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Effects of UV-irradiation on seed germination
Abstract
The advent of depletion of the ozone layer with the reported subsequent increase of UV-irradiation has led to heightened interest in the effects of UV light on cellular organisms. In this study, the effects of UV-irradiation was studied on the germination of kale, cabbage, radish and agave seeds. In all cases, UV light sped the germination of these seeds but the subsequent growth of the seedlings was markedly retarded. Pictures, taken at day 15, are presented to show this latter effect and the possible effects of UV-irradiation on seed germination are discussed.
... The seed coats of some plant species are more protective against UV-B than others (Tepfer & Leach, 2017). Thus, low to moderate doses of UV-B may not affect or may even increase seed germination, depending on the plant species (Noble, 2002), while high doses of UV-B radiation may reduce seed germination (Shaukat et al., 2013). In addition, solar radiation is thermal, from the extremely hot gasses of the sun, and this radiated heat can also have an effect on diseases (Mizubuti et al., 2000;Kanetis et al., 2010). ...
... However, lower UV-B doses from exposure times of 15, 30, 45 or 60 min or moderate UV-B doses of 2.83 or 3.75 kJ m À2 at %76°C (after 45 or 60 min of exposure), effective for seedborne disease control, did not reduce percentage germination compared with the untreated control. This result is in agreement with Noble (2002), who investigated the effect of UV-B irradiation on seeds of four species and found that germination was not affected. Other studies show that irradiation with a dose from 10 to 45 min of UV-B did not greatly affect the germination rate of buckwheat, Chinese cabbage, turnip, cabbage or parsley (Sugimoto, 2013). ...
... However, solar UV-B radiation also elicits a variety of acclimation responses, which typically include increased activity of antioxidant enzymes that serve as 'sunscreens' or UV filters (Caldwell et al., 2007). Peroxidase is an important component of the antioxidant defence system for scavenging H 2 O 2 (Noble, 2002) and is involved in cross-linking of cell wall components, polymerization of lignin and suberin monomers (Glazenner, 1982). Basra et al. (2004) showed that dry heat treatment of cotton seed at 80°C for 8 h enhanced physiological and biochemical aspects of seedlings that had a photoprotective function. ...
Treatment of anthracnose infected lupin seed with doses of solar UV‐B radiation plus temperature collected in a solar oven covered with a UV‐B blocking film decreased this seed borne pathogen. To test the hypothesis that solar UV‐B radiation plus temperature decreases infection of Colletotrichum acutatum, lupin seed lots infected seed were placed in the oven and exposed on sunny days for 15, 30, 45, 60, 75, 90, and 120 min. The degree of disease incidence reduction and seed germination was dependent on the exposure time. Exposures times of 75 min (UV‐B 4.41 kJ/m2 ≈ 76°C) and higher reduced incidence from 5.0% to undetectable levels, but also reduce seed germination by around 10% compared with no treated seed. Thus, in a second set of experiments, infected seed were exposed for 45 or 60 min in the solar oven (UV‐B 2.83 or 3.75 kJ/m2, respectively ≈ 76°C), for 60 min at ambient (UV‐B 3.75 kJ/m2 ≈ 21°C), and to dry heat 75°C. Exposures for 60 min in the solar oven reduced seed infection by 99%, while isolated dry‐heat or UV‐B radiated seed reduced infection by 32 and 60%, respectively. To evaluate the effect of UV‐B plus temperature, lupin seed exposed to 45 or 60 min were grown and physiology and biochemistry responses assessed in seedlings. These exposure time increased total concentrations of chlorophyll, protein and peroxidase activity in seedlings compared with those grown from infected seed. This article is protected by copyright. All rights reserved.
... This approach produces the highest biomass accumulation when compared to LEDs exclusive exposure ). Seeds exposed to UV-B germinate faster, although continuous irradiation delays later vegetative growth (Noble, 2002). Exposing seedlings to white fluorescent light for 10 days, in contrast to darkness, results in the accumulation of a higher number of carotenoid species and at considerable higher levels (Tuan et al., 2012). ...
... Responses to light depend on developmental stage, light quantity/quality and the cultivar tested. Continuous exposure to UV-B accelerates seed germination but delays later development (Noble, 2002). UV-B modifies flavonoid profiles when applied as a supplement over white light for 1 day at pre-harvest stages (Neugart et al., 2012). ...
... The rationale of this research work was to assess ozone layer thinning negative effects on radish grown in natural conditions. A similar question revealed that continuously UV-B-irradiated radish seeds display increased germination rates, compared to white fluorescent light, but result in lower plant fitness later during development (Noble, 2002). Using precise UV-B irradiation dosage and timing can possibly allow producing enhanced radish plants. ...
Light is a potent regulator of plant growth and development, impacting gene expression to global physiology and metabolism. Plants sense a broad range of wavelengths, from UV to far-red, through separate photoreceptors. These light sensors direct adaptive responses under changing environmental conditions and specifically activate precise downstream signaling pathways. Research studies in photobiology, mostly in Arabidopsis thaliana, have characterized light effects on many plant behaviors, along with the genetic mechanisms that control them. Transferring this knowledge to crops has opened a new field in plant science where variation in light quantity, quality, duration or combinations can be used to change plant growth, development or metabolism to influence a desired final product. With the potential of easily being introduced into production chains, and given its safety and relative low cost, this approach can be combined with, or used as an alternative to, breeding or genetic engineering. We review how light has been used in 22 different crop species to manipulate growth characteristics, nutritional value, and yield. We also discuss future opportunities in using light to control produce quality or timing of plant product production.
... UV-Irradiation: UV-B irradiation has some activity on the surface of the seed cells, stimulating rapid germination [62]. In a study by Lee et al. [63], UV-B radiation was applied to R. rugosa seedlings for 5, 10, and 30 min. ...
... The inner cells of the seed appeared to be harmed by excessive UV-B exposure. In the germination study [62], such an effect was more or less expected. Finding the homeosis stage will be crucial to enhancing germination, but it will not be realistic due to the varied pericarp thickness of each seed caused by different cross-combinations. ...
Seed germination is a crucial stage in the life cycle of plants, and understanding the factors influencing germination is essential for successful cultivation, plant breeding, and conservation efforts. The genus Rosa, commonly known as roses, encompasses a diverse group of flowering plants renowned for their beauty and fragrance. Rosa germination is influenced by a variety of factors, including seed dormancy, environmental conditions, and seed treatments. Many Rosa species exhibit different types of seed dormancy, such as physical dormancy caused by hard seed coats and physiological dormancy due to internal mechanisms. Overcoming seed dormancy often requires specific treatments, including cold stratification, scarification, or chemical treatments, to promote germination. Environmental factors, including temperature, moisture, light, and substrate, play vital roles in Rosa germination. Temperatures ranging from 15 to 25 °C, moisture, and exposure to light or darkness, depending on the species, constitute suitable conditions for seed germination. Many studies have been conducted to investigate the germination requirements of different Rosa species, thereby expanding our understanding of their propagation and conservation. Additionally, advancements in techniques such as in vitro germination and molecular approaches have further enhanced our understanding of Rosa germination biology.
... Hence, when seeds are exposed to UV light, it breaks the seed coat and induces GP. The UV-B portion of the EM spectrum has the potential to cause rapid germination of seeds by breaking the seed coat (Noble, 2002). However, the germination percentage and germination time vary based on the type of seed. ...
... For example, when kale, agave, cabbage, and radish (20 seeds each) seeds were treated using UV-B light (Manufacturer: Philips, Power: 10 W, 10 00 distance), 6, 15, 15 and 18 seeds were germinated after 24, 96, 48 and 24 h respectively; Whereas, only 0, 10, 10 and 16 seeds germinated in visible light treated samples. Similar effects were seen in thuja (GP increase 12.8%) and picea Fennica (GP increase 24%) seeds after UV treatment (Noble, 2002;Kondrateva et al., 2019). ...
