Effect of salicylic acid and brassinosteroid on alleviation of water stress in two wheat cultivars

Drought is one of the most important factors limiting crops growth and production and use of plant growth regulators to cope with water stress is of interest to many researchers. In order to study the effects of two plant growth regulators, brassinosteroid (BR) and salicylic acid (SA) on germination and growth of two wheat cultivars in water deficit conditions, a greenhouse experiment was designed and carried out at College of Agriculture, Shiraz University, Shiraz, Iran in 2014. The experiment was factorial based on randomized complete block design, with four replications. Treatments composed of two wheat cultivars (Shiraz and Sirvan), two moisture regimes (50 and100% FC) and growth regulators (BR and SA). In this experiment water stress significantly increased greenness Index (50.58%) and significantly reduced relative water content (10.24%), spike dry weight (17.22%), one hundred seed weight (14.14%), shoot dry weight (8.74%) and seed weight per plant (19.21%). However, plant spray with 25 and 50 µg.L-1 BR and 1mM SA could offset some of the adverse effects of water stress. Furthermore seed priming with BR increased the percentage and rate of seed emergence. Sirvan as a tolerant cultivar for all of the measured traits was shown to be superior to Shiraz, as a sensitive cultivar.