Heat caused redn. in membrane protein thiol content, increased accumulation of thiobarbituric acid reactive substances
and reduced germination rate and early growth in germinating Amaranthus lividus seeds. Imposition of heat stress
during early germination also causes accumulation of reactive oxygen species like superoxide and hydrogen peroxide
while activities of antioxidative enzymes catalase, ascorbate peroxidase, and glutathione reductase decreased. Calcium
chelator (EGTA), calcium channel blocker (LaCl3) and calmodulin inhibitor (trifluoperazine) aggravated these effects.
Added calcium reversed the effect of heat, implying that protection against heat induced oxidative damage and
improvement of germination requires calcium and calmodulin during the recovery phase of post-germination events in
Amaranthus lividus.