According to United Nations Department of Economic and Social Affairs (UN DESA), the current food production will not be sufficient to feed the rapidly growing human population in the near future. Thus, the current focus of the food and agricultural sectors is to increase food production to meet future food demands with the help of novel and existing post-harvest processing methods. However, food sustainability has to be achieved without compromising the quality of food, public health and environmental safety. Hence, the application of sustainable food processing and preservation methods such as Ohmic heating, infrared heating and UV light technology started gaining popularity among the agri-food sectors. These technologies can improve various processes and applications such as seed germination, microbial reduction, shelf-life enhancement, drying, dehydration, blanching, roasting, extraction, enzyme inactivation. Though existing conventional processes can help in pre and post-harvest applications, sustainable processing operations like Ohmic heating, infrared heating and UV light technology provide the end products with superior quality as compared to conventional methods. Furthermore, these techniques are efficient. Thus, they save processing time, energy, water, resources and cost of operation.
... An important factor affecting seed germination and plant growth refer to their contamination degree, [1,[18][19][20][21]51] a feature that can be positively decreased by the plasma treatments as a prevention method. [5,18,19,49] Figure 2a shows the contamination degree, defined and determined as described in the experimental section, for the plasmatreated seeds, the control set, and the dry seeds. ...
... Clearly, plasma and drying treatments induce a net reduction in contamination degree with the expected benefits for seeds storage and conservation and/or their germination success. [18,19,[51][52][53] However, whether equivalent factors are involved in reducing the contamination degree in both situations is still a subject of debate, although we presume that the oxidative character of the plasma should play a specific role in the plasma case. ...
Acceleration in germination time by 12–24 h for barley seeds treated with atmospheric air plasmas may have a significant economic impact on malting processes. In this study, the increase in germination rate and decrease in contamination level upon plasma treatment could not be directly correlated with any significant increase in the water uptake capacity, except for seeds exposed to mild drying treatment. A variety of germination essays have been carried out with seeds impregnated with an abscisic acid solution, a retarding factor of germination, treated with a peroxide solution, and/or subjected to the plasma and drying treatments. Results suggest that plasma and hydrogen peroxide treatments induce the formation of reactive oxygen and nitrogen species that affects the abscisic acid factor and accelerate the germination rate. Air plasma treatment of barley seeds enhances the germination rate even if they are saturated with abscisic acid, an intrinsic germination retardant. Similar to the effects of a hydrogen peroxide treatment, plasma implies the generation of oxygen and nitrogen species without changes in the topography. The hydrophilic behavior induced by the plasma has not had repercussions on the water uptake of the seeds, unlike what happens with a drying treatment.
... In previous studies, an increase of germination parameters was also observed in kale (Brassica oleracea L.), radish (Raphanus sativus L.) and agave (Agave tequilana F.A.C. Weber.) (Noble, 2002), chickpea (Cicer arietinum L.) (Maity et al., 2010), burdock (Arctium lappa L.), pea (Pisum sativum L.), spinach (Spinacia oleracea L.) and onion (Allium cepa L.) (Debnath et al., 2020). In another study, germination of Silene vulgaris (Moench) Garcke seeds was unaffected by UV-B exposure (Van de Staaij, 1997). ...
... Researchers studied the effects of UV radiation on Lactuca sativa L. seeds and noted a significant germination improvement (Zhang et al., 2019). Noble (2002) reported the impact of UV-B rays on three plant genera and found that germination was not influenced by this treatment. The testa is, possibly, responsible for the notable embryo preservation. ...
Concerning the increasing level of ultraviolet (UV) radiation in many parts of the world, researching plant establishment under UV exposure is an essential subject. This experiment was aimed at exploring the effects of UV-B on the germination rate, seedling length, radix and stem's length, seedling's fresh/dry weight, and germination indices of Scrophularia striata seeds (Scrophulariaceae), a native medicinal plant from Iran. Treatments included UV-B exposure times (0/control, 15, 30, and 45 min) on two different ecotypes of S. striata including Lizan (LE) and Pahleh (PE). The UV-B radiation treatment for 45 min significantly enhanced the final germination percentage (FGP) of PE seeds. Maximum TSG (time spread of germination) was achieved under 45 min UV exposure (3.67 Day) in PE, while in LE, increasing radiation caused a significant reduction in TSG. Regarding principle component analysis, PE showed better germination indices under UV-B radiation. The seedling length of S. striata was remarkably changed by UV-B treatment; in this case, enhanced seedling length was observed in LE than PE. The UV-B exposure can have promotive effects on many important germination indices in seeds and some seedling growth parameters in S. striata ecotypes, and this effect could be related to the ecotype differences and ecotype-specific responses.
... Seeds of some plant species have seed coats that are more resistant to UV-B rays [74]. In this sense, depending on the plant species, low to moderate doses of UV-B may not re-duce seed germination, and may even increase it [75], whereas high doses of UV-B radiation can reduce seed germination [76]. In addition, solar radiation generates heat, and this radiated energy can also have an effect on disease [77,78]. ...
... However, moderate exposure times of 45 min, effective for seed borne disease control, do not reduce germination percentage [56]. Germination percentages of buckwheat, Chinese cabbage, turnip, cabbage, or parsley seeds were not greatly reduced with UV-B exposure times from 10 to 45 min [75]. New studies could elucidate the combined effect of UV-B and high temperature on seed invigoration and its potential expression into positive responses in the plant. ...
Here we propose modern alternatives for the management of the most devastating disease of this Andean legume of high nutritional value.
... In a study carried out in Germany, a UV open and a UV blocking plexiglass cover were compared in order to investigate their effect on sunflower (Helianthus annuus L.) growth, and it was found that the hypocotyl length was reduced by 50% under the UV blocking material [41]. Hypocotyl elongation growth is an essential step in the seed germination and a key characteristic for plant emergence, influenced by environmental conditions, phytohormones, and is varying among genotypes [64]. ...
... Thus, according to the above, UV blocking covering materials would have a suppressive effect on the growth and development of the germination process, due to the fact that UVB radiation photons are more energetic than visible light photons and, hence, have a stronger effect on the surface of plant cells, causing the ultimate breakdown of seed coating allowing germination to occur [64]. ...
Pure polyethylene (PE) is enriched with several additives to make it a smart application material in protected cultivation, as a cover material for either greenhouses or screenhouses. When this material completely or partially absorbs ultraviolet (UV) solar radiation, then it is called UV blocking material. The current work presents a review on the effects of the UV blocking covering materials on crop growth and development. Despite the passage of several years and the evolution of the design technology of plastic greenhouse covers, UV blocking materials have not ceased to be a rather interesting technique for the protection of several vegetable and ornamental species. Much of the research on UV blocking materials focuses on their indisputable effect on reducing the activity of pests and viral-related diseases, rather than on the effects on the crop physiology itself. In the present paper, representative studies dealing with the effect of the UV blocking materials on the agronomic factors of different crops are presented and discussed. The results reveal that UV blocking materials have mainly positive effects on the different plant physiological functions, such as photosynthesis and transpiration rate, and on growth characteristics, while they might have a negative effect on the production and content of secondary compounds, as anthocyanins and total phenolics.
... Regarding the use of UV-A/B in tomato culture technology, we have recently demonstrated the beneficial impacts of moderate UV supplementation on plants' flowering and fruit ripening, with minimal impacts on photosynthesis, and a controlled stimulation of the phenylpropanoid pathway (Ponte et al., 2017). How UV intensity and type modulate the seed biology and germination remains a matter of debate (Araújo et al., 2016a;Nangle et al., 2012;Noble, 2002). ...
... Nangle et al. (2012) showed that seeds of Sugimoto (2013) demonstrated that an irradiation of ∼2 J m −2 s −1 promoted a species' dependent response, with a delay of germination in e.g., eggplant, lettuce, pea and spinach, and an acceleration in buckwheat and carrot. A similar species dependency was reported by Noble (2002) in others species (e.g., red Russian kale and cherry bell reddish). Tomato seedlings demonstrated, in general, an increase of biomass in response to UV-A 2H, shown by an increase in the shoot and root length, cotyledon leaf area, and fresh and dry matter content. ...
