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
mehdi panahyankivi; Abazar Abbasi; mahnaz mohamadzadeh nasrabadi
Abstract
Objective: The aim of this research is to investigate the effect of salicylic acid (SA) and brassinosteroid on yield and essential oil of coriander under water limitation conditions.
Methods: A field experiment was conducted as a split-plot on the basis of RCB design with three replications in two agricultural ...
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Objective: The aim of this research is to investigate the effect of salicylic acid (SA) and brassinosteroid on yield and essential oil of coriander under water limitation conditions.
Methods: A field experiment was conducted as a split-plot on the basis of RCB design with three replications in two agricultural seasons of 2020 and 2021. Irrigation intervals (irrigation according to 70 (control), 100, 130 and 160 mm evaporation from class A pan) were assigned to the main-plots and foliar application treatments (control, SA (1 mmol) and brassinosteroid (1 μmol) were allocated to the sub-plots.
Results: The results demonstrated that the application of SA and brassinosteroid significantly increased the relative water content, the membrane stability index, and the leaf area index. SA and brassinosteroid treatments increased the number of umbels per plant (14.1 and 7.3 percent), biological (21.9 and 10.2 percent) and grain (18.6 and 9.6 percent) yield. Essential oil yield increased by 23.5 and 11.9 percent with SA and brassinosteroid, respectively. The highest water use efficiency (WUE) of grain and biological yields (0.62 and 3.95 kg/m3) was obtained from the SA treatment under irrigation after 100 mm evaporation.
Conclusion: Treatment of plants with SA had a better effect compared to brassinosteroid on increasing grain yield and WUE. Therefore, under moderate and severe stress conditions (irrigation based on 130 and 160 millimeters of evaporation, respectively), the foliar application of salicylic acid can enhance the coriander's tolerance to drought stress.