Enhancing the safflower performance and quality by brassinosteroids and salicylic acid foliar application under water stress conditions

World-over, under biotic stress conditions, plant growth regulators are used to increase the growth and production of crops. To evaluate the effect of salicylic acid (SA; ۰ and ۱ mM) and Brassinosteroids (BRs; ۰, ۰.۷۵ and ۱ μM) foliar application on seed and oil yield and physiological and biochemical responses of safflower under water deficit (۱۰۰ and ۵۰% F.C., I۱۰۰, and I۵۰), an experiment was carried out in a factorial on a randomized complete block design with four replicates in the research greenhouse of Agriculture Faculty, Shahid Bahonar University of Kerman during ۲۰۲۳. Grain yield per plant and its components, as well as seed oil content and oil yield of safflower, were reduced under I۵۰ treatment. Moreover, I۵۰ stress, increased the concentrations of malondialdehyde (MDA), hydrogen peroxide (H۲O۲), and electrolyte leakage (EL) as well as osmolyte accumulation (soluble sugars and proline) and anti-oxidant enzymes activity of safflower leaves. In addition, SA and BRs application significantly increased the anti-oxidant enzyme activity and the osmolyte contents and, in contrast, decreased the concentrations of MDA and H۲O۲ as well as EL, however, the positive effect of SA on these parameters was highest when applied simultaneously with BRs. Also, SA, and BRs applied increased the seed oil content and oil yield of safflower, but the effect of BRs and SA together was greater than that of SA or BRs applied separately. Overall, water-stress alleviation and yield improvement in safflower by BRs and SA application was attributable to partly improved osmotic adjustment (accumulation of osmolytes), cell membrane stability and antioxidant activity under stress conditions. Foliar applications of SA and BRs had great potential in improving growth and seed and oil yield of safflower under water stress conditions.

Enhancing the safflower performance and quality by brassinosteroids and salicylic acid foliar application under water stress conditions Keywords:

Cell membrane stability , Plant growth regulators , Oil yield , Cell membrane stability , Plant growth regulators , Oil yield