The production, processing and consumption of Solanum lycopersicum L. fruits are increasing worldwide, demanding technologies to improve tomato growth efficiency. Germination is a critical step for intensification of crop production and conditions plants’ vigor, a crucial benchmark in plant market. Ultraviolet radiation supplementation is emerging in seed technology as it increases plant growth with no impact on the environment, although its use in crops’ nurseries still remains an open field. In the present work, seeds/seedlings of three commercial cultivars (‘Oxheart’, ‘Cherry’ and ‘Roma’) were grown for 15 days under three different ultraviolet (UV)-conditions. The results demonstrated the benefits of supplementing seeds/seedlings with moderate UV-A dose, being evident an acceleration/synchronization of germination rates, higher biomass and cotyledon area, and a stimulation of photosynthetic pigments and anthocyanins in all cultivars analysed. UV-B showed a cultivar dependence effect: ‘Cherry’ cultivar was in general not affected by the moderate UV-B dose used, but ‘Roma’ and ‘Oxheart’ showed a delay in germination and a seedling biomass decrease, in parallel with a decrease in chlorophylls and carotenoids. Both UV-A/B supplements reduced the H2O2 and MDA seedling levels, but the antioxidant battery was stimulated (e.g., peroxidases that use guaiacol as a substrate (GPX)) as well as the phenol level and the antiradical activity. The Principal Component Analysis (PCA) validates the clear distinction between cultivars and UV-condition effects. These data demonstrate the benefits of UV-A supplementation of tomato seeds pointing out to an “eustress” beneficial of UV-A in seedlings growth and vigor. A possible application of UV-A supplementation to other crops is discussed.
... Lactuca sativa showed improved seed germination when exposed to 254, 265, 334 and 405 nm of radiations as compared to those grown in dark [43]. However, rapid seed germination and highly branched roots were observed in kale, cabbage, radish and agave seeds when treated with UV radiation when compared to the control [44]. A study on cotton (Gossypium hirsutum) showed that excess UV-B damages the developing shoots of cotton resulting in the reduction of dry matter, Zn mobilization and leaf expansion [45]. ...
... All the species respond differently to UV-B radiation under different experimental approaches as the effects are either stimulating, depressing, or have no effect on their growth and physiology [8,19,[42][43][44][45][46]. Availability of water influences the effect of UV-B on bryophytes as these are poikilohydric and unavailability of water causes leaf cells to dry out and ceases the metabolism [47]. ...
Ozone (O 3) is a stratospheric layer that plays important role in providing support to humans for their survival. It is an essential factor for many global, biological and environmental phenomena. The ultraviolet (UV) rays emitted from sun are captured by ozone and thereby provide a stable ontological structure in the biosphere. Various anthropogenic activities such as emissions of CFCs, HCFCs and other organo-halogens lead to the depletion of ozone. The ozone depletion resulted in secondary production of an ozone layer near the ground (terrestrial ozone layer), which is responsible for adverse effects on plants, humans and environment with increased number of bronchial diseases in humans. The mutations caused by UV rays result in variation in morphogenic traits of plants which ultimately decreases crop productivity. However, UV radiation is required in optimum intensity for both plants and animals. This review takes into an account the wide ranging effects of ozone depletion with a majority of them being detrimental to the plant system.
... Ultraviolet-C (UV-C) light inhibited germination in sunflower (Helianthus annuus L.), but this effect could be reversed during dark storage of seeds aer the UV-C treatment (Torres et al., 1991). Kale, cabbage (Brassica oleracea L.), radish (Raphanus sativus L.) and agave (Agave sp.) treated with UV-B light germinated more rapidly, but subsequent growth was markedly inhibited (Noble, 2002). ere was no benefit to germination in a range of vegetable and field crops including tomato (Solanum lycopersicum L.) and soybean [Glycine max (L.) Merr.] treated with UV-B irradiation (Krizek, 1975), and no beneficial effect on germination of Bromus catharticus Vahl from exposure to UV-B (Deckmyn and Impens, 1998). ...
... e variation in response to UV treatments between the two seed lots underscored the need to determine if a clear benefit due to UV irradiance exists. Results of lot 1 were very promising and agree with test results on lettuce (Lactuca sativa L.) and wheat (Triticum sp.) seeds (Wagné, 1966;Noble, 2002). e amount of published work on UV light effects on turfgrass germination remains limited, and effect of variability among seed lots due to age and weight, as noted previously, regardless of light treatment, should be studied further (Shaidaee et al., 1969;Larsen and Andreasen, 2004). ...
Kentucky bluegrass (Poa pratensis L.) is a commonly used turfgrass in the temperate climates of the United States. The grass is predominantly established from sod because of its slow germination (21 d). Ultraviolet (UV) light has been noted to enhance germination speed of other crops and it may similarly enhance Kentucky bluegrass germination. Turfgrass seeds from two seed lots were placed in two separate germination chambers and set on an 8 h light/16 h dark schedule. One chamber received only visible light while the other received a supplemental UV light treatment (11.2 kJ m − 2 d − 1). The treatments were applied for 21 d. Seed germination was counted at 7, 14 and 21 d. Ultraviolet light increased germination capacity and speed in the newer but not older seed lot. Seed germination was greater (p ≤ 0.05) at day 7, and after 21 d germination was higher in UV light conditions than in control. These results suggest that treatment of bluegrass seed with UV light may enhance germination, although seed age may override the effect.
... This effect, however, can be reversed during dark storage of seeds after the UV-C treatment (Torres et al., 1991). Kale, cabbage, (Brassica oleracea), radish (Raphanus sativus L.) and agave (Agave L) treated with UV-B light germinated more rapidly but subsequent growth was markedly inhibited (Noble, 2002). The number of seeds and dry weight of seeds in Bromus catharticus receiving 90% UV-B almost doubled compared to the control . ...
... The variation between the seed lots means that further work is required in order to conclusively determine if a clear benefit due to UV irradiance exists. The initial results were very promising and agree with data produced from lettuce and wheat seed (Noble, 2002, Wagné, 1966. The amount of published work done with ultraviolet light on turfgrass germination is limited and variability in seed lots due to age and weight has been noted previously regardless of light treatment Andreasen, 2004, Shaidaee et al., 1969). ...
... The emerging root system is usually exposed to sunlight during the seed germination process due to abiotic factors such as rain and wind, as well as biotic factors such as animal activity (Grundy et al., 2003;Yokawa et al., 2016;Wan et al., 2018). Despite some studies reporting on the morphological, anatomical, physiological, biochemical, and molecular responses of plants to UV-B, there are still very few reports on seed germination under UV-B (Noble, 2002;Hamid et al., 2019;Jaiswal et al., 2020;Ozel et al., 2021;Mousavi et al., 2022;Rai and Agrawal, 2022). ...
Understanding the behaviour of halophyte seed germination under multiple abiotic stressors is crucial for restoring salt-affected lands. Zygophyllum album L. (syn. Tetraena alba (L.f.) Beier & Thulin) is a perennial halophytic species that spreads in the coastal ecosystems of Mediterranean areas. Halophytes' seed germination indices concerning the influence of UV-B remain unexplored in scientific investigations. We provide here data on the effects of salinity (0, 100, 200, and 400 mM NaCl) and light (total darkness, 12 h dark/12 h light, and 12 h dark + 9 h light + 3 h UV-B) on seed germination, seedling growth parameters, antioxidant enzymes, histochemical localization of O2−, and anatomical parameters of Z. album. The germination percentage was not significantly decreased under low and medium salinities (100 and 200 mM NaCl), but germination was entirely inhibited at 400 mM NaCl. Also, seed germination was reduced significantly under the combined treatment of 200 mM NaCl and UV-B light. The germination rate was significantly decreased at low salinity in darkness and under moderate salinity with all light treatments. However, the highest germination recovery was recorded under combined salinity and UV-B treatments. At the seedling stage, salinity reduced biomass and seedling length under all light treatments. Additionally, combined UV-B with salinity treatments had a negative synergistic influence on all growth parameters. On the other hand, the increase of catalase and peroxidase activities, as well as the accumulation of druses and idioblasts under combined treatment, suggest a trade-off between the growth of this species and its defense mechanisms. These results indicate that Z. album has a moderate tolerance to both salinity and UV-B stresses during germination, highlighting its significance as a potential source for reclaiming salt-affected lands and cultivating crops under future climate changes.
