented 6.3, 14.8 and 70.9% of the adenylate pool, respectively, and the energy charge (EC) was very low (0.14). ATP and ADP levels and EC increased sharply during the first day of equilibrium of seeds at a MC above 0.158 g H2O g−1 DM. Subsequent controlled deterioration at 35°C resulted in a decrease in the adenylate pool, and consequently in ATP level. The higher the energy metabolism during ageing, the lower was seed viability. Loss of seed viability was associated with an accumulation of H2O2, and then of malondialdehyde (MDA) suggesting that lipid peroxidation was not the only cause of seed deterioration. When there was a sublinear relationship between H2O2 content in the embryonic axis and seed viability, MDA accumulation only occurred when 50% of the seed population died within 7 days, i.e. when MC was higher than 0.248 g H2O g−1 DM. Ageing was associated with a decrease in the activity of superoxide dismutase, catalase and glutathione reductase, the main enzymes involved in cell detoxification. The involvement of seed MC, as key factor of ageing is discussed with regards to energy metabolism and the regulation of active oxygen species accumulation.
Active oxygen species (AOS) are involved in various aspects of seed physiology. Their generation, which occurs during seed desiccation, germination and ageing, may lead to oxidative stress and cellular damage, resulting in seed deterioration. However, cells are endowed with detoxifying enzymes and antioxidant compounds that scavenge AOS and participate in seed survival. The detoxifying mechanisms play a key role in acquisition of desiccation tolerance of developing seeds, completion of seed germination and seed storability. However, AOS must also be regarded as molecules intervening in cellular signalling. They are involved in growth processes occurring at early embryogenesis during seed development, and participate in the mechanisms underlying radicle protrusion during seed germination. AOS might also have a regulatory function in the changes in gene expression during seed development, dormancy and germination. Their interplay with other molecules, particularly with hormones such as abscisic acid, suggests that they should be considered as key components of an integrated signalling network involved in many aspects of seed physiology.
Reactive oxygen species (ROS) and lipid peroxidation products appear to correlate strongly with the desiccation induced loss of viability in recalcitrant sal seeds. The 100% germination in fresh sal seeds declined with dehydration under natural storage conditions (26 ± 1 °C, relative humidity 52 ± 2%). Seeds became non-viable within 8 days. Desiccation induced disturbances in the metabolic activity of seeds resulted in generation of enormous amounts of ROS that are responsible for cellular damage and viability loss. Oxidative stress in the dehydrating aging sal seeds was further aggravated by inducing lipid peroxidation as the amounts of free fatty acid, conjugated diene, lipid hydroperoxide and secondary free radicals; malondialdehyde and 4-hydroxy-2-nonenal, were also promoted. In addition, significant rise in lipid degrading enzymes; lipase (EC 3.1.1.3) and lipoxygenase (LOX, EC 1.13.11.12) were detected in dehydrating sal seeds. Our results indicated multiple pathways (ROS, lipid peroxidation & lipase and LOX) that operate in the dehydrating recalcitrant sal seeds finally contributing to loss of viability.
Drought is a major abiotic stress limiting the agricultural production of safflower (Carthamus tinctorius L.). To mitigate stress, the effects of salicylic acid and sodium nitroprusside on the growth of Carthamus tinctorius L. under normal and water deficit conditions were studied to understand the underlying stress tolerance mechanisms. Nitric oxide is an important signaling molecule in the regulation of diverse physiological processes specially stress tolerance. Salicylic acid is a growth regulator playing important roles in mitigating both biotic and abiotic stresses. The plants aged 23-days old were irrigated with different field capacity volumes of water (25% and 100%) with or without salicylic acid (0 and 250 μM) and sodium nitroprusside (0 and 25 μM). The plants were harvested and characterized by spectrophotometer and gel electrophoresis for certain physiological and biochemical features. The salicylic acid caused rapid activation of non-enzymatic defense system accompanied by increased production of osmolytes and such non-enzymatic scavengers as proline. The sodium nitroprusside application was more activated the enzymatic defense system, promoted the superoxide dismutase and catalase activities and gene expression of two subunits of Fe- and Cu-superoxide dismutase. Both of these adaptive mechanisms reduced free radicals as well as lipid peroxidation and improved the membrane stability and water deficit tolerance of the plants. Their combined applications brought the plant to nearly normal growth conditions. The simultaneous or separate application to plants under normal growth conditions are not suggested as they will act as stress and impair plant growth.
