The Effect of Dormancy on the Heat Shock Response in Gladiolus Cormels

Cormels of Gladiolus X gandavensis Van Houtte respond to heat shock by an induced synthesis of heat shock proteins. Synthesis of some of the non-heat shock proteins is concomitantly reduced. The ability of dormant cormels to synthesize heat shock proteins (hsps) and to repress the synthesis of non-hsps is greater than that of nondormant ones. A hsp of apparent molecular weight 68 kilodaltons is synthesized only in dormant cormels or in cormels that lost their dormancy after long storage at 25 degrees C. The synthesis of hsps at 40 degrees C, but not at 25 degrees C, is promoted by abscisic acid in nondormant cormels. Methionine incorporation into hsps declines after a 4-hour incubation period at 40 degrees C. Induction of hsps is stronger if exposure to extreme temperature is done gradually.