Biophysical studies on subcellular particles IV. The light scattering response and photosynthetic activities of spinach chloroplasts treated with n-alkanes

摘要

A suspension of isolated spinach chloroplasts was shaken with one of a series of liquid n-alkanes, from hexane to dodecane, for several sec. Physical and biological activities of alkane-treated chloroplasts were compared with those of untreated ones. The light scattering response, the light-induced pH shift, the ferricyanide-Hill reaction and noncyclic phosphorylation were inhibited by shaking with alkanes, with the exception of undecane and dodecane which temporarily stimulated the latter two reactions. The degree of inhibition was inversely proportional to the chain-length of the n-alkane.This inhibition by alkane treatment was observed in the light scattering response much more strongly than in any other reaction. Thus, we postulated that the light scattering response is attributable to changes in some internal structures that are sensitive to penetrated n-alkane molecules.Electronmicroscopy of alkane-treated chloroplasts revealed that most of the thylakoid sacs were swollen while partitions apparently remained intact. The degree of swelling was also inversely proportional to the chain-length of the n-alkane.