抄録
The crown in a tea garden is defined as a bell-shaped surface layer in which tea leaves are aggregated. We considered that photosynthetic productivity in the crowns was correlated closely with the position of leaves and relative illuminance. In this paper the activities of CO2 uptake and ferricyanide-supported O2 evolution, chlorophyll content and chlorophyll a/b were measured to clear the light environment of crowns in connection with the spatial position of leaves. The maximum rate of CO2 uptake was attained at least twice a day (8-9 a.m. and 1-2 p.m.) regardless of leaf age and illuminance. The CO2 uptake by 1-year-old, not newly-formed, leaves located about 50 cm above the ground was saturated at low PPFD, suggesting shade-type of leaves as supported by plotting CO2 uptake against PPFD. The O2 evolving activity of isolated chloroplasts was found to be higher in winter. These results suggest that newly-formed tea leaves are sunlit and change into the shaded leaves at the lower position of the crowns in the period from autumn to winter.
