Geiger D R, Ploeger B J, Fox T C, Fondy B R
Department of Biology, University of Dayton, Dayton, Ohio 45469.
Plant Physiol. 1983 Aug;72(4):964-70. doi: 10.1104/pp.72.4.964.
A search for source leaf sucrose pools that differed in their relation to export was carried out in photosynthesizing leaves of Beta vulgaris L. The time course of depletion of [(14)C]sucrose in a leaf in unlabeled CO(2) following steady state labeling provided evidence for two distinct sucrose pools. After the start of the light period, leaf blade sucrose remained constant although it exchanged between the two pools. Newly synthesized sucrose destined for export passed through one pool more rapidly than through the other. All of the leaf blade sucrose appeared to exchange with export sucrose. Modeling and regression analysis of [(14)C]sucrose data provided a means for estimating the size of the two pools. From 20 to 40% of the sucrose was calculated to be present in the pool that provided the less direct path to export; this was likely vacuolar sucrose. The remainder of the sucrose in the blade was probably in the cytoplasm and veins. Added amounts of leaf blade sucrose, produced in response to elevated CO(2), appeared to be stored mainly in the vacuolar compartment.
在甜菜（Beta vulgaris L.）的光合叶片中，对与输出相关的源叶蔗糖库进行了研究。在稳态标记后，未标记CO₂条件下叶片中[(14)C]蔗糖消耗的时间进程为两个不同的蔗糖库提供了证据。光照期开始后，叶片蔗糖保持恒定，尽管它在两个库之间交换。新合成的用于输出的蔗糖通过一个库的速度比通过另一个库的速度更快。所有叶片蔗糖似乎都与输出蔗糖进行交换。[(14)C]蔗糖数据的建模和回归分析提供了一种估计两个库大小的方法。据计算，20%至40%的蔗糖存在于提供输出间接途径较少的库中；这可能是液泡蔗糖。叶片中其余的蔗糖可能存在于细胞质和叶脉中。响应于升高的CO₂而产生的额外叶片蔗糖量似乎主要储存在液泡区室中。
