The effect of kinetin on chlorophyll synthesis in ageing etiolated barley leaves exposed to light

Etiolated barley seedlings lose the ability to produce chlorophyll and soluble protein on exposure to light with increasing age. Similarly, the production of δ-aminolaevulinic acid-dehydratase and succinyl-CoA synthetase is decreased in older etiolated leaves exposed to light. The rate of protochlorophyllide₆₅₂ regeneration decreased well before the rates of exogenous δ-aminolaevulinic acid conversion to protochlorophyllide₆₃₂ was affected by ageing. Application of kinetin retarded these ageing symptoms in the etiolated leaves.