Studies on sink activity-controlling mechanisms in sweet potato production.

库活性的遗传改良是甘薯产量大幅度提高的关键。本试验旨在探讨内源注射蔗糖溶液对提高根系淀粉合成过程中相关酶活性，提高根系生产力的作用。注射葡萄糖和果糖溶液也有效。利用该补助金购买的碳分析仪，调查了注入的糖或碳在植物器官中的分布<13>。本研究从库源关系的角度认识到，糖浓度的增加是提高酶活性和库器官活性的触发器，从而引起叶片光合作用的增强，最终导致根系淀粉产量的增加。这一发现为分析甘薯库源关系提供了一个新的视角，也为甘薯等作物酶活性的生理和遗传调控提供了基础信息。

It has been known that the genetic improvement of sink activity is essential to get a large enhancement of sweet potato yield. The endogenous injection of sucrose solution into plants was tried here to elucidate the effect on increasing the activity of enzymes such as AGPase included in starch synthesis process in roots and improving root productivity. The injections of glucose and fructose solutions were also effective. The distribution of injected sugar or carbon to plant organs was surveyed using a ^<13>C analyzer purchased by this grant-in-aid. This survey gave such an understanding in sink-source relationship that the increase of sugar concentration became a trigger to increase the activity of enzyme and sink organ, and this caused an increase in leaf photosynthesis with a final result of increase of starch production in roots. This finding may indicate a new viewpoint in the analysis of sink-source relationship and provide fundamental information in physiological and genetic control of enzyme activity in sweet potato and other many crops.