Shoots Of Seedlings Research Articles

Bacillus Strains with Catalase Enzyme Improve the Physiology and Growth of Rice (Oryza sativa L.)

Catalase can decompose hydrogen peroxide in plants under controlled and stressed conditions. In a stressed environment, an increase in hydrogen peroxide production makes catalase activity a major defense system for plant growth. The current study was conducted to evaluate the catalase activity of the pre-isolated and identified bacterial strains Bacillus aryabhattai (AN30), Bacillus megaterium (AN24), Bacillus megaterium (AN31) and Bacillus megaterium (AN35) and their potential for rice seedling growth promotion. These strains were characterized for quantitative catalase, urease, siderophore and exopolysaccharide production using LB media. Subsequently, the effectiveness of these strains was checked by quantifying the catalase activity in the rhizosphere, roots and shoots of rice seedlings. The secretion of organic and phenolic compounds produced by the tested strains in liquid culture was also investigated. Plant growth parameters were also studied in a growth room trial. Our results showed that the strain AN24 showed the maximum catalase activity (1.36 mol cm−1), urease activity (1.35 mol cm−1) and exopolysaccharide (4.20 µg mL−1) and siderophore (2.32%) production in LB media. All tested strains showed significantly higher catalase activity in soil compared to the control. Among sole applications, strain AN24 showed better results; however, the consortium application of strains AN24 + AN30 + AN35 + AN31 showed the maximum improvement in dry biomass, shoot and root length, and increase in catalase activity of rice seedlings. The results showed that a consortium of these Bacillus strains with catalase activity has greater potential to enhance the antioxidant defense system and growth promotion of rice seedlings. However, further experimentation under natural conditions is required before using these strains as potential bioinoculants for improving rice growth and yield.

Mechanisms involved in the sequestration and resistance of cadmium for a plant-associated Pseudomonas strain

Understanding Cd-resistant bacterial cadmium (Cd) resistance systems is crucial for improving microremediation in Cd-contaminated environments. However, these mechanisms are not fully understood in plant-associated bacteria. In the present study, we investigated the mechanisms underlying Cd sequestration and resistance in the strain AN-B15. These results showed that extracellular Cd sequestration by complexation in strain AN-B15 was primarily responsible for the removal of Cd from the solution. Transcriptome analyses have shown that the mechanisms of Cd resistance at the transcriptional level involve collaborative processes involving multiple metabolic pathways. The AN-B15 strain upregulated the expression of genes related to exopolymeric substance synthesis, metal transport, Fe-S cluster biogenesis, iron recruitment, reactive oxygen species oxidative stress defense, and DNA and protein repair to resist Cd-induced stress. Furthermore, inoculation with AN-B15 alleviated Cd-induced toxicity and reduced Cd uptake in the shoots of wheat seedlings, indicating its potential for remediation. Overall, the results improve our understanding of the mechanisms involved in Cd resistance in bacteria and thus have important implications for improving microremediation.

Influence of Charcoal, Manure and Fertilizer Soil Amendment on Growth of Grevillea robusta Nursery Seedlings

Soil amendment is vital especially in tree nurseries that are located away from the forest areas. Grevillea robusta seedlings are high nutrient demanders. An experiment was set up for a period of 8 months in 2021 at Egerton University, Njoro, Kenya to determine the effect of soil amendment on the early growth of Grevillea nursery seedlings. The experimental design was a CRD with 12 treatments replicated 3 times. The soil amendments included; manure, charcoal and artificial fertilizer combined with agricultural soil as well as their other combinations while forest soil was used as a check. The pot size was 9 by 12 cm in width and length respectively. Routine weeding and watering was done during the experimental period. The data was analyzed using SAS statistical package and the significance differences between means were separated using LSD at P<0.05. The results showed that forest soil and agricultural soil gave significantly (P < 0.05) the highest survival (84 and 81%) respectively compared with charcoal + manure + fertilizer combination (37%) which was the least. On the other hand, Forest soil had significantly (P < 0.05) the highest height (14.6cm) compared to all the other variables. Similarly, forest soil showed the highest root collar diameter (4.5 mm) which was significantly different from all the other variables measured except agricultural soil alone, agricultural soil + manure + fertilizer and agricultural soil + charcoal + manure which were similar. On the other hand, charcoal alone showed the highest root: shoot ratio (3.2), as well as root biomass which were significantly (P < 0.05) higher compared with agricultural soil + manure and charcoal + fertilizer. In conclusion, forest soil was superior in supporting the growth of both shoot, foliage and root collar diameter of grevillea seedlings. On the other hand, charcoal showed higher root to shoot ratio as well as root biomass. Forest soil is therefore recommended to be used in raising Grevillea nursery seedlings in areas nearby the forest. However, for areas located far away from the forest, a mixture of agricultural soil + manure + fertilizer or charcoal is recommended. Further research is recommended on using the same soil mixtures on other tree species which are less demanding in nutrient uptake.