... The results reported by other authors reveal diverse relations between wheat seed germination energy and the type of microflora in the environment, including a non- It is difficult to clearly conclude whether some changes may be induced primarily by the lack/presence of microflora or by UV-C radiation itself. It should be noted that longterm exposure to UV light shortens the germination process and subsequently deforms the seedlings [48]. Permanent exposure may interrupt germination altogether. ...
Metalloenzymes play an important role in the regulation of many biological functions. An effective way to prevent deficiencies of essential minerals in human diets is the biofortification of plant materials. The process of enriching crop sprouts under hydroponic conditions is the easiest and cheapest to conduct and control. In this study, the sprouts of the wheat (Triticum aestivum L.) varieties Arkadia and Tonacja underwent biofortification with Fe, Zn, Mg, and Cr solutions in hydroponic media at four concentrations (0, 50, 100, and 200 µg g−1) over four and seven days. Moreover, this study is the first to combine sprout biofortification with UV-C (λ = 254 nm) radiation treatment for seed surface sterilization. The results showed that UV-C radiation was effective in suppressing seed germination contamination by microorganisms. The seed germination energy was slightly affected by UV-C radiation but remained at a high level (79–95%). The influence of this non-chemical sterilization process on seeds was tested in an innovative manner using a scanning electron microscope (SEM) and EXAKT thin-section cutting. The applied sterilization process reduced neither the growth and development of sprouts nor nutrient bioassimilation. In general, wheat sprouts easily accumulate Fe, Zn, Mg, and Cr during the applied growth period. A very strong correlation between the ion concentration in the media and microelement assimilation in the plant tissues (R2 > 0.9) was detected. The results of the quantitative ion assays performed with atomic absorption spectrometry (AAS) using the flame atomization method were correlated with the morphological evaluation of sprouts in order to determine the optimum concentration of individual elements in the hydroponic solution. The best conditions were indicated for 7-day cultivation in 100 µg g−1 of solutions with Fe (218% and 322% better nutrient accumulation in comparison to the control condition) and Zn (19 and 29 times richer in zinc concentration compared to the sprouts without supplementation). The maximum plant product biofortification with magnesium did not exceed 40% in intensity compared to the control sample. The best-developed sprouts were grown in the solution with 50 µg g−1 of Cr. In contrast, the concentration of 200 µg g−1 was clearly toxic to the wheat sprouts.
... UV-B was shown to increase the germination rate of safflower (Carthamus tinctorious), radish, cabbage, kale, and agave seeds [140]. However, prolonged exposure to UV-B inhibits the growth of seedlings [140,141]. UV-C treatment in maize and sugar beet was also shown to increase germination rate and seedling growth [142]. During plasma treatment, the possibility that UV light directly affects seed germination is considered very low due to its short exposure duration and low intensity of irradiation from the plasma sources. ...
Low-temperature atmospheric pressure plasma has been used in various fields such as plasma medicine, agriculture, food safety and storage, and food manufacturing. In the field of plasma agriculture, plasma treatment improves seed germination, plant growth, and resistance to abiotic and biotic stresses, allows pesticide removal, and enhances biomass and yield. Currently, the complex molecular mechanisms of plasma treatment in plasma agriculture are fully unexplored, especially those related to seed germination and plant growth. Therefore, in this review, we have summarized the current progress in the application of the plasma treatment technique in plants, including plasma treatment methods, physical and chemical effects, and the molecular mechanism underlying the effects of low-temperature plasma treatment. Additionally, we have discussed the interactions between plasma and seed germination that occur through seed coat modification, reactive species, seed sterilization, heat, and UV radiation in correlation with molecular phenomena, including transcriptional and epigenetic regulation. This review aims to present the mechanisms underlying the effects of plasma treatment and to discuss the potential applications of plasma as a powerful tool, priming agent, elicitor or inducer, and disinfectant in the future.
... In the last decade, a variety of physical, chemical, and combination intervention methods have been used to promote seed germination and sprout development, including gamma irradiation, electromagnetic fields, and UV treatment [3][4][5]. However, these technologies are linked to several major negative consequences, including expensive costs, long processing times, chemical residues in the environment, and environmental concerns. ...
The present study reports the generation of plasma-activated water (PAW) using dielectric barrier discharge (DBD), its physicochemical properties, and its potential impact on the seed germination and seedling growth of soybean. The results revealed significant changes in physical parameters, such as pH, total dissolved solids, total suspended solids, turbidity, conductivity, dissolved oxygen, and chemical parameters, such as calcium, chromium, sodium, manganese, nitrate, nitrites, phosphorus, and sulfur and biological parameter such as E. coli in water after plasma treatment. The concentration of dissolved oxygen, conductivity, nitrate, nitrite, and sulfur was increased with an increase in water treatment time, and the amounts of the other analyzed parameters decreased with the increase in water treatment time. The effects of untreated water and plasma-activated water treated for 20 minutes on soybean germination and growth were studied. The germination rate was found to be higher with plasma-treated water. Shoot lengths, seedlings length, vigor index, and germination rates were increased as compared to those germinated by normal water irrigation. The seedlings irrigated with PAW responded to the abundance of nitrogen by producing intensely green leaves because of their increased chlorophyll a as compared to seedlings irrigated with normal water. However, the content of chlorophyll b and carotenoids was found to decrease in the case of seedlings irrigated with PAW. Based on this report, we conclude that PAW could be used to substantially enhance seed germination and seedling growth.
... El UV-B ha demostrado que afecta el crecimiento y la morfología de las plantas (Ma y col., 2018). Esta tecnología no solamente busca generar seguridad en alimentos, si no también mejorar su calidad para el beneficio de la salud humana (Koutchma, 2021) así como originar la inactividad de bacterias, parásitos, esporas bacterianas, entre otros (Noble, 2002). ...
In recent years there has been a shortage of food due to overpopulation, lack of natural resources, climate change, among other factors. Lack of food has been one of the biggest problems in the world, so supporting millions of people is a challenge. Currently there are a wide variety of emerging technologies that can help improve processes in the agri-food sector. One of the newest technologies is cold plasma which, if applied to the surface of various substrates, can lead to the improvement of the properties or applications that are being sought. This technology could be of great interest in the agri-food sector because if the superficial modification of seeds is sought, this could be translated into the improvement of water uptake and nutritional content and thus achieve a greater organization in these processes, which It could be reflected in a greater production of vegetables and the fight against insufficient food.
... Effective sterilization is a known effect of nitrogen-rich high-pressure plasmas, which has been attributed to the effect of UV radiation [42], likely through the rupture of the microbial genetic material [43]. It is known that energetic UV photons speed up the germination process due to the breakdown of seed coatings, although they have other associated effects such as retarded seedling growth and root damage [44,45]. However, under our working conditions, UV photons of low intensity are mainly associated with the weak emission lines due to the second positive system of activated N 2 * species ( figure 1) and, consequently, a substantial effect on germination can be discarded. ...
Plasma technology has emerged as an efficient, simple, and eco-friendly method for activating seed germination processes. Most studies on this subject have focused on the morphological and wetting effects on the surface state of seeds and attributed the improvement in germination occasionally found to the induced hydrophilicity and a higher water imbibition rate. Recently, the involvement of reactive oxygen and nitrogen species in the germination process has also been highlighted. In this work, we study the effect of a very low-power cold atmospheric air-plasma treatment on the germination and sterilization of cotton seeds in normal (i.e., water abundant) and simulated drought conditions. Optical emission spectroscopy of the plasma has revealed the formation of different excited species of molecular nitrogen and oxygen, as well as OH and NO radicals that are deemed responsible for the chemical functionalization and slight morphological changes observed on the surfaces of cotton seeds. The physicochemical changes of the seed surface were analyzed by scanning electron microscopy, energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), and x-ray photoemission spectroscopy. This latter technique has shown the formation of a high surface concentration of oxygenated (i.e. -CO x, -C-OH, -O x ) and oxinitrided (i.e. -NO x ) functional groups which disappear from the surface upon exposure to vapor or liquid water. This process must entail the diffusion of these species (together with that of potassium ions that were plasma segregated to the surface) into the interior of seeds. The fact that the water uptake capacity of seeds is not significantly modified by the plasma treatment suggests that the observed in-diffusion of active oxygen and nitrogen species is an important factor in the enhancement of germination capacity induced by plasma activation, particularly under conditions of water scarcity, where germination differences of more than 60% could be found between pristine and plasma-treated seeds. The analysis by FT-IR of the adsorption of deuterated water (D2O) molecules is proposed as a useful procedure to directly monitor water uptake/release processes from seed surfaces.
