Heat shock induces synthesis of plastid-associated hsp70 in etiolated and greening pumpkin seedlings.

Heat shock proteins of hsp70 family with molecular weight of 76 and 73 kDa were detected both in etiolated as well as in greening pumpkin seedlings using immunoblotting technique. Both proteins exhibited heat shock inducibility and their apparent amount depended on the plant organ examined as well as on the greening time. Sucrose density gradient centrifugation revealed that the 76 kDa band should be attributed to chloroplasts and the 73 kDa band to mitochondrial fraction. The 76 kDa band dominated in cotyledons and was hardly detectable in root preparation whereas the 73 kDa band was prevailing in hook samples but was also clearly detectable both in cotyledons and in roots.