Keadaan bahan kering bibit kelapa sawit dengan aplikasi kompos tankos dan Bacillus sp.

Organic fertilizer in the form of compost is possible to be continuesly applied in oil palm plantations, including in nurseries. This is one of the efforts to support the realization of sustainable oil palm plantations. This experiment aims to examine the effect of adding compost made out of empty oil palm bunches (EOPB) and bacteria Bacillus sp. applied either singly or in combination between the two to the state of the dry matter of oil palm seedlings. The experiment was carried out at the Ciparanje Experimental Garden, Faculty of Agriculture, Padjadjaran University from February to May 2022. The experiment was a field test using a randomized block design consisting of nine treatments, repeated three times. The treatments included NPK inorganic fertilizer, Bacillus sp. (25 mL and 35 mL), EOPB compost (100 g, 150 g and 200 g) given to each oil palm seedlings. The experimental results showed that the administration of Bacillus sp. 25 mL/seedling alone had good effect on the dry weight of the roots and dry weight of the oil palm seedlings, while the addition of 150 g/seedling EOPB compost alone had a good effect on the dry weight of the oil palm seedling shoots. The condition of the dry matter of the seedlings with the provision of Bacillus sp. and EOPB compost is as good as oil palm seedlings which are only given NPK fertilizer so that in this case the EOPB compost and Bacillus sp. can be used as an alternative fertilizer to be applied in oil palm nurseries.

Seed nano-priming using silica nanoparticles: effects in seed germination and physiological properties of Stevia Rebaudiana Bertoni

BackgroundThis study aimed to assess the effects of different concentrations of silicon (Si) nutrient sources, including bulk silicon dioxide (bSiO2) and two types of silica nanoparticles, nSiO2 (I) and nSiO2 (II) at different concentrations of 1, 5, 10, 25, 50, and 100 ppm in the germination process of stevia. The priming experiment was conducted using a completely randomized design with three replicates to ensure the reliability of the results.ResultsAll stevia seedlings subjected to nano-priming significantly improved the germination parameters. The germination percentage increased by 106%, reaching 68% in nano-primed seedlings. Similarly, the germination rate showed a remarkable increase of 128.12% at 7.3 day−1. Additionally, the root, shoot, and seedling dry weight increased by 283%, 168.9%, and 220% and determined 0.092, 0.078, and 0.17 g plant−1, respectively, compared to the control. Furthermore, seed priming with nSiO2 (I) at a concentration of 10 ppm resulted in an increased catalase (CAT) activity (36.15 Umg−1 protein) and peroxidase (POX) activity (approximately 0.057 U.mg−1 protein). Also, the highest sucrose amount was observed in the root (equal to 160.4 μg g−1 DW) and shoot (equal to 247 μg g−1 DW) of seedlings primed with 10 ppm of nSiO2 (I). However, it should be noted that nano-priming at the highest concentration led to oxidative damage indicated by an increase in H2O2 concentration. Conversely, bSiO2 demonstrated a lesser effect on improving germination, seedling growth, antioxidant activities, and biochemical attributes compared to nSiO2 (I), and nSiO2 (II).ConclusionsThis study established that seed priming with nSiO2 (I) at a concentration of 10 ppm was the most effective in enhancing germination percentage and rate, root/shoot/dry weight, biochemical attributes, and enzyme activities (such as α-amylase, CAT, and POX). The results suggested that seed priming with nSiO2 (I) at the optimal concentration could improve the seed germination by enhancing the antioxidant system, starch metabolism, and ultimately protecting plants from oxidative damage.Graphical

