源库关系失调对核桃光合同化产物输配的影响

The relationship between source and sink is the physiological basis of fruit tree high yield.It is important to elucidate the physiological effects of source-sink adjusting modes on fruit yield formation for deepening physiological and ecological theory of fruit high-yielding and guiding fruit high-yielding cultivation with different spike types.Some results showed that the photosynthetic characteristic of leaves，fruit weight，the quality of fruit can be changed under different source and sink relationship.There are few reports about the research of relationshiop between source and sink effort on source，sink and flow of fruit.With the characteristic of precious，thin shell thickness and high yield of Xinjiang walnut，it is the predominant industry in Tarim Basin regions and has become mainly farmer’s economic income source. The cell of kernel has full of oil bodys and the content of fat is about 60%.But with the expansion of cultivated area，the quality and quantity of walnut was declining.After our investigation，the percentage of nut with kernel oilness was about 10%.The walnut has many source-sink ratio in nature，and we found that the quality and quantity of fruits was closely related to source-sink ratio. It is not clear that how does the source-sink ratio effect on the quality and quantity. The walnut as material which under different source-sink relationship，the photosythate product and unloading of sugars，the phloem transport and carbon assimilation partitioning，the unloading at the sinks and fruits development will study in this project. By the results of these rearch，we want to explore the direct evidences by the studies of photosynthesateds input and test hypothesis.The purpose of this study is to comprehensive understand the reason why the quality and quantity can be change under different source-sink relationship and can provide theoretic basis for yield of walnut， which is essential for the development of walnut in Xinjiang.

源库协调是果树高产高质的生理代谢基础，明确源库调节对果树产量、品质形成的生理影响对于深化高产高质生理生态理论和指导高产栽培具有重要的实践意义。已有的果树源库关系研究主要集中在人工调控下的叶果比对叶片光合特性、果实重量和品质的影响方面，而自然状态下叶果比对光合同化产物输配的影响鲜有报道。新疆早实核桃品种为典型自然状态下存在多种叶果比的果树。本项目拟以新疆早实核桃为研究材料，通过叶果比对核桃叶“源”光合同化产物形成和装载路径、韧皮部“流”运输和同化物分配、果实“库”的光合同化产物卸载和生长发育特性的研究，解析源库关系对核桃光合同化产物输配的影响，检验“源库关系失调导致的光合同化物输配失衡是影响核桃果实产量、品质的直接因素”的假设，为果实争夺光合同化物能力提供直接证据。研究成果不仅可阐明源库关系对核桃光合同化产物的运转、分配及调节机制，还可为新疆早实核桃品种的优质丰产栽培提供科学依据和技术途径。

源库协调是果树高产高质的生理代谢基础，明确源库调节对果树产量、品质形成的生理影响对于深化高产高质生理生态理论和指导高产栽培具有重要的实践意义。新疆早实核桃品种为典型自然状态下存在多种源库比的果树。项目以新疆主栽品种‘新新2号’为试材，开展了不同叶果比对核桃 “源”（叶）光合同化物形成与装载、韧皮部“流”运输与同化物分配、“库”（果实）光合同化产物卸载与生长发育等具体实验内容，结果表明：（1）叶果比与碳水化合物同化的关系取决于叶果比的范围，叶果比在不同的范围内变动时对碳水化合同化产生的影响不同。极低的叶果比（叶果比=（1-2）:（2-3））条件下，光合作用的下调是叶片生长发育不良的结果；极高的叶果比（叶果比=（5）:（1-2））条件下，叶片光合作用的下调是光合末端产物反馈抑制和非气孔因素共同作用的结果。只有在合适的叶果比范围（叶果比=（3-4）:（1-2））内，源供应与库需求达到平衡状时，叶果比的改变对叶片光合作用无显著影响。（2）叶果比的改变会影响碳水化合物在源-库间的转运。果柄中碳水化合物的转运速率取决于叶片碳水化合物的同化能力和输出能力。低叶果比（叶果比=（1-2）:（2-3））条件下，碳水化合物的可用性较低，大部分碳水化合物被分配到果实中，果柄直径和长度的生长受限，在高叶果比（叶果比=（5）:（1-2））条件下，盈余的碳水化合物被分配到果柄中，利于果柄横向和纵向生长。（3）果实重量与叶果比呈正相关；低叶果比（叶果比=（1-2）:（2-3））下碳水化合物的可用性较低时，果实细胞有丝分裂减慢甚至提前停止，细胞生长也受到限制；叶果比的改变不会影响坚果中粗脂肪和粗蛋白的含量。（4）当叶果比大于2.02时，结果枝上碳水化合物的同化、转运和利用都可以达到较高水平；可以该指标进行疏果疏果。上述研究初步揭示了源库关系对核桃光合同化产物输配的影响，为新疆早实核桃主栽品种的优质丰产栽培提供了一定地科学依据和技术途径。