Ecology, Environment and Conservation Paper

HIGH TEMPERATURE TOLERANCE IN RELATION TO CARBOHYDRATE METABOLISM IN BARLEY

Sondeep Singh, Bavita Asthir and N.S. Bains

Abstract

Effect of high temperature in relation to carbohydrate metabolism was studied in the developing grains of heat susceptible (VJM 540) and heat tolerant (VJM 318) genotypes of barley during timely sown (December 2005) and in the late sown crop (January 2005).Activities of acid- and neutral invertase, sucrose synthase and total amylase showed their peak activity one week earlier during late sown conditions when compared to timely sown crop. In general, acid invertase activity predominated over neutral invertase activity in both genotypes. A premature cessation of starch deposition occurred during late sown conditions due to shortening of grain filling period which was not compensated by higher rate of grain growth. The more reduction in starch content was not due to assimilate supply rather its utilization is affected at higher temperature.