... It is known that just UV-B can accelerate germination of safflower seeds but then negatively affects growth [112]. Noble [113] made the same conclusions with kale, cabbage, radish and agave seeds. Likewise, Sadeghianfar et al. [114] showed accelerated germination of maize and sugar with UV-C treatment but instead, saw an increase in plant growth parameters and suspected this may be due to breaking down the seed coat and increase in temperature. ...
Plasma treatments are currently being assessed as a seed processing technology for agricultural purposes where seeds are typically subjected to pre-sowing treatments to improve the likelihood of timely and uniform germination. The aim of this review is to summarize the hypotheses and present the evidence to date of how plasma treatments affect seeds, considering that there is difficulty in standardizing the methodology in this interdisciplinary field given the plethora of variables in the experimental setup of the plasma device and handling of biological samples. The ever increasing interest for plasma agriculture drives the need for a review dedicated to seeds, which is understandable to an interdisciplinary audience of biologists and plasma physicists. Seeds are the first step of the agricultural cycle and at this stage, the plant can be given the highest probability of establishment, despite environmental conditions, to exploit the genetic potential of the seed. Furthermore, seedlings seem to be too sensitive to the oxidation of plasma and therefore, seeds seem to be the ideal target. This review intentionally does not include seed disinfection and sterilization due to already existing reviews. Instead, a summary of the mechanisms of how plasma may be affecting the seed and its germination and developmental properties will be provided and discussed.
... UV-B light is an inherent component of sunlight that strongly affects plant development [1,2]. The UV-B photoreceptor UVR8 (UV resistance locus 8) is required for UV-B responses in plants [3]. ...
Background:
UV-B signaling in plants is mediated by UVR8, which interacts with transcriptional factors to induce root morphogenesis. However, research on the downstream molecules of UVR8 signaling in roots is still scarce. As a wide range of functional cytoskeletons, how actin filaments respond to UV-B-induced root morphogenesis has not been reported. The aim of this study was to investigate the effect of actin filaments on root morphogenesis under UV-B and hydrogen peroxide exposure in Arabidopsis.
Results:
A Lifeact-Venus fusion protein was used to stain actin filaments in Arabidopsis. The results showed that UV-B inhibited hypocotyl and root elongation and caused an increase in H2O2 content only in the root but not in the hypocotyl. Additionally, the actin filaments in hypocotyls diffused under UV-B exposure but were gathered in a bundle under the control conditions in either Lifeact-Venus or uvr8 plants. Exogenous H2O2 inhibited root elongation in a dose-dependent manner. The actin filaments changed their distribution from filamentous to punctate in the root tips and mature regions at a lower concentration of H2O2 but aggregated into thick bundles with an abnormal orientation at H2O2 concentrations up to 2 mM. In the root elongation zone, the actin filament arrangement changed from lateral to longitudinal after exposure to H2O2. Actin filaments in the root tip and elongation zone were depolymerized into puncta under UV-B exposure, which showed the same tendency as the low-concentration treatments. The actin filaments were hardly filamentous in the maturation zone. The dynamics of actin filaments in the uvr8 group under UV-B exposure were close to those of the control group.
Conclusions:
The results indicate that UV-B inhibited Arabidopsis hypocotyl elongation by reorganizing actin filaments from bundles to a loose arrangement, which was not related to H2O2. UV-B disrupted the dynamics of actin filaments by changing the H2O2 level in Arabidopsis roots. All these results provide an experimental basis for investigating the interaction of UV-B signaling with the cytoskeleton.
... (2005) hıyar fidelerinde büyüme ve gelişmenin UV uygulaması ile önemli ölçüde azaldığını ifade etmişlerdir. Aynı şekilde, farklı çalışmalarda UV uygulamasının bitki gelişimine olumsuz etkileri olduğu bildirilmiştir (Noble, 2002;Mahdavian ve ark., 2008;Liu ve ark., 2013;Choudhary ve Agraval, 2014;Zhang ve ark., 2014). Fiziksel uygulamaların bitkilere etkisi bitki türü, çeşidi, bitkinin gelişme safhası, uygulama şekli, uygulama dozu, uygulama süresi gibi çeşitli faktörlere bağlı olarak değişmektedir (De Micco ve ark., 2014). ...
Günümüzde bitki büyümesini teşvik etmek amacıyla çevre dostu alternatif fiziksel yöntemlere yönelik yoğun araştırmalar yapılmaktadır. Bu çalışma, fiziksel yöntemler arasında yer alan ultraviyole-C ve ultrason uygulamalarının dünyada ve ülkemizde en fazla yetiştiriciliği yapılan yazlık sebze türlerinden domates ve hıyarda fide gelişimi üzerine etkilerini belirlemek amacıyla yapılmıştır. Bitkisel materyal olarak Falcon ve H-2274 domates çeşitleri ile Prima ve Beith Alpha hıyar çeşitlerinin kullanıldığı çalışmada 1) Kontrol, 2) Ultraviyole-C (UV-C), 3) Ultrason (US) ve 4) UV-C+US uygulamaları ele alınmıştır. Çalışmada fide boyu, gövde çapı, kök uzunluğu, fide yaş ve kuru ağırlığı, yaprak sayısı ve klorofil miktarı belirlenmiştir. Araştırma sonucunda UV-C, US ve UV-C+US uygulamalarının kontrole göre fide büyüme parametreleri üzerine olumlu etkilerinin olduğu belirlenmiştir. UV-C+US uygulamasının araştırmada ele alınan 4 çeşitte de fide gelişimi üzerine daha etkili olduğu ve kontrol uygulaması ile karşılaştırıldığında, çeşitlere bağlı olarak fide boyu, fide yaş ağırlığı ve fide kuru ağırlığını sırasıyla %16.99-45.11, %24.82-39.88 ve %37.93-52.63 oranında artırdığı belirlenmiştir. Sonuç olarak, UV-C ve US uygulamaları ile her ikisinin kombinasyonunun domates ve hıyarda fide gelişimini artırmada alternatif bir uygulama yöntemi olarak kullanılabileceği tespit edilmiştir.
... Effective sterilization is a known effect of nitrogen-rich high-pressure plasmas, which has been attributed to the effect of UV radiation [42], likely through the rupture of the microbial genetic material [43]. It is known that energetic UV photons speed up the germination process due to the breakdown of seed coatings, although they have other associated effects such as retarded seedling growth and root damage [44,45]. However, under our working conditions, UV photons of low intensity are mainly associated with the weak emission lines due to the second positive system of activated N 2 * species ( figure 1) and, consequently, a substantial effect on germination can be discarded. ...
Plasma treatment is increasingly being explored as an effective presowing treatment improving seed germination. This study examines the synergetic effect of the irrigation condition and the physicochemical surface properties of wheat seeds subjected to atmospheric dielectric barrier discharge plasma activation on their water uptake and germination. Extensive surface analysis revealed a remarkably enhanced wettability of plasma‐treated seeds due to the insertion of oxygen‐containing functionalities on their surface. However, long plasma exposures damaged the outermost layers of the pericarp due to a pronounced oxidative etching effect. Although the seed germination capacity was not affected by the plasma treatments, short plasma exposures were shown to enhance water uptake and accelerate seed germination, especially under water‐scarcity conditions.
... In the last decades there was an increased apprehension regarding the negative impacts that environmental uncontrolled solar UV-B radiation may have on plants growth (Kakani et al., 2003). However, after the discovery of the role of UV signalling in plant cells, the scientific community is looking at UV-rays also as an opportunity to artificially modulate the seed/seedling performance, plant development, flowering, and fruit production (Hiramatsu et al., 2014;Huché-Thélier et al., 2016;Noble, 2002). Thus, a new paradigm in agro-food industry is emerging, regarding the benefits that moderate UV-supplementation may bring to improve crops nutritional value. ...
