Effects of Heat Shock on Growth and on Lipid and beta-Glucan Synthetases in Leaves of Phaseolus vulgaris and Vigna sinensis

Abstract

Primary leaves of intact plants of Phaseolus vulgaris and Vigna sinensis 7 to 9 days old were dipped in water for 2 minutes at 47.4 +/- 0.2 C and 48.7 +/- 0.5 C, respectively. Leaf growth was inhibited within the first 20 hours, and growth partially or completely recovered in a subsequent 20-hour period. Analysis of the glucolipid and beta-1, 3- and beta-1, 4-glucan synthetases showed that the most evident effects of heat shock were the severe inhibition of the synthesis of beta-1, 4-glucosyl glycosidic linkages and stimulation of beta-1, 3-linkage synthesis. The stimulation appeared either immediately after treatment or within the first 20 hours and lasted at least 60 hours after treatment. Phaseolus plants reacted more intensely to the heat shock, reflecting a possible genetic difference in the response mechanisms.