HEAT-SHOCK INDUCES SYNTHESIS OF PLASTID-ASSOCIATED HSP70 IN ETIOLATEDAND 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 se edlings using immunoblotting technique. Both proteins exhibited heat s hock inducibility and their apparent amount depended on the plant orga n examined as well as on the greening time. Sucrose density gradient c entrifugation revealed that the 76 kDa band should be attributed to ch loroplasts and the 73 kDa band to mitochondrial fraction. The 76 kDa b and dominated in cotyledons and was hardly detectable in root preparat ion whereas the 73 kDa band was prevailing in hook samples but was als o clearly detectable both in cotyledons and in roots.