Physiological and Biochemical Basis of Extended and Sudden Heat Stress Tolerance in Maize

Abstract

Effects of extended and sudden heat stress on various physiological and biochemical processes have been investigated in ten inbred lines of maize (Zea mays L.) at seedling stage. Among the various parameters studied, a significant decrease was observed in membrane stability, chlorophyll fluorescence and chlorophyll concentration under extended heat stress and sudden heat shock in sensitive genotypes which indicated their susceptibility to high temperature. However, heat tolerant genotypes exhibited less impact on these parameters which could be attributed to lesser oxidative stress injury. The free radical scavenging system in heat tolerant genotypes was observed to be better established as compared to heat sensitive genotypes. These findings suggested that the genotypes which performed better both under extended and sudden heat stress conditions could be partly due to their superior ability to cope up with oxidative damage caused by heat stress in maize.