The present study identified inverse relationships between nickel (Ni) levels and growth, photosynthesis and physio-biochemical attributes, but increasing levels of Ni stress enhanced methylglyoxal, electrolyte leakage, hydrogen peroxide, and lipid peroxidation content. Exogenous application of salicylic acid (SA) (10 −5 M) ameliorated the ill-effects of Ni by restoring growth, photosynthesis and physio-biochemical attributes and increasing the activities of enzymes associated with antioxidant systems, especially the ascorbate-glutathione (AsA-GSH) cycle and glyoxalase system. In addition, SA application to Ni-stressed plants had an additive effect on the activities of the ascorbate and glutathione pools, and the AsA-GSH cycle enzymes (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase), superoxide dismutase, catalase, glutathione S-transferase, and osmolyte biosynthesis). This trend also follows in glyoxalase system viz. glyoxalase I and glyoxalase II enzymes. Nevertheless, exogenous SA supplementation restored mineral nutrient contents. Principal component analysis showed that growth, photosynthesis, and mineral nutrient parameters were positively correlated with each other and negatively correlated with antioxidant enzymes and oxidative stress biomarkers. Hence, SA is an alternative compound with potential application in the phytoremediation of Ni.
Among the different naturally occurring plant hormones Salicylic Acid (SA) is one of the important signal molecules. The current study was carried out to investigate whether foliar spray of SA could improve the different parameters and help to alleviate the saline stress in rice seedlings. Saline stress (100 mM NaCl) significantly reduced the photosynthetic and total protein content. Increased NaCl concentration exhibited a significant increase in antioxidant enzymes activity. Plants grown under high saline stress showed more accumulation of ROS with DAB staining and exhibited the fragmented nuclei by DAPI staining. Foliar spray of SA showed the improved photosynthetic and protein content, reduced antioxidant enzymes activity, lower accumulation of ROS and intact nuclei. Further, expression of Catalase-1 (CAT-1), Superoxide dismutase (SOD) and Glutathione Peroxidase (GPX) genes showed upregulation during NaCl treatment and coincide with antioxidant enzymes activities. Expression of Mitogen activated protein kinases-1 (MAPK-1), transcription factor WRKY53, Bax Inhibiotr-1 (BI-1), and nine Autophagy Related Genes (ATGs) were showed upregulation during NaCl treatment. Foliar spray of SA induced the expression of different genes in control and NaCl treated rice seedlings and suggested that SA helpful to alleviate the saline stress. The study suggested that SA is a potent signaling molecule not only with promotive effect on plants but may also be helpful to reduce the toxic effect of saline stress. Furthermore, study concludes that saline stress is regulated by multiple pathways including SA, MAPK1, Programmed Cell Death (PCD) and autophagy. These pathways may help to cope up with saline stress in rice seedlings.
Heat stress seriously inhibits plant growth and development through damage the photosynthetic components
and antioxidant enzymes functions. Salicylic acid (SA) is an important growth hormone regulator for combating
heat stress, but its roles in response to high temperature in tomato are largely unknown. The present study was
undertaken with a view to investigate the functional along with the potentiality of SA and how to nullify the
adverse effects of heat stress (42 °C) in tomato seedlings. Our findings revealed that supplementation of 1 mM SA
enhanced the gas exchange parameters (Pn, Gs, Ci, Tr, Ls), maximum quantum yield of photosystem II (Fv/Fm),
water use efficiency, reduced electrolyte leakage and increased the antioxidant enzymes (SOD, POD, CAT, and
APX) activity that helps to reduce oxidative damage through scavenging more reactive oxygen species (ROS)
which directly impacts on plants by protecting cell membrane from damage, higher chlorophyll content, lower
accumulation of lipid peroxidation, and H2O2. Additionally, exogenous application of SA increased the proline
content thus added on osmotic potential which influencing plants for better uptake of water that caused to
beneficial effects on stomatal aperture together with photosynthetic apparatus, whereas, high temperature re�duced leaf chlorophyll pigment, carotenoid content, leaf water potential, and osmotic potential. Taken together,
we concluded that the adverse effects of heat stress could be suppressed by pretreated SA through both in
increased photosynthesis activity and antioxidant enzymes functions.