Solanum lycopersicum L. is among the healthiest fruits/vegetables due to its richness in bioactive compounds. However, its fruits from off-season (usually obtained in greenhouses that block UV-rays) have lower reputation than the ones of in-season/field productions. We hypothesise that moderate UV-A/UV-B irradiation during fruit development is able to improve its bioactive compounds and sensorial attributes, increasing its healthy properties. We supplemented for 30 days 'MicroTom' fruiting plants with two daily doses of UV-A (1 or 4 h) and UV-B (2 or 5 min). Irradiated plants showed higher ripening synchronization and produced more and smaller fruits. UV-A irradiation stimulated the fruit's antioxidant capacity, and the antiradical activity by the accumulation of phenolic compounds including the flavonoids. Only the UV-A1 h condition promoted the accumulation of ortho-diphenols in tomato fruits. Regarding the consumers' preference for aroma/taste, a consumers' panel test ranked the tomatoes as UV-A 1 h, UVA 4 h, Control, UV-B 5 min and UV-B 2 min. We conclude that the supplementation of UV-A during pre-harvest is particularly effective in increasing ripening synchronization and fruit's nutritional properties, potentially making these fruits more appealing to consumers.
... Additionally, the UV radiation emitted by the SDBD plasma source has to be taken into consideration since it was reported that UV irradiation can accelerate seed germination accompanied by a retarded seedlings growth (Noble, 2002). Decreased growth of sprouts may also be attributed to the presence of ozone. ...
... This is probably due to the fact that UV photons (<400nm) are more energetic than visible light photons (>400nm) and, hence have a stronger effect on the surface of the plant cell 11 . According to another report stronger effect of UV on plant surface cell causes the ultimate break down of seed coating allowing germination to occur 12 . The effect of UV-A (366 nm) and UV-C (254 nm) radiation on dry mass production and specific leaf area parameters was showed in (Fig. 1). ...
Twelve compounds have been isolated for the first time from Amberboa ramosa namely, octacosanoic acid (1), cinnamicacid (2), 7,8-dihydroxycoumarin (3), 5-hydroxy-7,8-dimethoxyflavone(4), 5-hydroxy-3,6,7,4-tetramethoxyflavone (5), 5,7,3',4'-tetrahydroxyflavone (6),-amyrin (7),-amyrin acetate (8), marrusidin A (9) marrusidin B (10), polyodonine (11), stigmasterol 3-O-b-D-glucopyranoside (12)respectively. Their structures have been elucidated by EI-MS, HR-EI-MS, HR-FAB-MS, 1H-NMR and 13C-NMR spectroscopic data. Compounds 2-6 showed moderate antioxidant activity.
... Some studies showed different effects of UV irradiation in germination of various kinds of seeds. Percentage germination of the redbean seeds was inversely related to the UV irradiation doses (Peykarestan and Seify 2012) while germination of kale, cabbage, radish and agave seeds was sped up due to UV irradiation (Noble 2002). ...
Concerns regarding the safety of transgenic foods have been raised because of possibility of undesirable effects development during genetic engineering. Analysis of phenotypic traits can increase the likelihoods of identifying those unintended effects in dietary composition of the GM crops. Objective of this study was to compare the transgenic lines with their non-transgenic counterpart. Different vegetative and reproductive traits as well as antioxidant properties were considered to evaluate the transgenic (HV8 and HV23) lines containing CaMsrB2 gene and their non-transgenic (Ilmi) parent line. Grain size and weight, seed germination, root length, root and shoot dry weight, length and width of flag leaf, plant height, and ligule, stamen and carpel length were not significantly different. Onset and completion of heading in each line occurred almost during the same period. The antioxidant properties in terms of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and polyphenol content were not statistically different under same treatment condition. The results suggested that the transgenic rice lines containing CaMsrB2 gene were equivalent to their non-transgenic counterpart without any visible unintended effects.
... However, the final germination percentage remained unaffected in a variety of red bean (Peykarestan and Seify, 2012). In contrast UV-irradiation speeded the germination of kale, cabbage, radish and agave seeds (Noble, 2002). Similarly, Shaukat et al., (2013) reported that UV-irradiation substantially increased the velocity of seed germination, however, the final germination percentage remained significantly suppressed by UV-irradiance. ...
In this study, caryopses of maize were exposed to UV-C radiation for 30, 60, 120 and 240 minutes before sowing to
determine the effects on seed germination, plant growth, leaf area and colonization of common root-infecting fungi such as
Fusarium species, Rhizoctonia solani Kühn. and Macrophomina phaseolina (Tassi) Goid. UV-C reduced seed germination,
shoot length, shoot weight, root length and leaf area and improved root weights after various times of exposure.
Colonization percentages of Fusarium species was reduced on 60 and 120 minutes of exposure of seeds. UV-C radiations
completely eliminated R. solani and M. phaseolina in roots of maize on 30-minutes-exposure. However, longer exposure
(240 minutes) increased their colonization percentages. It is concluded that seed treatment with UV-C radiations for 30 to
120 minutes effectively reduced incidence of commonly found root-infecting fungi.
... On the other hand, Wagne (1966) investigated the effect of UV light on lettuce seeds and noted improvement in germination (at 254-405 nm). Noble (2002) investigated the effect of UV-B irradiation on seeds of four species and found that germination was not affected. However, he showed that the speed of germination was increased which is consistent with the results of the present study. ...
The study focuses on the effect of supplemental UV-B radiation on germination, seedling growth, chlorophyll a and b contents, soluble phenols, anthocyanins, flavones contents, phenylalanine ammonia lyase (PAL) activity and tyrosine ammonia lyase (TAL) activity of mash-bean (Vigna mungo (L.) Hepper.). Even though the germination velocity was substantially increased, the final germination percentage remained significantly suppressed by UV-irradiance. Both root and shoot growth of the seedlings were markedly reduced by enhanced UV-B radiation. UV-B irradiation substantially decreased both chlorophylls a and b and the total amount of chlorophyll a plus b compared to controls. However, chlorophyll a/b ratio was generally elevated. Remarkable accumulation of total soluble phenols occurred in response to UV-B radiation. PAL activity increased markedly as a result of UV-stress in the beginning, subsequently, however, it declined, whereas, TAL activity consistently increased over the controls following UV-B irradiation up to 8 days of treatment. The levels of anthocyanins and flavones increased in treatments over the controls as they provide a protective mechanism to UV-B radiations. In general, the growth and physiological responses to UV-B radiation were more pronounced at greater exposure period.
Climate change is real and inevitable, incessantly threatening the terrestrial ecosystem and global food security. Although the impacts of climate change on crop yield and the environment have received much attention in recent years, there are few studies on its implications for the production of high-quality seeds that provide the basic input for food production. Seeds are the primary planting material for crop cultivation and carry most new agricultural technologies to the field. Climatic abnormalities occurring at harvest and during the post-harvest stages may not always severely impact seed yield but can reduce the morphological, physiological and biochemical quality, ultimately reducing the field performance and planting value of the seed lot. In our preliminary data mining that considered the first 30 species appearing in the search results, seed setting, seed yield and seed quality parameters under temperature, CO 2 and drought stresses showed differential response patterns depending on the cotyledon number (monocots vs. dicots), breeding system (self-vs. cross-pollinated), life cycle (annual vs. perennial) and maturity time (seed setting in cooler vs. hotter months). The relative proportions of the 30 species showed that germination and seedling vigour are adversely affected more in dicots and self-pollinated annual species that set seeds in hotter months. Together, these impacts can potentially reduce the quantity and quality of seeds produced. Immediate attention and action are required to understand and mitigate the detrimental impacts of climate change on the production and supply of high-quality seeds. This review summarises the current knowledge on this aspect, predicts the future implications and suggests some potential mitigation strategies in the context of projected population growth, climate change and seed requirement at the global level.
