INVOLVEMENT OF SUGAR METABOLISM IN PERSIMMON GROWTH-INHIBITION BY CALYX LOBE REMOVAL

The calyx lobes of persimmon (Diospyros kaki L.) fruit were removed in the middle of growth stage I (18 July) or at the beginning of stage I I (30 Aug.) or stage III (5 Oct.), Removing calyx lobes at stages I an d II severely inhibited fruit development during the rest of the growt h period, while no inhibitory effect was observed when calyx lobes wer e removed at stage III, The average fruit weight at harvest was 56% an d 31% less in the fruit treated at stage I and stage II, respectively, than in control fruit, Changes in concentrations of constitutive suga rs in fruit treated at stages I and II were correlated with fruit grow th inhibition, Fruit treated at stages I and II had significantly less hexoses (i,e., glucose and fructose) and more sucrose than controls, This modified sugar metabolism may be due to a decline of acid inverta se activity, since acid invertase activity was low in fruit in which t he calyx lobes were removed at stages I and II, The involvement of sug ar metabolism in fruit growth is discussed.