CHLOROPHYLL FORMATION IN ISOLATED PUMPKIN COTYLEDONS IN THE PRESENCE OF KINETIN AND CHLORAMPHENICOL

Investigations have been made on the changes in the levels ofprotochlorophyll, chlorophyll a and chlorophyll b in relationto the kinetin induced expansion of isolated pumpkin cotyledonsin the presence and absence of chloramphenicol. It has been shown that rise in pigment level keeps pace withexpansion growth of the cotyledons. Kinetin markedly promotes the synthesis of protochlorphyll withoutmuch affecting the rate of its photoreduction to chlorophyll. Chloramphenicol strongly inhibits the development of both chlorophylla and b. The inhibition seems to be due to its interferenceboth with the synthesis of protochlorophyll and its subsequentconversion to chlorophyll. The inhibitory effect of chloramphenicol on the formation ofchlorophyll a is greater than on that of chlorophyll b, suggestingthereby the probability of divergent pathways for the formationof the two chlorophylls. (Received December 21, 1966; )