Heat stress seriously inhibits plant growth and development through damage the photosynthetic components and antioxidant enzymes functions. Salicylic acid (SA) is an important growth hormone regulator for combating heat stress, but its roles in response to high temperature in tomato are largely unknown. The present study was undertaken with a view to investigate the functional along with the potentiality of SA and how to nullify the adverse effects of heat stress (42 °C) in tomato seedlings. Our findings revealed that supplementation of 1 mM SA enhanced the gas exchange parameters (Pn, Gs, Ci, Tr, Ls), maximum quantum yield of photosystem II (Fv/Fm), water use efficiency, reduced electrolyte leakage and increased the antioxidant enzymes (SOD, POD, CAT, and APX) activity that helps to reduce oxidative damage through scavenging more reactive oxygen species (ROS) which directly impacts on plants by protecting cell membrane from damage, higher chlorophyll content, lower accumulation of lipid peroxidation, and H2O2. Additionally, exogenous application of SA increased the proline content thus added on osmotic potential which influencing plants for better uptake of water that caused to beneficial effects on stomatal aperture together with photosynthetic apparatus, whereas, high temperature reduced leaf chlorophyll pigment, carotenoid content, leaf water potential, and osmotic potential. Taken together, we concluded that the adverse effects of heat stress could be suppressed by pretreated SA through both in increased photosynthesis activity and antioxidant enzymes functions.
Drought is a major concern for sustainable yield under changing environment. Soybean, an economically important oil and protein crop, is prone to drought resulting in yield instability. Salicylic acid (SA), a multifaceted growth hormone, modulates a series of parallel processes to confer drought tolerance thereby relieving yield limitations. The present study was performed in soybean plants treated with SA (0.5 mM) through seed pretreatment under drought regimes: severe stress (50% RWC) and moderate stress (75% RWC), and rehydration. Differential leaf proteome profiling with morphological, physiological and antioxidative metabolism studies were performed at two developmental stages (vegetative and flowering). This explained the tolerance attribution to soybean throughout the development attaining yield stability. Abundance of proteins involved in photosynthesis and ATP synthesis generated energy driving metabolic processes towards plant growth, development and stress acclimation. Carbon (C) metabolism proteins involved in growth, osmoregulation and C partition relieved drought-induced C impairment under SA. Defensive mechanisms against redox imbalance and protein misfolding and degradation under stress were enhanced as depicted by the abundance of proteins involved in redox balance and protein synthesis, assembly and degradation at vegetative stage. Redox signaling in chloroplast and its interplay with SA signaling triggered different defense responses as shown through thioredoxin protein abundance. Amino acid metabolism proteins abundance resulted in increased osmoprotectants accumulation like proline at initial stage which contributed later towards N (nitrogen) remobilization to developing sink. At later stage, abundance of these proteins maintained redox homeostasis and N remobilization for improved sink strength. The redox homeostasis was supported by the increased antioxidative metabolism in SA treated plants. The downregulation of proteins at flowering also contributed towards N remobilization. Yield potential was improved by SA under drought through acclimation with enhanced N and C remobilization to sink as demonstrated by increased yield parameters like seed number and weight per plant, thousand seed weight and harvest index. The potential of SA in conferring drought tolerance to plants to maintain sustainable yield possess future research interests.
