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The application of superabsorbents to soils and seed coatings is a pre-sowing seed treatment method that is commonly used to improve early vigor and establish stability and uniformity under water deficit conditions. To evaluate the interaction of seed coating and superabsorbent on Calotropisprocera L. (milkweed) under water deficit conditions, a greenhouse experiment was conducted. The experiment was conducted with four coating material levels (non-coated seeds and seeds coated with peat moss, vermicompost, and canola residue), four growth medium levels (soil, sand + soil, soil + 2 g superabsorbent, and soil + 4 g superabsorbent), and three field capacity regimes (25, 50%, and 100%) in a completely randomized design factorial arrangement with four replications. Reducing the field capacity from 100 to 25% led to decreased growth (shoot and root dry weights and leaf area) and chlorophyll content. The activities of SOD, CAT, APX antioxidant enzymes, and proline increased under drought stress. The use of superabsorbent polymers in growth media enhanced growth indices and chlorophyll content and decreased the activity of antioxidant enzymes and proline under water deficit conditions. The highest chlorophyll and growth indices were observed when 4 g of superabsorbent was added to the growth medium under drought stress. The application of 4 g of superabsorbent to the growth medium reduced the activity of antioxidant enzymes and proline. The use of seed coatings improved the growth indices, antioxidant enzyme activity, and chlorophyll content under drought stress. The most adaptive morphological and physiological responses to water stress were observed in the vermicompost-coated seeds. The vermicompost coating containing a superabsorbent polymer (4 g/kg soil) proved to be the best for establishing milkweed under mild (50% FC) and severe water deficits (25% FC). [ABSTRACT FROM AUTHOR]

Primary Trans Chromosomal Tritipyrum (PTCT) amphiploid is a new cereal grown in saline soil and brackish water for grain and forage production. We evaluated the tolerance to seed deterioration in 13 promising PTCT lines, assessing accelerated aging (AA) tests by using AA boxes with 100% relative humidity at 40 °C for 72 h. The (Ma/b)(Cr/b)F4 and (St/b)(Cr/b)F4) PTCT lines, more sensitive to seed aging, were primed with NaCl, Salicylic Acid (SA), and Polyethylene Glycol (PEG) to increase the seed vigor of artificially aged seeds. Germination and emergence traits, biochemical parameters, and chromosomal abnormalities induced by artificial aging were measured in deteriorated and not-deteriorated seeds. The highest reduction percentages related to seed vigor were observed in (Ka/b)(Cr/b)F2 (34.52) and La(4B,4D)/b (28.15) lines, while the lowest was found in (Ma/b)(Cr/b)F4 (7.65) and (St/b)(Cr/b)F4 (7.46) lines. Seed aging also increases electrolytes, potassium, and protein leakages. Chromosomal abnormalities are caused by seed aging that interferes with chromosome behaviors during cell division. Seed priming on aged seeds revealed an increase in the germination percentage (GP) with PEG treatment, while the priming by SA showed an increase in seedling traits, such as the seedling length (SL2). In conclusion, we highlighted the potential use of different PTCT lines and the effective use of seed priming on deteriorated seed to enhance seed viability and seedling vigor as a useful tool for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Early growth water stress reduces the extract and fresh oil of Silybum marianum L. (S. marianum) shoots. Two experiments were conducted to reduce the effects of early growth drought. Treatments in the first experiment were organic seed cover fillers at three levels (control, vermicompost, and peat moss), hydrogel at seven levels (control, 2, 4, and 6 g hydrogelF1 per kg OSC, and 2, 4, and 6 g hydrogelA200 per kg organic seed cover), and water deficit at three levels (100, 50, and 25% of field capacity), and in the second experiment, seeds were inoculated with bacteria at four levels (control, Pseudomonas fluorescens, Pseudomonas putida, and their combination) and water deficit at four levels (100, 50, and 25% of field capacity). Our results showed that milk thistle seeds are sensitive to water deficit at the emergence stage. Covering milk thistle (S. marianum) seeds with organic seed cover increased water retention around the seeds and improved emergence percentage. Use of organic seed cover with hydrogel increased relative water content (RWC), leaf area, and shoot length, and increased extracts and oils in fresh shoots. Bacterial inoculation also improved initial growth and reduced the effect of water stress on the plant, and increased leaf number, extract, and oil. The combination of bacteria had a positive effect on initial growth and inoculation of seeds, P. fluorescens and P. putida increased relative water content (RWC), shoot height, and specific leaf area, and increased extract and oil under water deficit conditions. A comparison of the results showed that seed inoculation is a simple method without new culture medium, and improves extract and oil under water deficit conditions. [ABSTRACT FROM AUTHOR]

Plant growth regulators play an important role in control of seed germination. This experiment was conducted to investigate the effect of lant growth regulators (indole-3-acetic acid, gibberellin and kinetin) on seed germination of Hordeum spontaneum. Seeds of wild barley were soaked in distilled water (control) or different concentrations of gibberellin (25, 50, 75, 100, 125 and 150 mg L-1), indole-3-acetic acid and kinetin (5, 10, 15, 20, 25 and 30 mg L-1). The following germination parameters were determined: germination percentage, germination index, mean germination time, germination energy, germination value, seedling length and seed vigour index. The results showed that plant growth regulators, depending on the used concentration, effectively improved all germination parameters except the mean rate of germination, which was increased only by indole-3-acetic acid at concentrations of 20 and 25 mg L-1. Gibberellin was generally shown to be more effective on all evaluated traits except the mean rate of germination. The highest values in germination percentage, germination index, germination energy, germination value, seed vigor index were obtained by using gibberellin at 75 mg L-1 and followed by 100 mg L-1. Gibberellin also at concentration of 50 and 125 mg L-1 led to the greatest mean germination time and seedling length, respectively. [ABSTRACT FROM AUTHOR]