Ecology, Environment and Conservation Paper

SALICYLIC ACID DECREASE THE SUSCEPTIBILITY OF PHOTOSYSTEM II AND PHOTOSYNTHESIS FROM HEAT STRESS INJURY IN WHEAT (TRITICUM AESTIVUM L.)

Shailesh Kumar, Virendra Pal Singh, Ajay Arora and Sweta Mishra

Abstract

Heat stress adversely affects the overall photosynthetic process by causing a decline in the turnover of important proteins associated with Photosystem II (PSII) and calvin cycle. The molecular mechanism behind SA regulating the protection of Photosystem II (PSII) and other photosynthetic machinery during high temperature stress is not completely known. This study was designed to analyse the role played by application of exogenous salicylic acid (SA) on protection of PSII and other photosynthetic machinery in wheat from the adverse effects of heat stress. Our findings revealed that under heat stress, salicylic acid (SA) treated wheat plants sustained higher chlorophyll content, photochemical activity of PSII and the photosynthetic rate than in the heat stressed plants without SA treatment. The expression of gene TapsbA (encoding D1 protein), TapsbO (encoding protein of oxygen evolving complex) and TarbcS (encoding Rubisco small subunit) were unregulated in SA-treated plants as compared to that of heat stressed plants without SA treatment. In addition, foliar spray of SA also stabilised the membrane. We also observed that the foliar application of SA helped in faster functional recovery of PSII which facilitated to maintain higher photosynthesis during heat stress.