A photo-induced cyclic peroxidation in isolated chloroplasts is described. In an osmotic buffered medium, chloroplasts upon illumination produce malondialdehyde (MDA)—a decomposition product of tri-unsaturated fatty acid hydroperoxides—bleach endogenous chlorophyll, and consume oxygen. These processes show (a) no reaction in the absence of illumination; (b) an initial lag phase upon illumination of 10-20 minutes duration; (c) a linear phase in which the rate is proportional to the square root of the light intensity; (d) cessation of reaction occurring within 3 minutes after illumination ceases; and (e) a termination phase after several hours of illumination. The kinetics of the above processes fit a cyclic peroxidation equation with velocity coefficients near those for chemical peroxidation.
The stoichiometry of MDA/O2 = 0.02, and O2/Chlbleached = 6.9 correlates well with MDA production efficiency in other biological systems and with the molar ratio of unsaturated fatty acids to chlorophyll. The energies of activation for the lag and linear phases are 17 and 0 kcal/mole, respectively, the same as that for autoxidation. During the linear phase of oxygen uptake the dependence upon temperature and O2 concentration indicates that during the reaction, oxygen tension at the site of peroxidation is 100-fold lower than in the aqueous phase.
It is concluded that isolated chloroplasts upon illumination can undergo a cyclic peroxidation initiated by the light absorbed by chlorophyll. Photoperoxidation results in a destruction of the chlorophyll and tri-unsaturated fatty acids of the chloroplast membranes.
The application of naturally occurring biologically active compounds could be an effective method to improve crop productivity under changing environmental conditions. In the present work the effects of priming maize seed with salicylic acid were tested on the grain yield under field conditions, and on the salicylic acid and polyamine metabolism under controlled environmental conditions. The field data suggested that the beneficial effects of pretreating maize seed with salicylic acid were mainly detectable in the yield in the case of early sowing dates. When young maize seedlings were exposed to low temperature stress, priming the seed with salicylic acid only modified the salicylic acid levels in the seed but not in the roots or leaves. The data suggested that salicylic acid was taken up by the seed and was then converted to bound forms. In contrast to salicylic acid, 5 days after sowing there was a substantial increase in the free form of ortho-hydroxy cinnamic acid in the seed, roots and leaves. Priming with salicylic acid also led to an increase in the putrescine content and a slight decrease in spermidine in the seed. The levels of putrescine, spermidine and spermine also increased in the roots of plants treated with salicylic acid under normal growth conditions. The results suggest that polyamines may also contribute to the stress tolerance of plants primed with salicylic acid.
The emergence of 22 commercial seed lots (12 in 2005 and 10 in 2006) of melon (Cucumis melo L.) with laboratory germinations greater than 90% were compared in low temperature (LTE), mechanical stress (MSE), high temperature (HTE), and salt stress (SSE) sowing conditions. The seedling emergence percentage ranged between 18% and 79% for LTE, 15% and 90% for MSE, 27% and 84% for HTE, and 49% and 92% for SSE in 2005; and 43% and 85% for LTE, 30% and 82% for MSE, 56% and 91% for HTE, and 49% and 89% for SSE in 2006. The germination of the lots was determined after controlled deterioration (CD) with 20% or 24% moisture content (MC) and accelerated aging (AA) at 40 and 45°C in 2005; or at 45 and 47°C in 2006 for 48, 72, 96, 120, and 144 h. Germination after various combinations of CD and AA was positively and significantly (P < 0.05) correlated with LTE, MSE, HTE, and SSE. Correlation values (0.17 to 0.78) of the initial laboratory germination were much lower than those of both aging tests. The optimum CD conditions of 48 h and 20% MC at 45°C and AA conditions of 120 h at 45 to 47°C are suggested as vigor tests to estimate relative seedling emergence of melon seeds.
Diquat was tested to determine its suitability for use as a preharvest desiccant of selected vegetable seed crops during 1997 and 1998. In separate studies, diquat was applied at 0, 0.56, or 1.12 kg·ha-1 a.i. to spinach (Spinacia oleracea L.), table beet (Beta vulgaris L.), and coriander (Coriandrum sativum L.) plants at usual swathing time. Except for beet seed in 1998, there was no clear trend toward reduced seed weight with increasing diquat rate. Spinach seed germination in 1998 and coriander seed germination in 1997 were reduced by diquat at 1.12 kg·ha-1 compared to seed from nontreated plants or plants treated with 0.56 kg·ha-1. In all crops, diquat at 0.56 kg·ha-1 was adequate for crop desiccation purposes. However, seed producers should consider the potential benefits from chemical desiccation that may potentially lower germination of the harvested seed. Chemical name used: 6,7-dihydrodipyrido[1,2-α:2′,1′-c]pyrazinediium ion (diquat).
