Research Institute for Photosynthesis, Department of Botany, University of Sheffield, S10 2TN, Sheffield, UK.
Planta. 1985 May;164(2):172-8. doi: 10.1007/BF00396079.
The incorporation of (14)C into sucrose and hexose phosphates during steady-state photosynthesis was examined in intact leaves of Zea mays L. plants. The compartmentation of sucrose synthesis between the bundle sheath and mesophyll cells was determined by the rapid fractionation of the mesophyll and comparison of the labelled sucrose in this compartment with that in a complete leaf after homogenisation. From these experiments it was concluded that the majority of sucrose synthesis occurred in the mesophyll cell type (almost 100% when the time-course of sucrose synthesis was extrapolated to the time of (14)C-pulsing). The distribution of enzymes involved in sucrose synthesis between the two cell types indicated that sucrose-phosphate synthetase was predominantly located in the mesophyll, as was cytosolic (neutral) fructose-1,6-bisphosphatase activity. Stromal (alkaline) fructose-1,6-bisphosphatase activity was found almost exclusively in the bundle-sheath cells. No starch was found in the mesophyll tissue. These data indicate that in Zea mays starch and sucrose synthesis are spatially, separated with sucrose synthesis occurring in the mesophyll compartment and starch synthesis in the bundle sheath.
在玉米（Zea mays L.）植株完整叶片中研究了稳态光合作用过程中（14）C 掺入蔗糖和己糖磷酸中的情况。通过快速分离叶肉组织并比较均质化后完整叶片中标记的蔗糖与该组织中标记的蔗糖，确定了蔗糖合成在鞘细胞和叶肉细胞之间的区室化。从这些实验中得出结论，大多数蔗糖合成发生在叶肉细胞类型中（当将蔗糖合成的时间过程外推到（14）C 脉冲时间时，几乎为 100%）。参与蔗糖合成的酶在这两种细胞类型之间的分布表明，蔗糖磷酸合成酶主要位于叶肉细胞中，胞质（中性）果糖-1,6-二磷酸酶活性也是如此。基质（碱性）果糖-1,6-二磷酸酶活性几乎仅存在于鞘细胞中。在叶肉组织中未发现淀粉。这些数据表明，在玉米中，淀粉和蔗糖的合成在空间上是分开的，蔗糖合成发生在叶肉区室中，淀粉合成发生在鞘细胞中。