Ameliorative Role of Boron on Morpho-physiological Characters of Mandarin Orange Seedlings under Aluminium Stress Condition

Darjeeling mandarin orange is well known for its unique and delicious taste. It is also considered as one of the major cash crop of Darjeeling hills. But in recent past, the production has been declined drastically due to some of the biotic and abiotic factors. Acidic soils are mainly confined in this region which has a complex interaction of growth limiting factors that can restricts growth by inducing stress on plants through triggering aluminium stress and micronutrient Deficiency. This has resulted in declination in production and quality of mandarin orange grown in foothills of Darjeeling. Since boron is known to act as ameliorative role under aluminium toxicity, the present study was investigated to understand the effect of boron in mandarin orange seedlings grown under aluminium stress condition. Seedlings of Darjeeling mandarin orange were fertilized with Hoagland solution containing four levels of boron (i.e, 0µM, 5µM, 10µM and 25µM H3BO3) and two level of Aluminium (i.e., 0µM and 1200µM AlCl3.6 H2O) up to 22 weeks. Seedlings without boron and aluminium was treated as the control. Aluminium at higher concentration severely hinder physiological changes in terms of shoot length, leave numbers, leaf area, fresh shoot, root weight, chlorophyll content and carotenoid of mandarin seedlings. However, the application of boron improved the physiological attributes under higher concentration of aluminium. Furthermore, application of boron concentration at 10µM proved to be better treatment for mandarin seedlings grown under aluminium stress condition.

Increased Tolerance of Massion's pine to Multiple-Toxic-Metal Stress Mediated by Ectomycorrhizal Fungi.

Pinus massoniana (Massion's pine), a pioneer tree species, exhibits restoration potential in polluted mining areas. However, the physiological and molecular mechanisms of ectomycorrhizal (ECM) fungi in Massion's pine adaptability to multiple-toxic-metal stress are still unclear. Hence, Massion's pine seedlings inoculated with two strains of C. geophilum, which were screened and isolated from a polluted mine area, were cultivated in mine soil for 90 days to investigate the roles of EMF in mediating toxic metal tolerance in host plants. The results showed that compared with the non-inoculation control, C. geophilum (CG1 and CG2) significantly promoted the biomass, root morphology, element absorption, photosynthetic characteristics, antioxidant enzyme activities (CAT, POD, and SOD), and proline content of Massion's pine seedlings in mine soil. C. geophilum increased the concentrations of Cr, Cd, Pb, and Mn in the roots of Massion's pine seedlings, with CG1 significantly increasing the concentrations of Pb and Mn by 246% and 162% and CG2 significantly increasing the concentrations of Cr and Pb by 102% and 78%. In contrast, C. geophilum reduced the concentrations of Cr, Cd, Pb, and Mn in the shoots by 14%, 33%, 27%, and 14% on average, respectively. In addition, C. geophilum significantly reduced the transfer factor (TF) of Cr, Cd, Pb, and Mn by 32-58%, 17-26%, 68-75%, and 18-64%, respectively, and the bio-concentration factor (BF) of Cd by 39-71%. Comparative transcriptomic analysis demonstrated that the differently expressed genes (DEGs) were mainly encoding functions involved in "transmembrane transport", "ion transport", "oxidation reduction process", "oxidative phosphorylation", "carbon metabolism", "glycolysis/gluconeogenesis", "photosynthesis", and "biosynthesis of amino acids." These results indicate that C. geophilum is able to mitigate toxic metals stress by promoting nutrient uptake, photosynthesis, and plant growth, thereby modulating the antioxidant system to reduce oxidative stress and reducing the transport and enrichment of toxic metals from the root to the shoot of Massion's pine seedlings.

Effect of bioslurry effluent on seedling growth of swiss chard (Beta vulgaris L.)

