Partial inhibition of the decay of Hill activity in isolated chloroplasts by kinetin.

Kinetin when included in the grinding medium inhibits degeneration of isolated spinach chloroplasts. This is indicated by the relatively greater retention of Hill activity by chloroplasts isolated in the presence of Kinetin. It appears that the Kinetin effect is probably on the integrity of the chloroplasts membrane. The technique seems to be of great practical value in photosynthetic studies.