甜樱桃植株不同冠层部位光合特性及果实品质的研究

Photosynthetic Properties and Fruit Quality in Different Parts of Sweet Cherry Canopy

在横断山北段台地选取5株甜樱桃植株,应用Li-6400XP光合测定系统和用CI-700AB/HR2000光纤光谱仪研究其不同植株冠层部位对生理辐射光谱、光合特性及果实品质的影响。结果表明:(1)甜樱桃树冠下层和内部表观量子效率(α)最高,且光补偿点(LCP)最低,对弱光的利用能力强,而在树冠上层和外层光饱和点(LSP)极显著高于下层和内部,利用强光的能力强。(2)甜樱桃植株冠层的生理辐射由树冠的下层至上层、以及由内部至外部逐渐增强,短波光所占比例增大,说明甜樱桃对环境强光和相对弱光都具有一定的适应能力。(3)甜樱桃植株树冠上层叶片的最大光合速率(Pmax)、暗呼吸速率(Rd)、LCP和LSP均极显著高于下层,其光合同化以及代谢能力强;且生理辐射强、短波光多,利于甜樱桃果实可溶性固形物(TSS)、Vc及糖积累,但不利于有机酸积累。

Five representative sweet cherry trees were selected from northern part of Hengduan Mountains for comparing physiological radiation,photosynthetic properties and fruit qualities of sweet cherry, especial- ly analyzing light response of photosynthesis （Pn-PPFD） response curve and the correlation between fruit qualities and physiological radiation and photosynthetic parameters of sweet cherry. The results showed that： （1）The apparent quantum yield （α） was the highest,while light compensation point （LCP） the low- est in the substrate and inner part of canopy,which indicated sweet cherry leaves had a good ability of utili- zing the low light. However,the light saturated point （LSP） was significantly higher in the top and outer part of canopy,which showed sweet cherry leaves had a good ability of utilizing the strong light. （2）The physiological radiation intensity and ratio of short wave light increased from the substrate to the top part and from the inner to the outer part of canopy. Thus, they indicated that sweet cherry reflected great capa- bility of adapting to low or strong light. （3）The maximum photosynthetic rate （Pmax）,dark respiration rate （Rd） ,LCP and LSP were the highest in the top and outer part of canopy,enhancing leaves used efficiency to light intensity,increasing leaves ability of utilizing the strong light. The physiological radiation and short wave light intensity were strong, TSS, Ve and total sugar contents increased, but organic acid content re-duced.