High Temperature Tolerance in Relation to Changes in Lipids in Mutant Wheat

Abstract

Radiation-induced high temperature-tolerant spring wheat mutant WH 147M and its mother cultivar WH 147 (sensitive) were grown in phytotrons at day/night temperature of 37°C/18°C (stress) and 20°C/ 12°C (normal) for 12 h each and fluorescent light (5.34 J/cm2/h) for 12 h per day. Grains of WH 147M had A considerably higher content of phospholipids than WH 147. In leaf samples of both the genotypes polar lipids constituted 80 to 90 per cent of the total lipids. But galacto-, phospho- and neutral lipid content was higher in leaf samples of heat-stressed plants of both genotypes than the normal ones. Similarly, increase of monogalactosyl diglycerides (MGDG) predominated over that of digalactosyl diglycerides (UGDG) under normal temperature. The mutant showed a higher content of galatolipid-bound linolenic acid and especially phospholipid-bound trans-(delta)-3-hexfldecenoic acid than the heat sensitive WH 147. Following heat stress, increase in these parameters was less pronounced in the mutant than in WH 147. These observations indicate the role of membrane lipids in adaptation to heat stress.