Synthesis of heat-shock protein and acquisition of thermotolerance in high-temperature tolerant and high-temperature susceptible lines of Sorghum

Abstract

Exposure of 24–40-hour-old Sorghum bicolor seedlings to heat shock (HS) resulted in depression of normal labelled amino acid incorporation into protein and rapid production of a small number of heat-shock proteins (HSP). Seedlings were also capable of acquiring tolerance to elevated temperatures (45–50°C) as a consequence of brief pre-exposure at 40°C. However, seeds in the early stages of germination were found to be incapable of HSP synthesis, and HS delivered at 16 h after the start of inhibition led to a general reduction in incorporation of labelled amino acid in embryos. Varietal differences were apparent in the time at which the capacity to synthesise HSP first appeared, and the particular susceptibility of early germination processes in some Sorghum lines to high temperatures may be related to their inability to synthesise HSP and acquire thermotolerance.