果实的有无对桃叶片净光合效率及相关生理反应的影响

 将‘燕红’桃在果核硬化期和果实最后迅速生长期留果对照和去果比较, 去果(库) 后叶片(源) 净光合速率( P_n) 、气孔导度( G_s) 和蒸腾速率( E) 降低, 叶片温度( T_leaf ) 升高, 对细胞间隙CO₂浓度(Ci) 无显著影响。去果对Pn、Gs、E和Tleaf的影响主要发生在9: 00～16: 00之间, 且在中午前后一段时间里影响最显著。研究叶片P_n与G_s之间的关系表明, 当G_s值小于60 mmol·m ^{- 2} ·s^{- 1}时, 二者呈极显著正相关。此外, 留果对照和去果处理间叶片Pn差值与T_leaf差值呈显著或极显著的正相关。去果降低库力, 减少叶片G_s并导致叶片温度的增加可能是源叶P_n降低的关键因素。

Effect of Sink-source Change on Net Photosynthesis and Related Physiological Response in Peach Trees(Prunus persica)

The effect of defruiting on source leaf net photosynthesis ( Pn) and related physiological response was investigated on ‘Yanhong’peach trees ( Prunus persica) during the fruit stone hardening and final fruit rap id growth stage. The results showed that Pn, stomatal conductance (Gs) and transp iration ( E)in source leaves decreased significantly while leaf temperature ( Tleaf ) increased from defruiting trees as compared with those from fruiting ones. There was, however, no significant difference of substomatal CO₂ (Ci)between fruiting and defruiting treatments. The effect of reducing the sink activity by defruiting treatment on Pn, Gs, E and Tleaf appeared during 9: 00 and 16: 00. The relationship between Pn and Gs was significantly positive only when Gswas less than 60 mmol·m^{- 2} ·s^{- 1}. The difference of Pn between fruiting and defruiting increased with the increasing difference of Tleaf between defruiting and fruiting treatments. It is suggested that an increasing Tleaf , resulting from the stomatal closure, may be a key factorwhich leads the decrease of leaf Pn in reducing the sink activity in fruit trees.