DEPENDENCE OF CHLOROPHYLL(IDE) SPECTRAL SHIFTS AND PHOTOACTIVE PROTOCHLOROPHYLLIDE REGENERATION AFTER FLASH IN ETIOLATED BARLEY LEAVES

Absorbance spectroscopy at 77 K was used to investigate the effect of temperature on in vivo chlorophyllide shifts and photoactive protochlo rophyllide regeneration after a saturating flash, which transformed al l protochlorophyllide to chorophyllide. Photoactive protochlorophyllid e present in darkness was stable up to 40 degrees C. The rate of Shiba ta shift and protochlorophyllide regeneration after flash were strongl y temperature dependent in the range 0-25 degrees C. At 0 degrees C, t he shift was still observed but no regeneration occurred. Only slight effects were observed in the range 25-40 degrees C. At all temperature s, the process of protochlorophyllide regeneration was significantly s lower than the Shibata shift. The final chlorophyll shift from 672 to 674 nm was observed up to 40 degrees C. The implication of these resul ts concerning the pigment-protein interactions during the Shibata shif t are discussed.