Effect of a foliar-applied biostimulant mixture on winter wheat (Triticum aestivum) under drought stress conditions

Comprehensive evaluation of biostimulants on leaf-level physiology, water use efficiency, and tuber quality in potato (Solanum tuberosum L.) under drought stress

The pressing need for sustainable agriculture and food security has led to increased interest in biostimulants (BS) to mitigate abiotic stresses such as drought. This study provides a comprehensive evaluation of five commercial BS (Vesta, Humifirst, Acadian, SilicaPower, and Crop-Set) on leaf-level physiology, water use efficiency (WUE), tuber yield, and tuber quality in potato under drought stress. Drought stress was applied at the onset of tuber initiation (51 days after planting) and lasted for 7 days followed by a 4-day recovery period. Drought stress significantly decreased leaf relative water content, photosynthetic parameters, and flavonol index compared to non-drought. The yield and glucose content were 26% and 21% lower, and the sucrose content was 59% higher in the tubers of the drought-stressed plants than in non-drought-stressed. BS effects were generally limited and dependent on water conditions, with significant interactions observed for WUE parameters. Under drought conditions, Vesta and SilicaPower increased intrinsic WUE by 36% and 30%, respectively, while instantaneous WUE increased by 25% with both Vesta and Humifirst and by 33% with SilicaPower. Under non-drought conditions, Acadian led to a 42% increase in intrinsic WUE and a 60% increase in instantaneous WUE. However, these effects were not consistently accompanied by improvements in photosynthesis, biomass, or yield. Overall, this comprehensive assessment indicates that tested BS exert limited effects on potato plant biomass and tubers yield under drought stress, with their primary influence restricted to increased leaf-level WUE and changes in tuber composition rather than providing broad drought stress alleviation at whole plant level.

Heat stress indices of wheat (Triticum aestivum L.) varieties as affected by sowing dates and growth regulators under sub-tropical conditions of Jammu

A field experiment was conducted during the rabi season of 2022–23 at the Research Farm, Division of Agronomy, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, to evaluate the effect of sowing dates, wheat (Triticum aestivum L.) varieties and plant growth regulators (PGRs) on yield and heat stress indices under sub-tropical conditions. The study involved three sowing dates, two wheat varieties and three PGR treatments in a split-split plot design. Results showed that sowing on 25 November recorded the highest canopy temperature depression (CTD), while 15 December sowing achieved the highest yield stability index (YSI). The variety DBW 303, particularly when treated with paclobutrazol, performed best in mitigating heat stress and achieving higher yields. Late sowing increased heat stress intensity and susceptibility, especially for variety JAUW 672 and untreated plots. It is concluded that, under the sub-tropical conditions of Jammu, sowing DBW 303 on 25 November with paclobutrazol application can enhance productivity and reduce the negative effects of heat stress.

Effect of biopreparations on nitrogen assimilation in spring wheat (Triticum aestivum L.) under stressful growing conditions

The article presents studies on the effect of biopreparations on nitrogen assimilation in spring soft wheat plants grown under stressful conditions resulting from either water deficit or excess soil moisture. It is known that recent years have seen a tendency towards an increase in the area of arable land in the Russian Federation affected by droughts, as well as periodic flooding and waterlogging, which significantly damage agricultural production. In this regard, the search for strategies to mitigate the negative effects of stress responses induced by either water deficit or waterlogging is of great practical and environmental significance and remains highly relevant. The aim of the study was to investigate the effect of biopreparations on nitrogen assimilation in two different spring wheat varieties under simulated water supply stress conditions. Spring wheat plants of the varieties Zlata and Radmira were grown under controlled vegetation conditions using a modified soil culture technique. The soil used was typical light loamy urbanozem, collected from the field experimental station of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. An adaptive effect of biopreparations was established under water deficit conditions, influencing nitrogen uptake by plants and the extent of nitrogen assimilation in wheat grain, thereby enhancing the ability of spring soft wheat to withstand adverse environmental conditions. A positive effect of the studied preparations on nitrogen uptake and assimilation processes in spring soft wheat plants varieties Zlata and Radmira was revealed. The effectiveness of biopreparations under various water supply stress conditions depended on their chemical composition and application method. It was shown that the greatest adaptive capacity of biopreparations was manifested under drought conditions during the critical period of plant development in both wheat varieties. The application of biopreparations provided optimal conditions for nitrogen uptake by plants and enhanced nitrogen assimilation processes, thereby promoting adaptive responses in plants and increasing the ability of spring wheat to withstand adverse environmental conditions.

