去果、枝条环剥和新梢套袋后桃树叶片可溶性糖含量的变化对光合作用的影响

以‘绿化九号’桃(Prunus persica(L.) Batch)为试材,在果实最后迅速生长期,通过去果降低叶片中糖分往果实中的运输,新梢套袋等措施改变光照时间,减少光合同化物的积累,并通过新梢左右两端环剥阻止同化物向其他果实和枝条运输,形成一个叶片中糖分浓度梯度,研究不同叶片糖分浓度梯度下,源叶净光合速率(Pn)、叶绿素荧光、叶片中可溶性糖含量等的变化。同时,通过叶绿素荧光参数分析了在库源调控造成叶片可溶性含量不同时,Pn下降可能的调控机制。结果表明,和留果对照相比,去果造成叶片可溶性糖含量最高,而套袋使叶片可溶性糖含量最低。伴随着叶片可溶性糖含量的增加,Pn和气孔导度(Gs)下降,而叶片温度(tleaf)增加。Pn和Gs之间极显著正相关。而tleaf的增加则伴随着光系统Ⅱ最大量子产额(Fv/Fm)、光系统Ⅱ实际光化学效率(ΦPSⅡ)和光化学猝灭系数(qP)的下降,相反,tleaf增加,非光化学猝灭系数(NPQ)增加。因而,叶片可溶性糖的积累有可能通过某种方式影响Gs并使之降低,造成蒸腾作用减少,最后使叶片tleaf升高,有可能限制了PSⅡ反应中心的光化学效率,从而对光合作用做出调节。

Effects of Fruit Removal,Shoot Girdling and New Shoot Bagging on Leaf Soluble Sugar Content and Photosynthesis of Peach Leaves

In 'Lvhua 9' peach(Prunus persica(L.) Batch) trees,a series of source leaves with differing levels of soluble sugar content were created by retaining fruit(+fruit),removing fruit(-fruit) or reducing the light period.To alter the light period,leaves were covered with a bag made of brown inner paper and outer silver paper,which was then removed at different times the next day.The highest level of leaf soluble sugar content was obtained by fruit removal,while reducing the light period resulted in a lower level...