MUMian (Bombax ceiba) is a deciduous tree that can grow in the dry-hot valley of southwestern China. However, natural regeneration of mumian is significantly inhibited by some factors such as high temperature that can accelerate seed deterioration. The objective of this study was to identify the change of seedling growth component(s) in response to seed aging at 45 degrees C either at low relative humidity (15%) or at high relative humidity (100%) for 0, 1, 2, 3, and 4 days. Germination assay results at 30 degrees C in darkness showed an interaction between relative humidity and aging duration. At high temperature and low relative humidity seedling growth, weight of used seed reserve and fraction of seed reserve depletion significantly decreased with increasing of aging duration. But the conversion efficiency of mobilized reserve to seedling tissues did not change significantly. In contrast, at high temperature and high relative humidity, seedling growth and conversion efficiency of seed reserve utilization decreased significantly, but weight of used seed reserve and fraction of seed reserve depletion did not change significantly until seeds were dead. It was concluded that there existed a different pattern of seed reserve utilization for seeds aged at low and high relative humidity, and humidification of seeds at 45 degrees C for 1 day is a possible way to increase germination of mumian.
This study was carried out in the Seed Research Laboratory of the Department of Crop Science, Ferdowsi University of Mashhad, Iran, in summer 2011. Rice (cv. Khazar) seeds were soaked in 0, 20, 50, and 100 mg l−1 salicylic acid (SA) aerated solutions for 24 h and then dried back to original moisture content and were sown in three temperatures (28°C as normal and 12°C and 8°C as chilling temperature conditions). In the first step, both treated and untreated seeds were sown at the optimum temperature (28°C). Then, to apply chilling temperature, 15 days after sowing, one set of the seeds was exposed to 12°C and 8°C under controlled conditions. Results showed that all seedlings raised from seeds primed with SA solutions produced a higher root and shoot length, final emergence percentage, and relative water content and also lower mean emergence time and time to 50% emergence (E50) in comparison with untreated seeds. Antioxidant enzyme system efficiently responded to the stress conditions and the priming treatment. Also seedling raised from primed seeds showed higher antioxidant activity at each temperature compared with control.
The effects of incorporation SA into KNO3 priming solution on the germination and emergence of eggplant seeds at 15°C were investigated. Seeds were primed into 3% KNO3 containing 0.05, 0.1, 0.5, or 1mM salicylic acid (SA) for 6 days, respectively. After the priming, seeds were either immediately used for germination and emergence test at 15°C or stored at 4°C for 1 month and then for the germination test. The primed eggplant seeds in general improved the final germination percentage (FGP), germination rate (G50), and germination synchrony (E10–90) at 15°C compared with non-priming seeds. Priming seeds in 3% KNO3 solution supplement with 0.1mM SA resulted in the best priming effect compared with other priming treatments and non-priming treatment, and all of the beneficial priming effects were still retained after stored at 4°C for 30 days. These results indicated that priming seeds in 3% KNO3 solution containing 0.1mM SA could be used as an effective method to improve low-temperature performance of eggplant seeds and subsequent seedling growth.
Aging during storage negatively affects rice seed viability and nutrition quality. Lipid degradation caused by phospholipase D (PLD) activity is known to be responsible for seed deterioration in Arabidopsis, but the mechanisms of this process in monocotyledonous plant rice remain unclear. In this study, we carried out lipid profiling analysis for rice seeds, and found that the main membrane lipids phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) declined during accelerated aging. In contrast, phosphatidic acid (PA), a hydrolysis product produced by PLD, increased. Interestingly, the degree of PA increase induced by accelerated aging (at 2 days) was much higher in rice than that in Arabidopsis (200% vs. 30%). Moreover, the decreased molecular species in PC and PE were well fit with those that were increased in PA, suggesting that PA may be derived from PLD-mediated lipid hydrolysis. OsPLDα1 and α3 were the major PLDαs in rice seeds, and their transcription increased significantly during the aging process. The aging treatment induced OsPLDα protein expression and activation. Three lipoxygenases (LOXs) were analyzed, and OsLOX2 transcription was induced significantly during seed aging. Our results reveal detailed information regarding lipid degradation during rice seed aging, and we go on to discuss the relationship between lipid degradation and peroxidation during seed aging.
