Bhavani, P.VASANI FORAM PARESH2023-05-312023-05-312023-05-31Th-13664https://krishikosh.egranth.ac.in/handle/1/5810197489Rice is a major crop used by two-thirds of the population over the world as a staple food. Drought stress is the most important constraint in rice production. Plant sterols, generally known as phytosterols, are integral components of the membrane lipid bilayer. Their levels are high in plants when exposed to drought stress, which implies that phytosterols and their esters may have a role in tolerance to drought stress by reinforcing the cell membranes. The levels of two major phytosterols, campesterol and stigmasterol were analysed to check for their association with different levels of drought stress. Seeds were sterilized and grown in Hoagland media for 10 days. Thereafter, drought was induced with solution of PEG-8000 in varying concentrations (0, 5, 10 and 15 %) for 10 days. The total sterols were then extracted in hexane and analysed using RP-HPLC where the injection volume was 20 μL and the detection was done at 210 nm. Phytosterol concentration was observed to have increased in all the genotypes as the level of PEG treatment increased. The genotype VARY MALADY showed the highest concentration of campesterol whereas UPRH 31 showed the highest level of stigmasterol among the seven genotypes analyzed. It was observed that phytosterol levels are high in plants exposed to drought stress, which implies that phytosterols and their esters may have a role in tolerance to drought stress by reinforcing the cell membranes. There is evidence that an increase in Steryl Ester (SE) level during aging and senescence is a mechanism for recycling of the membrane lipid sterols, a similar mechanism may be at work during stress conditions which is also associated with catabolism of membrane lipids.EnglishThesis