Glasshouse experiments to evaluate the effect of bioslurry effluent on seedling growth of Swiss chard (Beta vulgaris L) were conducted in summer 2017 and winter 2018 at Dohne Agriculture Development Institute, Stutterheim, Eastern Cape, South Africa. Two cultivars of Swiss chard, Star 1801 and Fordhook giant, were planted in 200 cavity trays using a hygromix commercial growing medium incorporated with fertilizer treatments at different rates of bioslurry: no incorporation (control), 50% bioslurry, 100% bioslurry, 200% bioslurry and the recommended rate of 2:3:4 (30) NPK fertilizers. In the glasshouse the experiments were arranged in a randomized complete block design (RCBD) which was replicated three times. At four weeks after germination, ten (10) seedlings per treatment were destructively sampled randomly to determine the plant growth and biological mass parameters: i) Seedling height, shoot and root height; ii) Seedling mass; iii) Fresh shoot and fresh root mass as well as their dry mass; iv) Nutrient content of leaves. The results indicated that fertilization with 100%Bioslurry produced significantly taller seedlings and shoot height, while the shortest seedlings were obtained from the recommended inorganic fertilizer. Fertilization with 200%Bioslurry and the control treatment produced significantly higher biological yield compared to other treatments. The interaction between fertilizer treatments, cultivar and season indicated that summer season performed better compared to winter in seedling growth and development, and Fordhook giant fertilized with 100% and 200% bioslurry was superior compared to Star 1801. Fertilization with 50% bioslurry resulted in seedlings with higher sodium, while the seedlings grown in the control treatment showed higher copper content. The highest manganese was obtained from the seedlings fertilized with the inorganic fertilizer. It is therefore, concluded that fertilization with bioslurry at 100% and 200% bioslurry application rates enhanced the growth and quality of Swiss chard seedlings. Key words: Bioslurry effluent, seedling growth, Swiss chard, cultivars, biological yield

Effect of Endophytic Bacteria Bacillus subtilis on Seedling Growth and Root Lignification of Pisum sativum L. under Normal and Sodium Chloride Salt Conditions

The influence of endophytic bacteria Bacillus subtilis (strain 10-4) was studied on the parameters of growth and tolerance as well as the intensity of lignin deposition in the roots of Pisum sativum L. seedlings under conditions of sodium chloride salinity (1% NaCl). It was found that the impact of salinity reduced the germination energy, viability, length of the roots and shoots of seedlings, their wet and dry weight, and also increased the content of proline and the level of lipid peroxidation (LPO). Pretreatment with strain 10-4 had a stimulating effect on seedlings in normal conditions and a protective effect on salinity, which was reflected in the improvement of germination energy and seed viability, root length, and accumulation of their dry mass under saline conditions; however, in terms of shoot growth under stress, there was no significant difference from the control (nonbacterized) variants. At the same time, strain 10-4 promoted earlier formation of lateral roots as well as a decrease in stress-induced LPO and proline content in seedlings, which indicates that cells are protected from oxidative and osmotic damage under saline conditions. Priority data were obtained on the important role of endophytic B. subtilis strain 10-4 in the process of lignification and strengthening of the barrier properties of the cell walls of the roots, which contributes to the reduction of the toxic effect of sodium chloride salinity and the implementation of the protective effect of these bacteria on pea plants.

Sulfur levels regulate the absorption and utilization of selenite in rapeseed (Brassica napus)

Selenium (Se) is a necessary trace element that contributes to the health of humans and animals alike. Humans rely on the consumption of Se-rich plants to achieve adequate levels of the nutrient, but many crop-growing regions are unable to keep up with demand through conventional agriculture alone. Hydroponic cultivation with inorganic Se sources such as selenate or selenite represents a valid opportunity for biofortification in plants. This method is largely free from dependence on local Se resources, and the appropriate optimizations of hydroponic ingredients have previously demonstrated improved plant Se. However, effective strategies to improve the absorption and utilization efficiency of selenite at physiological levels remain scarce. In this study, we manipulated sulfate levels in a selenite-containing hydroponic solution and found that a decreased supply was able to elevate Se contents more than 6-fold in the shoots of rapeseed seedlings, but only had a slight effect in the roots. Additionally, this low sulfur environment increased the root-to-shoot Se translocation efficiency by more than 6 times. Our Se speciation analysis showed that a large proportion of the root-absorbed selenite was transformed into organic forms under a normal sulfate supply, and that selenate and SeMeCys represent the main Se species involved in root-to-shoot translocation. A reduction in sulfate supply was also found to induce the upregulation of genes related to selenate distribution and a key rate-limiting step for organic Se biosynthesis. These findings are consistent with the dramatically enhanced accumulation of SeMet and selenate in both roots and shoots. Taken together, our results demonstrate that the regulation of sulfur levels has a great potential for the improvement of the Se enrichment efficiency in economically valuable aboveground organs of selenite-treated plants.

