不同品种薄壳山核桃光合及快速叶绿素荧光诱导动力学特性

Characteristics of Photosynthesis and Fast Chlorophyll Fluorescence Induction Dynamics in Different Pecan Cultivars

以‘Pawnee’、‘Mahan’、‘Stuart’、‘Kanza’和‘Jinhua’5个薄壳山核桃品种结果树为研究对象,对其光合特性及快速叶绿素荧光诱导动力学特性差异进行了研究。结果表明,不同品种薄壳山核桃的光合特征参数存在一定差异,‘Stuart’光合能力最弱,‘Mahan’和‘Pawnee’的光合能力及对光环境的适应能力均大于其它品种,但‘Mahan’对弱光的利用能力较弱;‘Mahan’暗呼吸速率最低,有利于光合产物的积累,‘Stuart’暗呼吸速率最高,消耗较多光合产物;对光合基本指标及其光响应特性的分析结果表明,气孔导度、蒸腾速率及瞬时羧化效率是影响净光合速率的重要因素,其中瞬时羧化效率对净光合速率有更直接显著的影响;相较于其它品种,‘Pawnee’抗旱能力较差,而‘Jinhua’抗旱能力较强;JIP-测定结果中,‘Stuart’质体醌容量(Sm)及电子传递活性较大,其各相荧光信号较弱,热耗散的能量较少,导致用于电子传递的能量较多,‘Kanza’的这些特性与‘Stuart’相反;品种间性能指数存在显著差异,‘Stuart’光合机构性能最优,‘Kanza’则较差;综合光合能力及光反应阶段的指标,发现5个薄壳山核桃品种中‘Stuart’光反应活性最大,但其光合能力最弱,可能和气孔限制因素、暗呼吸作用较强及光合机构形成的同化力较多地用于氮、硫同化等其它的代谢有关。

With the fruiting trees of five pecan cultivars,‘Pawnee’,‘Mahan’,‘Stuart’‘Kanza’and‘Jinhua’,we examined the difference in photosynthetic characteristics and fast chlorophyll fluorescence induction dynamics characteristics within the cultivars.There was some difference in photosynthetic characteristic parameters among the five cultivars.The weakest photosynthetic capacity was found in‘Stuart’,and the photosynthetic capacity and adaptability to the environment of‘Mahan’and‘Pawnee’were stronger than those of other cultivars,but the ability to use low light in‘Mahan’was relatively small.The Rd of‘Mahan’was smallest,which was good for accumulating the photosynthetic product,while‘Stuart’ap- transport,while‘Kanza’showed the opposite tendency in those characteristics.There were significant differences in performance indexes of different cultivars.‘Stuart’showed optimal photosynthetic apparatus performance and‘Kanza’showed relatively poor performance.By comprehensively analyzing photosynthetic capacity and the indexes of photoreaction stage,it was found that photo reactivity of‘Stuart’was the biggest,but appeared the weakest photosynthetic capacity.This may be explained by stomatal limitation,strong dark respiration and the reason that more assimilatory power formed by photosynthetic apparatus was used for N,S assimilation and other metabolisms.