Salicylic acid and thiourea mitigate the salinity and drought stress on physiological traits governing yield in pearl millet- wheat

Abstract

Plant growth is often affected with hampered physiological and cellular functioning due to salinity and drought stress. To assess the effectiveness of plant bioregulators (PBRs) in mitigating abiotic stresses, a double spilt plot field study was conducted with three replications at ICAR-CSSRI, research farm, Nain, Panipat. The study comprised of three deficit irrigation regimes viz., 100, 80 and 60% of crop evapo-transpiration (ET c ) (I 1 , I 2 and I 3 ), four levels of irrigation water salinity i.e. 2, 4, 8, 12 dS m −1 (S 0 , S 1 , S 2 and S 3 ) and two PBRs salicylic acid (SA; G 1 ) and thiourea (TU; G 2 ). Irrigations, as per regimes and salinity, were applied at identified critical stages of wheat and if needed in pearl millet. PBRs were applied as seed priming and foliar sprays at two sensitive stages of respective crops. The trend of plant height, and physiological and biochemical traits was similar under different treatments at both stages, but differed significantly only at reproductive stage. Water deficit caused significant reduction in pearl millet (5.1%) and wheat (6.7%) grain yields. The reduction in grain yield under 8 and 12 dS m −1 was 12.90 and 22.43% in pearl millet and 7.68 and 32.93% in wheat, respectively compared to 2 dS m −1 . Application of either SA (G 1 ) or TU (G 2 ) significantly enhanced plant height and grain yield, but magnitude of the increment was higher with SA in pearl millet and with TU in wheat. Application of SA and TU increased grain yield by 14.42 and 12.98 in pearl millet, and 12.90 and 17.36% in wheat, respectively. The plant height, RWC, TC, MI, LP, proline, Fv/Fm and Na/K ratio significantly reduced by salinity stress in pearl millet and both water and salinity stress in wheat. Application of both PBRs proved beneficial to mitigate adverse effect of water deficit and salt stress by significantly improving physiological traits, biochemical traits and ultimately grain yield in both crops.

Drought tolerance inBrassica napusis accompanied with enhanced antioxidative protection, photosynthetic and hormonal regulation at seedling stage

“…under drought stress (Figure 8C). A similar additive response was previously observed in Brassica rapa (Lee et al, 2019), Avena sativa Sanchez-Martin et al, 2015), and Triticum aestivum (Yadav et al, 2020) under drought stress indicating that SA production parallels the physiological impact of drought stress. Furthermore, cross-communication between SA and JA signaling pathways has been extendedly reported in response to environmental stresses, oriented to fine tune the transcriptional program determining the resistance mechanism in crop plants (Naeem et al, 2012;Kachroo et al, 2020).…”

Effect of Salinity Stress on Various Growth and Physiological Attributes of Two Contrasting Maize Genotypes

“…Which resulted in low concentrations of assimilates in the leaves [9]. Reduced grain dry matter was appeared due to these low concentrations and poor translocation of assimilates [28]. The net photosynthesis rates were greatly decreased by high salinity.…”

Abiotic Stress Tolerance in Crop Plants: Role of Phytohormones

“…It was postulated from this study that SA acts as an up-streaming signaling molecule under chilling tolerance of cucumber plants via increasing antioxidant defense system and modulating the expression of chilling stress-responsive genes. In a comparative study involving three deficit irrigation regimes, viz., 100, 80, and 60% of crop evapo-transpiration and four levels of salinity, that is, 2, 4, 8, and 12 dS m −1 , the effect of SA in pearl millet and wheat plants was studied [54,55]. Water and salinity stress caused significant reductions in grain yields, plant height, water and proline content, and Fv/Fm and Na/K + ratios in both pearl millet and wheat plants.…”