Growth Promoting Potential of Phosphate Solubilizing Enterobacter Cloaca and Enterobacter Hormaechei on Maize and Cowpea Seedlings

Introduction: Phosphorus plays a range of functions in the proper growth and development of plants. Numerous microbial species, including bacteria, fungi, actinomycetes, and even algae have been found to play a crucial role in the solubilization of phosphate. This study was therefore aimed at exploring the growth-promoting potential of phosphate solubilizing Enterobacter species on maize and cowpea seedlings. Methods: Five strains that showed remarkable phosphate solubilization potential were used for the study. The bacterial isolates consist of three strains of Enterobacter cloaca and two strains of Enterobacter hormaechei. Growth promotion studies were carried out under laboratory conditions (in blotters) and green house (soil environment). In the blotter study, percent germination, germination index, germination time, germination rate, and vigor index were estimated, while shoot and root lengths, number of leaves, and wet weight were estimated in the greenhouse study. Results: In both seedlings, percent germination, germination index, and vigor index showed significantly higher values in seeds primed with the isolates than in the water-treated seeds (p≤ 0.05). Throughout the period of planting, the shoot and root lengths of the isolate-treated seedlings showed significantly higher values than the untreated control setups. This observation was irrespective of the maize and cowpea seedlings. In both seedlings, shoot and root lengths were directly proportional to days of growth. The bacterial strains showed significantly higher growth promoting potential on the seedlings. Conclusion: Therefore, the availability of these phosphate solubilizing microorganisms in the soil could enhance the growth of the seeds.

Uptake, accumulation and translocation of traditional and novel organophosphate esters by rice seedlings in the presence of micro(nano)-polystyrene plastics: Effects of concentration and size of particles

Micro(nano)plastics (MNPs) and organophosphate esters (OPEs) are becoming ubiquitous as emerging pollutants. To data, the effects of MNPs on the uptake, accumulation and translocation of OPEs by rice plant are still unclear, especially for novel OPE species. In this study, the impacts of polystyrene MNPs of different sizes and concentrations on the uptake of eight OPEs (six traditional organophosphate triesters and two novel discovered aryl organophosphate triesters) by rice seedlings were investigated in hydroponic exposure experiments. The results showed that OPEs accumulated in a concentration-dependent manner in both the roots and shoots of rice seedlings. The impacts of MNPs on uptake by rice seedlings were concentration- and size-dependent by influencing the transpiration rate or activities of antioxidant enzymes. Especially, significant effects were usually found in exposure group of medium-size and high-concentration MNPs. MNPs had more obvious effects on OPE species with lower logKow in roots, whereas, more obvious effects on OPE species with higher logKow in shoots were observed. There was a significantly positive linear relationship between logTF and logKow (p < 0.001), and a significantly negative linear relationship between logRCF and logKow (p < 0.001), indicating that OPEs with higher hydrophobicity seemed to be more liable to be absorbed from solutions to roots, but difficult to further translocate to shoots. Without novel OPEs (bis-(2-ethylhexyl)-phenyl phosphate and tris(2,4-di-tert-butylphenyl)phosphate), better fits for a linear model for logKow and logRCF (or logTF) were exhibited, indicating differences between novel and traditional OPEs. This work highlights that the presence of MNPs could altered the characteristics of uptake, translocation and accumulation of OPEs in rice seedlings, and provides an important evidence for comprehensive control strategy of new pollutants.

Silicate solubilizing and plant growth promoting bacteria interact with biogenic silica to impart heat stress tolerance in rice by modulating physiology and gene expression.

