Implications of reactive oxygen species in heat shock induced germination and early growth impairment in Amaranthus lividus L.

Abstract

An effort has been made to assess the role of reactive oxygen species in germination and subsequent growth of Amaranthus lividus under elevated temperature. Transfer of A. lividus seeds from 25 to 45°C for 4, 8 and 12 h, during early imbibitional period reduced percentage of germination, relative germination performance, relative growth index and seedling length. Heat shock during early germination decreased also the activities of free radical scavenging enzymes like catalase, peroxidase and superoxide dismutase, increased the accumulation of superoxide, hydrogen peroxide and induced lipoxygenase mediated membrane lipid peroxidation. Membrane injury index and relative leakage ratio revealed a rise with concomitant reduction in membrane protein thiol content in heat shock raised seedlings. The results indicate that heat shock in A. lividus seeds induced an excessive generation of ROS and led to an oxidative membrane damage, causing early growth impairment.