Indian Journal of Plant Physiology

In the present study an attempt was made to assess whether genetic variability in thermotolerance in wheat (Triticum aestivum L.) was associated with the differential accumulation and expression of high molecular weight (HMW) and low molecular weight (LMW) heat shock proteins (HSPs). Seedlings of wheat cvs. HD 2285 and UP 2338 (temperature tolerant) and cvs. HD 2428 and HD 2329 (temperature susceptible) were subjected to a gradual temperature induction (30°C,1hà33°C,1hà37°C,2h) followed by a severe lethal temperature stress (46°C,3h). The seedlings were allowed to recover for 68 hrs and growth during recovery was taken as a measure to quantify the relative thermotolerance of these cultivars. The temperature induced seedlings of thermotolerant cultivars showed higher recovery growth and greater ability to acquire thermotolerance as revealed by 2,3,5-triphenyl tetrazolium chloride (TTC) test. The higher recovery growth of temperature induced seedlings of tolerant cultivars was associated with the enhanced accumulation and expression of both HMW as well as LMW HSPs. However, unlike the HMW HSPs which showed constitutive expression even under non stress conditions, LMW HSPs were observed to be induced only under high temperature stress.