ELECTRON‐MICROSCOPIC STUDIES ON CHLOROPLASTS FROM PHOSPHORUS‐DEFICIENT PLANTS

Abstract

The deficiency of phosphorus results in a series of degradative changes in the chloroplasts. These changes can be divided into 4 overlapping phases and each phase or step reflects the severity of the deficiency. The general degenerative pattern involves first the alteration of the grana‐fretwork organization of the chloroplast membranes and the formation of a highly ordered, but more simplified, lamellar system. Subsequently, as the deficiency becomes more severe, the newly formed lamellar system breaks down. Concomitant with the membrane disorganization of the plastids, large osmiophilic globuli develop. These globuli probably form as a result of the gradual breakdown of the lipoprotein membranes with the lipid material accumulating in the globuli.