To investigate whether low-level lighting is necessary and which narrow-band light spectra are effective in seeds germination, seeds of 14 genotypes from begonia, echinacea, gerbera, petunia, and vinca were germinated under ultraviolet-B (UVB), blue (B), green (G), red (R), far-red (FR) light, or darkness. Light-emitting diode (LED) fixtures provided all spectrum treatments except for UVB, which was provided by a narrow-band fluorescent light. The photon flux density at seed level was ≈18 µmol m-2 s-1 for B, G, R, and FR, and 0.4 µmol m-2 s-1 for UVB. Based on daily germination observations, final germination percentage, germination onset time, germination time spread, and germination speed were compared among different spectrum treatments for each of the plant genotypes. There were no promotive effects on final germination percentage, germination onset time, and germination time spread under the narrow-band lights compared to darkness. For all plant genotypes, B had a similar effect as darkness on seed germination. FR inhibited seed germination relative to darkness by reducing final germination percentage by 31–88%, delaying germination onset time by 30–40%, and decreasing germination speed by 11–48% in some genotypes. Under R, G, and UVB compared to darkness, germination speed was promoted for begonia ‘Apricot Shade’, a light-requiring genotype, and inhibited for vinca ‘Burgundy’, a light-inhibited genotype. Therefore, lighting at low levels used in our study is unnecessary for seed germination of the tested species except light-requiring genotypes, where R, G, and UVB are the most promotive among the tested narrow-band lights.
Rose is one of the most important cut flowers all over the world as well as in Korea. Growers in Korea are exclusively relying on foreign cultivars. A rose breeding programme was started a decade ago in Korea. Lack of knowledge lead to a number of research topics for Korean researchers. One of these topics is the low germination rate in rose seeds which is in general about 20%. High amounts of substances that inhibit germination were found in the pericarp of the achene. Four different treatments such as scarification (0, 1, 5, and 10 min), UV-irradiation (0, 5, 10, 20, and 30 min), immersion in surphuric acid (0, 5, and 10 min) and microorganism (Klebsiella oxytoca C1036 treatment for 0, 1, and 48 h), were applied to improve germination rate. Only microorganism treatments (1 and 48 h) were successful in improving germination rate by two times compared to the control. Presently several other microorganisms are being tested.
Key message: Higher polyamine levels of fully developed embryos had positive effects on their ability to tolerate UV-B irradiation when compared with induced responses of early embryos. Abstract: The aim of this work was to test the hypothesis that the higher levels of polyamines (PAs) might be involved in the response of Norway spruce somatic embryos to UV-B irradiation. We compare here the effects of 0.1, 0.6 and 6 W m−2 h−1 UV-B irradiation on polyamine metabolism in early and fully developed Norway spruce somatic embryos. The impact of UV-B treatment on irradiated embryogenic suspensor mass (ESM, consisting of early somatic embryos) and matured somatic embryos was assessed by measuring changes in the content of PAs and the activities of enzymes involved in their biosynthesis. Under control conditions, developmental stages of embryos are characterized not only by clear differences in their histological structure, but also by the levels of free PAs, which are several fold higher in fully developed embryos than those of early embryos. The decrease in the PA content and the decline in PA biosynthetic enzyme activities in irradiated ESMs were dependent on the doses of UV-B irradiation applied and the length of time after the exposure. The viability of ESM and its histological structure changed depending on the dose applied. The effect was much more pronounced in ESM treated with higher UV-B doses (0.6 W m−2 h−1), where the embryos were seriously damaged or killed, and irradiation with 6 W m−2 h−1 was lethal to the culture. No marked differences in PA contents were observed between control and UV-B irradiated fully developed embryos. The effect of UV-B irradiation on fully developed embryos was marginal when compared with that on proliferating tissue. The increase in malondialdehyde (MDA) levels in irradiated ESM was correlated with the decrease in their PA contents. Neither significant increases in MDA levels nor significant changes in PA content were observed in the fully developed embryos after irradiation; this may indicate that the plants’ defence mechanisms are particularly active in these tissues. The accumulation of higher levels of PAs in fully developed somatic embryos may be causally linked to their better tolerance to UV-B irradiation.
Ultraviolet radiation is energetically capable of disrupting proteins. Ultraviolet radiations Are divided into three bands included UV-A (320-390 nm), UV-B (280-320 nm) and UV-C(254-280nm). Several studies have indicated that enhanced UV-B radiation can deleteriously affect physiological processes and overall growth in some plants species.Bean Sayad and Bean Derakhshan seeds irradiated with 220 to 400 nm UV rays were grown in incubator for 8 days at 25±°C. Germination, growth (seedling fresh weight, root shoot length and their ratio), lipid peroxidation, protease and peroxidase activity were measured in leaves. Results showed that percent germination of the seeds and the rates of growth of sprouts were inversely related to the irradiation doses. In Derakhshan, peroxidase and protease activities (two folds) and MDA contents were higher as compared to Bean Sayad while vice versa for protein contents, revealing inherent differences between two types. Data for protein contents,peroxidase and protease activities therefore suggested that irradiation dose should not under 300nm UV in Bean Derakhshan and also 300nm UV in Bean Sayad. In Bean Derakhshan 320 to 400 nm UV irradiation dose non-significantly affected the protein contents and peroxidase activity and uppered MDA contents and protease activity. In Bean Sayad 300 nm UV irradiation dose increased the peroxidase activity,uppered the MDA contents and affect the protein content and protease activity. It was concluded that protein contents, protease, peroxidase and lipid peroxidation may be used in early assessment of effectiveness and superiority of radiation dose to induce mutations.
Seed germination response of black nightshade to hormones, osmotic potential, salt stress, pH and burial depth was investigated in laboratory and green house. Adding the concen-tration of GA 3 increased seed germination to 99% at the treatments of 25, 200 and 400 ppm. Seed germination decreased as concentration of cytokinin increased from 0.1–5 mM. Wet and dry prechilling duration increased seed germination of black nightshade. Germination of black nightshade seeds decreased as ethanol concentrations increased from 0.3 to 30%. A significant decline in germination was observed by increasing in NaCl concentration. Germination of black nightshade seed significantly decreased as the osmotic potential de-clined. Seed germination was observed over a broad range of pH. Seedling emergence was the greatest for seeds scattered on the soil surface and decreased by increasing in planting depth.
Ultraviolet irradiation is energetically capable of disrupting proteins. Ultraviolet radiations are divided into three bands included UV-A (320-390 nm), UV-B (280-320 nm) and UV-C (254-280nm). Several studies have indicated that enhanced UV-B radiation can deleteriously affect physiological processes and overall growth in some plants species.Purslane and Thyme seeds irradiated with 220 to 400 nm UV rays were grown in incubator for 8 days at 25±°C. Germination, growth (seedling fresh weight, root shoot length and their ratio), lipid peroxidation, protease and peroxidase activity were measured in leaves. Results showed that percent germination of the seeds and the rates of growth of sprouts were inversely related to the irradiation doses. In Thyme, peroxidase and protease activities (two folds) and MDA contents were higher as compared to Purslane while vice versa for protein contents, revealing inherent differences between two types. Data for protein contents,peroxidase and protease activities therefore suggested that irradiation dose should not under 300nm UV in Thyme and also 300nm UV in Purslane. In Thyme 320 to 400 nm UV irradiation dose non-significantly affected the protein contents and peroxidase activity and uppered MDA contents and protease activity. In Purslane 300 nm UV irradiation dose increased the peroxidase activity,uppered the MDA contents and affect the protein content and protease activity. It was concluded that protein contents, protease, peroxidase and lipid peroxidation may be used in early assessment of effectiveness and superiority of radiation dose to induce mutations.