Heat stress caused due to increasing warming climate has become a severe threat to global food production including rice. Silicon plays a major role in improving growth and productivity of rice by aiding in alleviating heat stress in rice. Soil silicon is only sparingly available to the crops can be made available by silicate solubilizing and plant-growth-promoting bacteria that possess the capacity to solubilize insoluble silicates can increase the availability of soluble silicates in the soil. In addition, plant growth promoting bacteria are known to enhance the tolerance to abiotic stresses of plants, by affecting the biochemical and physiological characteristics of plants. The present study is intended to understand the role of beneficial bacteria viz. Rhizobium sp. IIRR N1 a silicate solublizer and Gluconacetobacter diazotrophicus, a plant growth promoting bacteria and their interaction with insoluble silicate sources on morpho-physiological and molecular attributes of rice (Oryza sativa L.) seedlings after exposure to heat stress in a controlled hydroponic system. Joint inoculation of silicates and both the bacteria increased silicon content in rice tissue, root and shoot biomass, significantly increased the antioxidant enzyme activities (viz. superoxidase dismutase, catalase and ascorbate peroxidase) compared to other treatments with sole application of either silicon or bacteria. The physiological traits (viz. chlorophyll content, relative water content) were also found to be significantly enhanced in presence of silicates and both the bacteria after exposure to heat stress conditions. Expression profiling of shoot and root tissues of rice seedlings revealed that seedlings grown in the presence of silicates and both the bacteria exhibited higher expression of heat shock proteins (HSPs viz., OsHsp90, OsHsp100 and 60 kDa chaperonin), hormone-related genes (OsIAA6) and silicon transporters (OsLsi1 and OsLsi2) as compared to seedlings treated with either silicates or with the bacteria alone. The results thus reveal the interactive effect of combined application of silicates along with bacteria Rhizobium sp. IIRR N1, G. diazotrophicus inoculation not only led to augmented silicon uptake by rice seedlings but also influenced the plant biomass and elicited higher expression of HSPs, hormone-related and silicon transporter genes leading to improved tolerance of seedling to heat stress.

Management of Crown and Root Rot Caused by Rhizoctonia solani in Acid Lime (Citrus aurantifolia) under Screen House Conditions in Kirtipur, Kathmandu

Crown and root rot disease was among the major problems in acid lime (Citrus aurantifolia) seedlings grown in the nursery of Warm Temperate Horticulture Centre, Kirtipur, Nepal. Samples of the diseased plants were investigated at the laboratory of Nepal Plant Disease and Agro Associates. Rhizoctonia solani, Fusarium solani and Alternaria citri were found associated with the disease samples. On pathogenicity testing R. solani showed symptoms like those of the infected seedlings. Hence, a pot experiment was conducted in a completely randomized design with four replications to manage the disease. Acid lime seedlings grown in sterilized soil and inoculum of R. solani prepared in potato dextrose agar (PDA) were used for the experiment. The treatments included carbendazim 50WP @ 1000 ppm, Trichoderma viride @ 2 ml/l water, Pseudomonas fluorescens @ 2 ml/l water, A-arya 009 (essential oil and organic acids) @ 1 ml/l water, and control (water) which were applied by soil drenching before 15 days of pathogen inoculation. Carbendazim at 100 and 200 ppm was also evaluated against R. solani by poison food technique on PDA. In the pot culture, the effect of treatments was significant on the growth of root and shoot of seedlings and both disease incidence and severity. Carbendazim had significantly least disease incidence (43.75%) and least disease severity (18.75%) among the treatments 45 days after inoculation with the pathogen. Also, the fungicide at 100 ppm gave complete inhibition of R. solani in PDA culture. Hence, carbendazim could be suggested for the management of the citrus crown and root rot caused by R. solani. However, further study is required to find out appropriate concentration of the fungicide for effective management of disease.

Compositions of Fungicides with Growth Regulators which Reduce the Retarding Effect of Crop Protectants

One of the reasons for the decrease in the yield of crops is the retardant effect of fungicides. In addition, many fungicides have a toxigenic effect on the mycelium of the fungus. The combination of a fungicide and a plant growth stimulant in a complex preparation can help to reduce the level of the negative effect of the pesticide. It is proposed to introduce individual growth regulators and their combination into the composition of the seed protectant in doses of 50, 100, 200 g/l. The length and the weight of the root and shoot of seedlings under the influence of the seed protectant were less than in the control, and the weight of the endosperm of grain was greater. Under the influence of the seed protectant and gibberellic acid, the length of the shoots corresponded to the control, but their weight was decreased. Indolylbutyric acid, added to the seed protectant, contributed to the effective consumption of spare substances of the endosperm of grain and root growth. Under the influence of the protectant and diphenylurea, the length and the weight of the shoot increased significantly in a balanced manner. The composition of the protectant and the named growth regulators in minimal doses affected the growth of the roots and shoots in the best way of all variants. Preference should be given to low doses of phytohormones and their combination.

