果実発育時のオウトウ樹における環境条件および樹冠構成要素が光合成および光合成産物の転流に及ぼす影響

Abstract

The net photosynthetic rate of the current shoot leaves of sweet cherries (Prunus avium L.) at 40d after full bloom (DAFB) in the field peaked at 9 A.M. at 17.2, μmol CO2 m-2 s-1, and then decreased gradually, probably due to the increase in leaf temperature and the decrease of relative humidity. The net photosynthetic rate in leaves on spurs with fruit on fruiting trees was higher than the rate in leaves on spurs without fruit on fruiting trees and non-fruiting trees. Chlorophyll concentration in spur leaves with fruit on fruiting trees was also higher than that in spur leaves without fruit on fruiting trees. Therefore, the effect of fruiting in cherry trees may appear locally rather than wholly in the trees. The net photosynthetic rate in the current shoot leaves was higher than that in the spur leaves. 13C-photosynthates in both current shoot and spur leaves tended to translocate abundantly closer to the fruit from 13C-fed leaves. Whereas when all leaves were defoliated except for 13C-fed leaves, 13C-photosynthates were translocated almost uniformly to each fruit irrespective of the fruiting position because the source for each fruit was limited by the defoliation.