The Rockefeller University, 10021, New York, N.Y., USA.
Planta. 1973 Jun;113(2):179-91. doi: 10.1007/BF00388202.
The capacity of a growing leaf blade of Cucurbita pepo L. to import (14)C-labelled photoassimilate is lost in a basipetal direction. Import into the lamina tip stops when the blade is 10% expanded. Development of the leaf progresses linearly with time and the lamina base stops importing when the blade is 45% expanded. Export capacity also develops basipetally and follows immediately the loss of import capacity, at least in the lamina base. The small amount of material initially exported from the leaf tip is redistributed to the still-importing leaf base, delaying export from the lamina until the blade is 35% expanded. Loss of import capacity by the petiole is both basipetal and dorsoventral. The proximal, adaxial portion of the petiole is the last region to cease importing (14)C. Leaves of Beta vulgaris L. and Nicotiana tabacum L. also lose import capacity in a basipetal direction.
蔓生南瓜叶片的同化产物输入能力沿基轴方向丧失。当叶片展开 10%时，叶尖的导入停止。叶片的发育随时间呈线性进展，当叶片展开 45%时，叶基停止导入。导出能力也沿基轴方向发育，并在导入能力丧失后立即发生，至少在叶基中是这样。最初从叶尖输出的少量物质被重新分配到仍在导入的叶基，从而延迟了叶片的输出，直到叶片展开 35%。叶柄的导入能力丧失也是沿基轴和背腹轴方向发生的。叶柄的近轴、腹侧部分是最后停止导入 (14)C 的区域。菠菜和烟草的叶片也沿基轴方向丧失导入能力。
