Parvaneh Hataminia; Nosratollah Abbasi; Mohammad Javad Zarea
Abstract
Objective: Given the challenges of water scarcity and the need for sustainable agricultural practices, this study was conducted to evaluate the impact of plant growth-promoting bacteria on the physiological traits of durum wheat at the research farm of Ilam University during the 2016-2017 growing season. ...
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Objective: Given the challenges of water scarcity and the need for sustainable agricultural practices, this study was conducted to evaluate the impact of plant growth-promoting bacteria on the physiological traits of durum wheat at the research farm of Ilam University during the 2016-2017 growing season. The experiment was carried out as a factorial based on a randomized complete block design with three replications.Methods: The factors comprised three levels of plant growth-promoting rhizobacteria (Azospirillum brasilense, Azotobacter chroococcum and non-inoculated), irrigation in two levels (supplementary irrigation and rainfed), and two durum wheat cultivars (Saji and Dehdasht).Results: Supplemental irrigation significantly increased chlorophyll b and total chlorophyll content by 13.47% and 15.45% compared to rainfed conditions, respectively. Azospirillum and Azotobacter increased carotenoid concentration by 27% and 18.66% compared to the control, respectively. Moreover, the carotenoid concentration in the Saji cultivar was 21.42% higher than in the Dehdasht cultivar. The lowest anthocyanin concentration was observed in both Saji and Dehdasht cultivars under irrigated conditions (0.0055 and 0.0042 mmol g-1 fresh weight, respectively) and without bacterial inoculation. The Dehdasht cultivar had the highest leaf area index (6) compared to the Saji cultivar. A 16.60% decrease in the relative water content of leaves was observed at the reproductive stage under rainfed conditions. Among the two cultivars, the Dehdasht cultivar had a higher relative water content (55.03%). The highest ion leakage was observed under rainfed conditions (85.99%). Azospirillum and Azotobacter bacteria reduced ion leakage by 19.47% and 17.80% compared to the control, respectively. Catalase activity increased under rainfed conditions. Catalase activity was 15% higher in the Dehdasht cultivar than in the Saji cultivar. Plant growth promoting bacteria increased leaf area index, total chlorophyll, chlorophyll a, chlorophyll b, and catalase activity. Seed inoculation with Azospirillum bacteria increased peroxidase activity, and among the two inoculated cultivars, the Dehdasht cultivar had higher enzyme activity (27.60 μmol g-1 fresh weight of leaf). The highest grain yield (2923 kg ha-1) of durum wheat cultivars was obtained under supplemental irrigation conditions and inoculation with plant growth promoting bacteria.Conclusion: The obtained results demonstrated the positive effect of growth promoting bacteria on common cultivars of the Ilam area under supplementary irrigation
fereshteh darabi; Nosratollah Abbasi; Mohammad Javad Zarea
Abstract
This paper aims at evaluating the effects of putrescine and 24-epibrasinolide on altering the activity of antioxidant enzymes to tolerate drought stress in basil. The plan has been implemented as factorial split plot layout based on a randomized complete block design with three replications in the cropping ...
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This paper aims at evaluating the effects of putrescine and 24-epibrasinolide on altering the activity of antioxidant enzymes to tolerate drought stress in basil. The plan has been implemented as factorial split plot layout based on a randomized complete block design with three replications in the cropping years 2017-2018 and 2018-2019 at the research farm of the Faculty of Agriculture, Ilam University. Experimental treatments include drought stress at three levels (40, 80, and 120 mm evaporation from Class A evaporation pan) as the main plots, putrescine foliar application at three levels (0, 0.5, and 2 (mM) and 24- Epibrassinolid foliar application at three levels (0, 0.5, and 2 μM) as subplots. Results show that the highest amount of proline in 120 mm occurs during the first year of the experiment and the use of putricin (2 mM) and 24-epibrasinolide (0.5 μM) also cause a further increase in proline. The highest amount of catalase has been observed in the 120 mm evaporation treatment and the application of 2 mM putrescine. The interaction of drought stress, putrescine, and 24-epiprasinolide also show that the highest levels of ascorbate peroxidase and superoxide dismutase belong to the treatment of 120 mM where the highest concentrations of putrescine (2 mM) and 24-epibrasinolide (2 μM) is observed. Under optimal irrigation conditions (40 mm), the combined application of lower concentrations of putrescine (0.5 mM) and epibrasinolide (0.5 μM) and under drought stress conditions (80 and 120 mm), higher concentrations of these two substances (2 mM putrescine and 2 μM epibrasinolide) increase the enzyme guaiacol peroxidase. Multiple interactions of year, drought stress, putrescine, and 24-epibrasinolide have had a significant effect on total flavonoids and essential oil percentage of basil. In both experimental years, application of 2 mM putrescine and 2 μM 24-epibrasinolide at all levels of drought stress 120 mm cause a further increase in these two traits which has been greater in the first year than the second one. Concomitant use of 2 mM putrescine and 2 μM epibracinolide due to increased proline synthesis and antioxidant enzymes is the best treatment to reduce the effects of drought stress in basil, indicating a synergistic relation between the two. The substance boosts the growth of basil, increasing the percentage of its essence.