Bio-fertilizers ameliorate drought tolerance and physio-biochemical attributes of Moringa oleifera plants under different irrigation scheduling

Increased drought stress is anticipated to impact crop productivity adversely, mainly in Africa and Southeast Asia. Drought-tolerant plant growth-promoting rhizobacteria (PGPR) have emerged as a ray of hope as an effective bio-enhancer and sustainable strategy for agriculture under water-deficit and recovery conditions to reduce reliance on chemical fertilizers and improve soil fertility. Keeping this in view, a field experiment was conducted to check the effectiveness of commercial bio-fertilizers Phosphorine, Microbine, Potassiumag individually, or in combination with organic fertilizer (compost), and natural mineral rock (rock phosphate), as a substituent of chemical fertilizer. Two drip irrigation schedules W1 (100%) and W2 (60% of field capacity FC) were applied to evaluate growth and biochemical traits of Moringa oleifera under varying biofertilizer inputs. The highest values of plant growth under W1 were recorded in the plants amended with BioMix1 (Microbine mixed with rock phosphate and compost), plant height (150 cm), number of branch plant−1 (19), plant dry weight (203 g). On the other hand, individual application of Potassiumag (Bio3) showed the highest of plant growth under W2 water scheduling, with plant height (130 cm), number of branch plant−1 (17), plant dry weight (137 g). The present work evaluated a broad range of both non-enzymatic antioxidant components including phenolics, proline, ascorbate and carotenoids, in addition to peroxidase (POD), ascorbate peroxidase (APX) and catalase (CAT) enzymes. Microbine with compost and rock phosphate improved Moringa oleifera yield and quality at 100% FC, while Potassiumag followed by Phosphorine sustained growth under drought 60%FC.

Partial root-zone drying enhances antioxidant signaling and physiological resilience in psyllium (Plantago ovata) under arid conditions

ABSTRACT Drought-induced reduction in crop yield is becoming a serious threat worldwide, especially in arid to semiarid regions. The introduction of medicinal plants into cropping patterns in arid regions is a suitable alternative to conventional crops because of their high demand and market value. Keeping in view the situation, an experiment was planned under natural arid conditions to screen out the best psyllium varieties in less time for cultivation in arid regions. The experiment included three psyllium varieties (V1 = Gujrat isabgol-2, V2 = Vallabh isabgol and V3 = Jawahar isabgol-4) and three irrigation regimes (control = CK, partial rootzone drying = PRD and deficit irrigation = DI) and was carried out in a completely randomized design with eight replications. The results of our experiment revealed that although cell stress indicators (electrolyte leakage, relative cell injury, methylglyoxal, malondialdehyde, and hydrogen peroxide contents) were less and photosynthesis, water relationships, and membrane stability were greater in the control irrigation, the activities of enzymatic and nonenzymatic antioxidants were greater in the PRD and DI regimes. Among the water deficit treatments, more water potential, proline contents, ascorbic acid contents, membrane stability index, and yield were recorded in the PRD than in the DI. Among the varieties, V3 performed the best under water deficit conditions, whereas variety V2 presented the lowest values. It was concluded that under less water availability, the combination of the PRD with the variety V3 optimized physiological and yield outcomes by sustained higher relative water contents (77.10%), mesophyll conductance (0.67 mol CO2 m−2 s−1 bar−1), photosynthesis (15.10 µmol of CO2 m−2s−1), and membrane stability index (78.80%). Consequently, maximized water use efficiency (0.21 g L−1) and antioxidant activities, leading to higher yield (0.76 g plant−1). Future research should focus on integrating PRD with other water management techniques like mulching, osmoprotectants spray to enhance its efficacy under water deficit conditions.

Role of Integrated Soil Amendments in Improving Growth, Physiology, and Nutrient Use Efficiency of Citrus Rootstock Under Drought Stress