不同矮化中间砧对苹果苗光合特性的影响

Effects of different dwarfing interstocks on photosynthetic characteristics of grafted apple trees

【目的】对2种矮化中间砧盆栽嫁接苹果苗的光合指标和叶绿素荧光参数变化进行研究,揭示苹果中间砧对嫁接植株光合机理的影响。【方法】以八棱海棠为基砧,M9和M26为矮化中间砧,2年生"长富2号"为嫁接材料,设八棱海棠同龄砧嫁接"长富2号"为对照,分析M9和M26矮化中间砧对嫁接苗比叶重、叶绿素和类胡萝卜素含量、光合指标(净光合速率、胞间CO2浓度、气孔导度、蒸腾速率)及日变化、叶绿素荧光参数和其日变化的影响。【结果】M9和M26矮化中间砧嫁接苗的净光合速率显著高于对照嫁接苗,而气孔导度、胞间CO2浓度和蒸腾速率较低。M9和M26矮化中间砧嫁接苗的Fm、Fv/Fm和Fv/Fo显著低于对照嫁接苗,但qN、ETR、NPQ却高于对照嫁接苗。经过中午的强光和高温后,M9和M26矮化中间砧嫁接苗的Fo显著下降,NPQ和ETR明显升高,而对照嫁接苗的Fo显著上升,NPQ和ETR升高不明显,Fo的升高表明对照嫁接苗的PSⅡ反应中心由于强光破坏而明显失活。【结论】矮化中间砧影响下的苹果苗防御强光破坏的机制与对照嫁接苗不同,矮化苗的光能调节能力更强,其因具有较高的净光合速率而早产。

[Objective]The photosynthetic indexes and chlorophyll fluorescence parameters of grafted apple trees with two dwarfing interstocks were investigated to reveal the photosynthetic mechanism of apple trees grafted on dwarfing interstocks.[Method]Using M.micromalus as rootstock and biennials Nagafu No.2as grafting material,the effects of M9 and M26as dwarfing interstocks on leaf quality,contents of chlorophyll and carotenoid,photosynthetic indexes（net photosynthetic rate,intercellular CO_2 concentration,transpiration rate,and stomatal conductance）and their diurnal variations,as well as chlorophyll fluorescence parameters and their diurnal variations were compared to biennials Nagafu No.2grafted onto M.micromalus as control.[Result]Photosynthetic rates of apple trees grafted on M9 and M26were significantly higher than that of the control while stomata conductance,intercellular CO_2 concentrations and transpiration rates were lower.The Fm,Fv/Fmand Fv/Fo of apple trees grafted on M9 and M26were significantly lower than the control,while qN,ETRand NPQ were higher.After the strong light and hightemperature at noon,Fo of apple trees grafted on M9 and M26declined significantly,while NPQand ETR rose obviously.In contrast,Foof control group rose significantly,while NPQand ETRrose insignificantly.The increase of Foindicated that PSⅡ reaction center of control group deactivated due to the damage of strong sunlight.[Conclusion]The photosynthetic mechanism of trees grafted on M9 and M26dwarfing interstocks in defensing strong sunlight damage was different from grafted trees in control group.Trees grafted on dwarfing interstocks had stronger light regulation,higher net photosynthetic rate and earlier harvest time.