Regulation of Diurnal Carbohydrate Reserves and Translocation

白天的碳水化合物储备为叶片提供夜间和低光合作用期间出口的碳，从而维持对非光合作用植物结构的碳的不间断供应，以供生长、储存和新陈代谢。在一些植物中，如甜菜和大豆，每日储存的蔗糖以淀粉的形式存在，而在其他植物，如蚕豆和菠菜中，蔗糖积累。我们计划的目标是系统地确定(1)如何以一种向叶片提供每日碳水化合物储备的方式来调控蔗糖和淀粉的碳分配以及一起出口的碳出口，以及(2)当出口受到限制或光合作用增加时，光合作用碳同化、碳分配和出口如何相互作用。无论是积累蔗糖的植物还是不积累蔗糖的植物。我们将通过延长白天或缩短前一晚的碳分配来测量这两种植物叶片的出口速率、酶活性和代谢物水平的变化。在贮藏蔗糖和储存淀粉的植物中，将比较低温导致接受器官新陈代谢减慢或通过增加二氧化碳提高光合作用而限制出口对光合作用和碳水化合物积累的影响。

Diurnal carbohydrate reserves provide leaves with carbon for export at night and during times of low photosynthesis, thereby maintaining an uninterrupted supply of carbon to non- photosynthesizing plant structures for growth, storage and metabolism. In some plants, like sugar beet and soybean, the diurnal reserve takes the form of starch, while in other plants, like fava bean and spinach, sucrose accumulates. The objectives of our program are to identify systematically (1) how carbon apportionment to sucrose and starch and of export together are regulated in a way that furnishes a diurnal carbohydrate reserve to leaves and regulates the current rate of export throughout the day- night cycle and (2) how photosynthetic carbon assimilation, carbon allocation and export interact when export is restricted or photosynthesis is increased, both in plants that accumulate sucrose and those that do not. We will measure changes in export rates, enzyme activities and metabolite levels in leaves of the two types of plants when carbon allocation is changed by extending the day or shortening the previous night. The ways in which restricting export by chilling-induced slowing of metabolism in the receiving organs or of increasing photosynthesis by raising CO2 affects photosynthesis and carbohydrate accumulation will be compared in sucrose-storing and starch storing plants.