Chloroplast culture VIII a new effect of kinetin in enhancing the synthesis and accumulation of protochlorophyllide invitro

By pretreating etiolated cucumber cotyledons with kinetin in the dark, it was observed that the plastids isolated from such tissues were 400% more active in the conversion of δ-aminolevulinic acid into protochlorophyllide, than plastids prepared from water-treated controls. The experimental evidence is consistent with the hypothesis that (a) the kinetin dark-pretreatment of the etiolated tissue, uncouples the joint biosynthesis of prothylakoids and protochlorophyll and results in the accumulation of excess prothylakoid membranes poorly supplied with protochlorophyllide (b) upon isolation of the plastids and incubation with δ-aminolevulinic acid, the latter is very rapidly converted into membrane-bound protochlorophyllide.