INFLUENCE OF 28-HOMOBRASSINOLIDE ON PHOTOCHEMICAL EFFICIENCY IN BRASSICA JUNCEA UNDER DUAL STRESS OF EXTREME TEMPERATURES AND SALT Page No: 4205-4213

Harpreet Kaur, Geetika Sirhindi and Renu Bhardwaj

Keywords: Brassica juncea, temperature stress, salt stress, 28-homobrassinolide, photosynthesis, photosystem II

Abstract: The plants of Brassica juncea L. cv. RLC-1 were supplemented with 28-homobrassinolide (28-homoBL), exposed to dual stress of low and high temperatures along with salinity in the controlled environment, showed inhibitory effect on growth, photosynthetic pigments and efficiency of PSII. 28-homoBL mitigated the noxious effect of dual stress on B. juncea plants by promoting chlorophyll pigments which ultimately enhanced the photosynthetic efficiency of PSII reaction centres (RC) significantly. Extreme temperature of 4 and 44°C deteriorated total carotenoids to significant levels as compared to control distilled water plants exposed to (180 mM) NaCl salt or temperatures (24, 4 and 44°C). Our results indicated that 28-homoBL redirects the photosynthetic pigments of developing B. juncea seedlings to modulate the photosystem II activity for supporting photochemical efficiency at above level under single or dual stress of extreme temperature and salt



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