Anatomical and physiological changes of fruit tree leaves during greening and senescence

本试验旨在研究结果、不同施氮量、年轮和水分胁迫对几种果树淀粉积累与淀粉酶活性、光合速率(Pn)和Rubisco蛋白的影响。结实效应。果实成熟期果肢叶片的光合作用速率较快。结果树叶片中叶绿素含量高于不结果树。不结果树TH叶绿体中积累的淀粉比结果树的叶片多。类囊体的体积随着叶绿体中淀粉大小的增加而减小。振铃效应。裂叶叶绿体中的淀粉粒在海绵细胞中迅速膨胀。果叶中叶绿素含量低于果叶。在叶绿体中，叶绿体核定位于叶绿体的外围。结果叶的Pn高于果叶。其中，落叶的净光合速率处于补偿点以下。氮气效应。随着土壤施氮量的减少，叶片中叶绿素含量呈下降趋势。不施氮或低施氮处理叶片中淀粉含量的增加幅度均大于施氮量较高的处理，氮素含量随施氮量的增加而增加。淀粉酶活性随着淀粉积累的增加和叶绿素含量的降低而降低。不施氮的叶片中Rubisco蛋白含量最低，且叶片中的积累与淀粉的积累成反比。水压力。无花果叶片因水分胁迫而变黄与叶绿体和叶绿体核的降解有关。在叶片自然衰老过程中，Rubisco蛋白显著减少。

The present experiment was designed to determine the effect of fruiting, different nitrogen application, ringing, and water stress on starch accumulation in relation to amylase activity, photosynthetic rate (Pn), and RuBisCo protein in several fruit trees.1. Fruiting effect. The photosynthetic rate was faster in leaves of fruiting limbs during the fruit maturation stage. The chlorophyll was more concentrated in leaves of bearing than in those from non-bearing trees. Non-bearing trees accumulated more starch in th chloroplasts than leaves of bearing trees. The volume of thylakoid decreased with increasing starch size in the chloroplasts.2. Ringing effect. The size of starch grains in the chloroplasts of defruited leaves expanded rapidly in the spongy cell. The chlorophyll content in defruited leaves was lower than in fruiting leaves. In the chloroplasts of defruited leaves, chloroplast-nuclei were localized at the periphery of the plastids. The pn in fruiting leaves was higher than in defruited leaves. Particularly, the Pn of the defruited leaves were under the compensation point.3. Nitrogen effect. The contents of chlorophyll in the leaves declined in parallel with decreasing the nitrogen application in th soil. The starch content in the leaves without or with lower nitrogen application increased more than those in any-nitrogen application plots.The pn increased with nitrogen application.4. Amylase activity decreased with the incease of starch accumulation and with the decrease of chlorophyll content.5. RuBisCo protein was the lowest in the leaves without nitrogen application and accumulation was in inverse proportion to that of starch in the leaves.6. Water stress. The yellowing of the fig leaves by water stress was related to the degradation of the chloroplast and chloroplast-nuclei.7. RuBisCo protein decreased markedly during the natural senescence of theleaves.