Chlorophyll synthetase activity is relocated from transforming prolamellar bodies to developing thylakoids during irradiation of dark‐grown wheat

Abstract

Analyses of the esterification of newly formed chlorophyllide in irradiated dark‐grown leaves of wheat (Triticum aestivum L. cv. Kosack) suggest a translocation of chlorophyll synthetase activity from transforming prolamellar bodies to developing thylakoids. We have fractionated plastid inner membranes from dark‐grown leaves and from leaves irradiated for 5, 10, or 20 min and compared the in vitro esterification of chlorophyllide in two fractions, corresponding (in density) to the prolamellar body and the prothylakoid fraction of dark‐grown leaves. The relative amounts of chlorophyllide, and total protein, as well as the specific esterification activity, increased with irradiation time in the prothylakoid fraction. The esterification of chlorophyllide seems to depend on a transformation of the prolamellar body structure. The results are discussed also in relation to other events initiated by irradiation, such as the Shibata‐shift and the altered distribution of NADPH‐protochlorophyllide oxidoreductase (EC 1.3.1.33).