How Can Biological and Chemical Silver Nanoparticles Positively Impact Physio-Chemical and Chloroplast Ultrastructural Characteristics of Vicia faba Seedlings?

Through interactions with plant cells, silver nanoparticles (AgNPs) with both biological and chemical origins can stimulate physiological and metabolic processes in plants. To ensure their safe application in the food chain, it is necessary to investigate their effects on plant systems. Therefore, the effects of chemical AgNPs (chem-AgNPs) and biologically synthesized AgNPs (bio-AgNPs) at different levels (i.e., 0, 10, and 50 ppm) on physiological and biochemical traits {i.e., root and shoot growth traits, photosynthetic pigments (Chl a, Chl b, carotenoids, and total pigments), soluble sugars, total carbohydrates, starch, H2O2, and antioxidant enzyme activities} of Vicia faba L. seedlings were investigated. AgNPs were biosynthesized from silver nitrate (AgNO3) by a green synthesis approach using Jatropha curcas seed extract. The synthesized AgNPs were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM), zeta potential, Fourier-transform infrared spectra (FT-IR), and X-ray diffraction (XRD). The results showed that bio-AgNPs at 10 ppm resulted in the highest growth, physiological, and biological traits of faba bean seedlings in comparison with those obtained from both AgNO3 and chem-AgNPs treatments. On the other hand, all AgNPs treatments adversely affected the chloroplast ultrastructure, however, fewer negative effects were obtained with the application of 10 ppm bio-AgNPs. In addition, the roots and shoots of seedlings contained the lowest Ag content under different treatments at 10 ppm AgNPs in comparison to the highest level of AgNPs (50 ppm), which indicates that additional studies should be incorporated to ensure safe use of lower concentrations of bio-AgNPs in seed priming. In conclusion, the application of biogenic nanoparticles at 10 ppm can be recommended to enhance plant growth and the productivity of strategic crops.

Features of winter pea seeds germination under the action of growth regulators

Physiological features of pea seed germination under treatment with exogenous growth regulators based on biologically active substances were studied. Purpose. To investigate the influence of complex growth and development stimulators containing phytohormones and their analogs, Biosil and Gulliver Stimul, on the peculiarities of the seed germination processes and formation of the winter pea seedlings of the Moroz NS variety. Methods. Laboratory, measuring, weighing, quantitative, statistical. Results. The influence of aqueous solutions of growth regulators Biosil and Gulliver Stimul on the germination processes of winter pea seeds was analyzed. During research, it was established that the use of growth regulators contributes to the faster exit of seeds from the state of rest, which is illustrated by the active dynamics of germination. Treatment of winter pea seeds with growth regulators leads to an increase in germination energy by 10-12% and laboratory germination by 6-8% compared to the control. It was noted that the indicators of seed germination were sufficiently high in all samples, including control. The soaking in growth regulators solutions contributes to the 10-16 mg bigger swelling of seeds than in the control; better utilization of reserve compounds, and 38- 50 mg seed weight loss during germination. Phytohormones which are part of the preparations induced an increase in the development of the vegetative organs of pea seedlings, which was expressed in a rapid increase in the length of the shoot and root in experimental variants. The growth of the linear dimensions of the aboveground and underground parts of the seedlings was accompanied by the increase in the mass of raw material. Conclusions. Application of the Biosil and Gulliver Stimul composite plant growth regulators affects the processes of germination and the initial stages of growth of winter pea plants. Treatment of winter pea seeds with these preparations helps to improve seed germination and increase germination energy. The linear dimensions and mass of the raw matter of the roots and shoots of pea seedlings enlarged due to the influence of growth regulators. The maximum length of the root and shoot was observed under the use of Gulliver Stimul preparation

Comparative analysis of microRNA expression profiles in shoot and root tissues of contrasting rice cultivars (Oryza sativa L.) with different salt stress tolerance.