Scientists engaged in seed research are often forced to refer to sequential developments of seedling growth in terms of days or hours after planting. Such terms are imprecise, because seedlings develop at different rates depending on seed condition, treatment, and environment. Fehr and coworkers in 1971 published an accurate and consistent description of soybean [Glycine mar (L.) Merr.] development from emergence to harvest maturity. Our objective was to devise a system of staging soybean seedling development up to emergence. Laboratory germination was conducted on four soybean cultivars, representing three maturity groups, in a specially designed germination apparatus. Rate of growth and seedling development were recorded at 6-h intervals between onset of imbibition and full seedling development. Six developmental stages were identified, based on distinct and consistent morphological changes. Adoption of this developmental staging system will allow more precise scientific communication regarding soybean development from the initiation of germination to emergence.
Understanding the cause of soybean [ Glycine max (L.) Merr.] seed deterioration during storage will assist in the development of accurate laboratory tests to evaluate seed vigor. This study was designed to investigate the changes that occur in mitochondria! respiration during the early stages of soybean seed deterioration. High‐quality seed lots of ‘Desoto’ and ‘Union’ soybean were stored at 25 °C and 115 g kg ‐1 seed moisture. Seed quality (germination and vigor) and conductivity of leachate from embryonic axes were measured at monthly intervals during storage. Mitochondrial State 3 (ST 3) respiration rates and respiratory control ratios (RCR) were measured from excised axes of samples after 24 h of imbibition. Germination remained high for seeds of both cultivars throughout storage; however, seed vigor (as measured by accelerated aging) declined significantly after 7 and 10 months for Union and Desoto, respectively. Conductivity of the leachate from excised axes for both cultivars increased early during storage prior to detectable changes in whole seed vigor. State 3 respiration rates of mitochondria from axes decreased throughout storage and RCR values declined after 2 months for Union and after 4 months for Desoto. Decreases in ST 3 respiration rates and RCR in both cultivars preceded measurable declines in whole‐seed vigor and correlated with increases in the conductivity of axes leachate.
Seed priming is a pre-germination strategy that improves seed performance and overcomes the negative effects associated with stress exposure. Seeds of capsicum (Capsicum annuum L.) cv. California Wonder were primed with warm water (WW, 40°C); CuSO4 (CU, 5mM), potassium nitrate (PN, 300 mM), and polyethylene glycol, PEG-6000 (PG, 16.7 mM), along with hydropriming (NW) and unsoaked (US) control to study the effect of seed priming. The seed priming significantly increased the rate as well as percentage of seed germination. Further, survival response of the seedlings obtained from primed seeds was better than the control on subsequent exposure to salt (NaCl 200 mM) or cold (4°C) stress for 10 days. All the plants obtained from potassium nitrate-primed seeds survived the salt-stress exposure, whereas those obtained from PEG-primed seeds tolerated both the cold and salt stresses. The control seedlings did not survive exposure to either stress. In addition, the growth performance of the plants obtained from primed seeds was better than control, suggesting chemical seed priming was a cost-effective and eco-friendly approach for developing cold or salt-stress tolerance in capsicum.