High-value broccoli (Brassica oleracea var. italica L.) plant nutrition and water relations are not well understood. Our objectives were to examine the relations of plant nitrogen (N) and phosphorus (P) translocation and water holding in direct-seeded broccoli (cv. Everest) under different postseeding N treatments at field scale and with different growth media types and water supply levels under greenhouse conditions. A 2-year field study was conducted in a moderately drained Woodville loam in 2007 and in a poorly drained Lawrence loam in 2008. The field experimental treatments were the postseeding N rates of 0, 25, 50, 75, and 100 kg·ha−1, arranged with four blocks in a randomized complete block design. The greenhouse study treatments consisted of two growth media types, mineral soil (MS) and peat-based Promix (PP), and two water supply levels, 15% (W15) and 30% (W30), of the growth media weights, arranged with eight replicates in a completely randomized design. Results showed that the main effect of the postseeding N treatments was significant on broccoli head size (P < 0.0167). Block effects and the N treatment linear effects were significant on leaf/stem N and head N/P accumulation, broccoli yield, and head size (P < 0.05). Broccoli yield and head size were correlated with whole plant water holding, leaf/stem N, and head N/P accumulation (P < 0.05). In the greenhouse, broccoli leaf N/P accumulation, leaf chlorophyll, and whole plant biomass were significantly higher in the MS than in the PP (P < 0.0182). The interaction between growth media and water supply was significant on leaf P% and leaf N accumulation (P < 0.0027). It is suggested that mineral soil growth media, water supply at half field capacity (W15), and postseeding N inputs are important factors for promoting plant water holding and N/P translocation within plants to improve broccoli head development, and its sink/source relations.
Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.
Survival was measured as a function of the dose of germicidal UV light for the bacteria Escherichia coli, Salmonella typhi, Shigella sonnei, Streptococcus faecalis, Staphylococcus aureus, and Bacillus subtilis spores, the enteric viruses poliovirus type 1 and simian rotavirus SA11, the cysts of the protozoan Acanthamoeba castellanii, as well as for total coliforms and standard plate count microorganisms from secondary effluent. The doses of UV light necessary for a 99.9% inactivation of the cultured vegetative bacteria, total coliforms, and standard plate count microorganisms were comparable. However, the viruses, the bacterial spores, and the amoebic cysts required about 3 to 4 times, 9 times, and 15 times, respectively, the dose required for E. coli. These ratios covered a narrower relative dose range than that previously reported for chlorine disinfection of E. coli, viruses, spores, and cysts.
We examined the influence of solar ultraviolet-B radiation (UV-B; 280-315 nm) on the performance of Antarctic vascular plants (Colobanthus quitensis and Deschampsia antarctica) by placing filters that either absorbed or transmitted most solar UV-B over tundra along the Antarctic Peninsula for four consecutive growing seasons. The difference in biologically effective UV-B levels between our treatments was 65%, which was similar to the enhancement in ambient UV-B levels that appeared attributable to ozone depletion during the first 2 months of the growing season (November and December) at our site (62%). In both species, exposure to UV-B reduced vegetative growth, primarily through slower leaf elongation rates that led to shorter fully expanded leaves. In C. quitensis, exposure to UV-B also led to reductions in leaf longevity, branch production, cushion diameter growth, aboveground biomass, and thickness of the non-green cushion base and litter layer. Exposure to UV-B accelerated the development of reproductive structures and increased the number of panicles (D. antarctica) and capsules (C. quitensis) that reached maturity per unit of ground surface area covered by mother plants. However, this effect was offset by a tendency for these panicles and capsules to produce fewer spikelets and seeds. Ultimately, UV-B exposure did not effect the numbers of spikelets or seeds produced per unit of ground surface area. While seeds from plants exposed to UV-B tended to be lighter, germination rates were similar between UV-B treatments. The relative reductions in leaf elongation rates in D. antarctica attributable to UV-B exposure increased from the first (23%) through the fourth (43%) growing season, and relative reductions in leaf longevity in C. quitensis tended to increase from the first (9%) through the fourth (19%) growing season, suggesting that UV-B growth responses tended to be cumulative over successive years.
To develop a model system of herpes simplex labialis which would enable the study of patients before lesion onset, five patients were exposed to various doses of UV light from a sunlamp at their usual site of lesions. Six of 10 treatments resulted in the development of herpes labialis. Three of four treatments with the highest exposure levels led to large, vesicular, virus culture-positive sores. Side effects from sunlamp exposure were minimal.
The effect on the skin of exposure to relatively small doses of ultraviolet light has long been thought beneficial and socially desirable, leading to a 'healthy tan'. However it is less well known that similar (if not smaller) doses of UV-B radiation can have transient but profound depressive effects on the immune response to antigens or pathogens encountered by the skin. The result of this on the immunopathology of both primary and recurrent episodes of persistent viral infections of the epidermis is discussed.
Cataract prevalence increases with age. As the world's population ages, cataract-induced visual dysfunction and blindness is on the increase. This is a significant global problem. The challenges are to prevent or delay cataract formation, and treat that which does occur. Genetic and environmental factors contribute to cataract formation. However, reducing ocular exposure to UV-B radiation and stopping smoking are the only interventions that can reduce factors that affect the risk of cataract. The cure for cataract is surgery, but this is not equally available to all, and the surgery which is available does not produce equal outcomes. Readily available surgical services capable of delivering good vision rehabilitation must be acceptable and accessible to all in need, no matter what their circumstances. To establish and sustain these services requires comprehensive strategies that go beyond a narrow focus on surgical technique. There must be changes in government priorities, population education, and an integrated approach to surgical and management training. This approach must include supply of start-up capital equipment, establishment of surgical audit, resupply of consumables, and cost-recovery mechanisms. Considerable innovation is required. Nowhere is this more evident than in the pursuit of secure funding for ongoing services.
In response to an alarming increase in skin cancer rates, much work is being done to find causes, identify populations at risk, and appropriately modify behaviors and protective strategies. The causes of nonmelanoma and melanoma skin cancers are multifactorial; however, the evidence implicating ultraviolet radiation as a major factor is mounting. Sunlight consists of four important wavelengths. Two of them, UVA and UVB, are the most harmful because they cause direct cellular trauma and immunologic suppression. Sunburn is a delayed prostaglandin-mediated erythema that implies severe damage to DNA in a cumulative fashion. Avoidance recommendations include activity planning strategies, apparel choices, and sunscreen use. Clothing is generally protective and hats should cover highly exposed areas. Special apparel products incorporate UV protection into the fabric and offer an additional strategy for workers and enthusiasts who frequently venture into the outdoors. A sunscreen is a topical agent that provides protection against UV radiation. Specifics of sunscreen classification and labeling by the Food and Drug Administration are covered in this article, along with selection and application strategies for outdoor adventurers and travelers. Whereas ultraviolet radiation avoidance and sunscreen use are vital, public education will remain the cornerstone of an effective plan to reduce skin cancer rates.
The biological effect of gamma-rays is based on the interaction with atoms or molecules in the cell, particularly water, to produce free radicals, which can damage different important compounds of plant cell. The UV-B/C photons have enough energy to destroy chemical bounds, causing a photochemical reaction. The biological effect is due to these processes. This paper is focused on the structural and biochemical changes of the cell wall and plastids after gamma and/or UV-B irradiation. Gamma-rays accelerate the softening of fruits, causing the breakdown of middle lamella in cell wall. They also influence the plastid development and function, such as starch-sugar interconversion. The penetration of UV-B light into the cell is limited, while gamma-rays penetrate through the cells. For this reason, UV-B light has a strong effect on surface or near-to-surface area in plant cells. UV-B radiation influences plastid structure (mostly thylakoid membranes) and photosynthesis. Some kinds of pigments, such as carotenoids, flavonoids save plant cells against UV-B and gamma irradiation. Plant cells are generally ozone sensitive. The detoxifying systems operate at the cellular level. Methods for studying structural changes in plant cells develop in direction to molecular biology, combined with immunoassays and new microscopical techniques. Nowadays, UV-B radiation is undergoing much research, being an environmental factor which causes damage to both humans and plant cells.
Recent measurements of ozone levels have led to concern that the stratospheric ozone layer is being depleted as a result of contamination with man-made chlorofluorocarbons. Concomitantly, the amounts of solar UV-B radiation reaching the Earth's surface is increasing. UV-B radiation has been shown to be harmful to living organisms, damaging DNA, proteins, lipids and membranes. Plants, which use sunlight for photosynthesis and are unable to avoid exposure to enhanced levels of UV-B radiation, are at risk. Thus, mechanisms by which plants may protect themselves from UV radiation are of particular interest. This review will summarizes the main aspects of ultraviolet radiation on plants at physiological and biochemical level, with particular emphasis on protective structures and mechanisms.