Rice is the second-most important primary crop in the world and one of the most susceptible crops to salt stress. Soil salinization hinders seedling growth and decreases crop yield by inducing ionic and osmotic imbalances, photosynthesis disturbances, cell wall alterations, and gene expression inhibition. Plants have developed a range of defense mechanisms to adapt to salt stress. One of the most effective means is to make use of plant microRNAs (miRNAs) as post-transcriptional regulators to regulate the expression of developmental genes in order to mitigate the detrimental effects of salt stress. In this study, the miRNA sequencing data between two contrasting rice cultivars, salt-tolerant Doc Phung (DP) and salt-sensitive IR28 seedlings, were compared under control and salt stress (150 mM NaCl) conditions to determine the salt stress-responsive miRNAs. Comparative analysis of miRNA sequencing data detected a total of 69 differentially expressed miRNAs in response to salt stress treatment. Among them, 18 miRNAs from 13 gene families, MIR156, MIR164, MIR167, MIR168, MIR171, MIR396, MIR398, MIR1432, MIR1846, MIR1857, MIR1861, MIR3979, and MIR5508, were identified to be specifically and significantly expressed in the shoot and root tissues of DP seedlings. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses further revealed that these detected miRNAs regulate a range of essential biological and stress response processes, including gene transcription, osmotic homeostasis, root formation, ROS scavenger synthesis, and auxin and abscisic acid signaling pathways. Our findings provide more insight into the miRNA-mediated responsive mechanisms of rice under salt stress and should benefit the improvement of salt stress tolerance in rice.

VALORIZATION OF TOMATO PLANT WASTES AND OPTIMIZATION OF GROWTH CONDITIONS FOR INDOLE-3-ACETIC ACID PRODUCTION BY Streptomyces plicatus STRAIN PT2

This study focused on the production of the phytohormone indole-3-acetic acid (IAA) using tomato plant tissues as feedstock and on highlighting its growth promotion effect on tomato seedlings. Twelve actinobacterial strains were screened for IAA production under standard growth conditions and the strain Streptomyces plicatus PT2 was selected as a promising producer. The establishment of growth conditions to increase IAA production by S. plicatus PT2 was conducted using Plackett-Burman mathematical design with seven variables. The variables L-tryptophan quantity and tomato roots-extract rate were the two significant variables influencing IAA production. The most impacting variables were optimized using the surface methodology (RSM) formulated according to the Central Composite Design (CCD). The optimized broth supplemented with 4 mg L-1 of L-tryptophan and 25% of tomato roots-extract significantly improved the IAA production from 96.3 µg mL-1 within 120h to a maximum of 110.29 µg mL-1 within 96h. The in-planta application of the produced IAA and a chemical IAA showed a significant increase in the dry weight, the shoot and root lengths of tomato seedlings. This is the first study showing the production of IAA using Streptomyces plicatus strain PT2 by exploring tomato plant tissues and its plant-growth promotion efficacy compared to a chemical marketed one. These results support a reasonable approach for the valorization of abundant worldwide tomato plant wastes in the phytohormones production bioprocesses.

X-radiation of Lotus corniculatus L. seeds improves germination and initial seedling growth

Purpose Lotus corniculatus L. (bird’s foot trefoil, BFT) is a valuable perennial legume forage species due to its high nutritive value, persistence under grazing, and condensed tannin content that improves ruminant production and prevents bloating. However, it is less preferred by farmers compared with other perennial forage legumes such as alfalfa because of slow germination, slow establishment and low seedling vigor. This study was conducted to determine whether X-ray seed priming could improve these deficiencies. Materials and methods Seeds of L. corniculatus cv. ‘AC Langille’ were irradiated at 0, 100, and 300 Gy. Non-irradiated and irradiated seeds were sown on Murashige and Skoog/Gamborg medium under in vitro conditions and cultured for 21 days. Germination percentage, mean germination time (MGT), germination rate index, length of shoot and root, fresh and dry weight of shoot and root, dry matter ratios of shoot and root, water content of shoot and root, and seedling vigor index were measured. Results The results of this study demonstrated that X-ray seed priming significantly increased the germination percentage of L. corniculatus, increased the germination rate and thereby shortened the MGT, and improved seedling growth. However, X-ray pretreatment also decreased seedling shoot and root biomass. Conclusions In this study, it is reported for the first time that X-ray seed pretreatment has the potential to address important seedling establishment issues in L. corniculatus.