ROLE OF CALYX LOBES IN GAS-EXCHANGE AND DEVELOPMENT OF PERSIMMON FRUIT

The role of calyx lobes in CO2 exchange in persimmon (Diospyros kaki T hunb.) fruit was investigated during fruit growth and development, Car bon dioxide exchange rates of attached and detached fruit were measure d in light and dark conditions in the field after calyx lobes were rem oved. Calyx lobes were removed at fruit growth stages I and III, which were defined as the period when fruit diameter increases >0.3 mm d(-1 ) (Zheng et al., 1990). Removing calyx lobes at stage I significantly inhibited fruit growth, while removing them at stage III had no effect on growth, Two weeks after calyx lobes were removed at stage I, CO2 e xchange decreased 80% in light and dark conditions compared with the c ontrol fruit. The rapid decreases of CO2 exchange rate by calyx lobe r emoval at stage I were obvious if expressed per fruit or on a fresh we ight basis. In contrast, treatment at stage III had no effect on CO2 e xchange rate of fruit and no effect on fruit growth. However, when the calyx lobe scars were sealed with Vaseline soon after calyx lobe remo val at stage III, an immediate decline in CO2 exchange rate in the dar k occurred with simultaneous inhibition of the final swell in fruit gr owth. A possible relationship between fruit growth potential and gas-e xchange capacity is discussed.