An experiment was carried out using an upland cotton (Gossypium hirsutum L.) cv. NIAB-78 to investigate the physiological and biochemical aspects of seed deterioration during accelerated ageing. The seeds were subjected to 40-44°C and 90-95% relative humidity for 1, 2, 3, 5, 7, 10, 15 and 20 days for artificial ageing. Controlled ageing linearly decreased the germination capacity. There was a complete loss of germination at 20 days of accelerated ageing. The decline in seed germination during accelerated ageing was accompanied with the increase in mean emergence time (MET), days to 50% germination (T50), electrical conductivity (EC) of solute leakage, free fat acidity and lipid peroxidation. Accelerated ageing not only affected emergence percentage and time but also decreased the seedling vigour, as is indicated by reduction in root weight, shoot weight and hypocotyl length. The cottonseed deterioration by accelerated ageing might be due to membrane disintegration and inactivation of enzymatic systems due to lipid peroxidation and increase in free fat acidity.
Germination and seedling growth of soybean (Glycine max L.) cv. Williams were examined on paper towels pre-moistened with a range of saline solutions (germination: 0–500 mMolal NaCl; seedling growth: 0–330 mMolal NaCl). The Na+, K+ and Ca2+ concentrations in the embryonic axis immediately before germination and in the seedling 3.5 d after germination were measured. Germination decreased at NaCl concentrations of 330 mMolal (81% germination) and above. At 420 mMolal NaCl, only 40% of seeds germinated, and at 500 mMolal NaCl there was no germination. Seedling growth rate decreased drastically with increasing salinity. At 220 mMolal NaCl, seedling growth rate had declined to 5% of the control, whereas at 330 mMolal NaCl seedling growth was almost zero 3–4 d after germination. Thus, soybean seeds were more tolerant of salinity in the germination than in the seedling phase. The results suggest that the greater tolerance of salinity during the germination phase might, in part, be the result of a lower sensitivity to high tissue Na+ concentrations. Germination (40%) was possible at a tissue Na+ concentration in the embryonic axis of 9.3 mg g FW-1, whereas seedling growth was completely inhibited at a tissue Na+ concentration of 6.1 mg g FW-1. Germination at higher tissue Na+ concentrations was associated with higher K+ and Ca2+ concentrations in the embryo axis, compared with growing seedlings, suggesting that these ions may protect the seeds in the pre-germination phase against salinity.
The optimum temperature for maize germination is between 25 and 28 °C. Poor and erratic germination at suboptimal temperature is the most important hindrance in its early sowing. This study was conducted to induce chilling tolerance in hybrid maize (Zea mays L.) by seed priming with salicylic acid (SA) and to unravel the background biochemical basis. For seed priming, maize hybrid (Hycorn 8288) seeds were soaked in 50, 100 and 150 ppm (mg l−1) aerated solutions of SA for 24 h and were dried back. Treated and untreated seeds were sown at 27 °C (optimal temperature) and at 15 °C (chilling stress) under controlled conditions. Performance of maize seedlings was hampered under chilling stress. But seed priming with SA improved the seedling emergence, root and shoot length, seedling fresh and dry weights, and leaf and root score considerably compared with control both at optimal and chilling temperatures. However, priming in 50 mg l−1 SA solution was more effective, followed by priming in 100 mg l−1 SA solution. Seed priming with SA improved the chilling tolerance in hybrid maize mainly by the activation of antioxidants (including catalase, superoxide dismutase and ascorbate peroxidase). Moreover, maintenance of high tissue water contents and reduced membrane permeability also contributed towards chilling tolerance.
Accelerated aging is known to reduce seed viability and vigor in many crop species. The phenomenon is due in part to aging-induced lipid peroxidation, which has the potential to damage membranes of the seed tissues. This study was undertaken to evaluate the effect of accelerated aging on germinability and several physiological characteristics related to peroxidation in the seed of two peanut cultivars. Accelerated aging was achieved by incubating seed at 45°C and 79% relative humidity in a closed chamber for 3, 6, or 9 days. The results indicate that accelerated aging inhibited seed germination and seedling growth. Enhanced lipid peroxidation and increased peroxide accumulation were observed in the axis and cotyledons of aged seed. Accelerated aging also inhibited the activity of superoxide dismutase, peroxidase, ascorbate peroxidase, and lipoxygenase. Seed axes appeared to be more susceptible to aging than cotyledons. The changes in germination and physiological activities, expressed as a function of aging duration, were similar in the two cultivars, despite differences in their seed weight.