Suppression of starch accumulation in ‘sugar leaves’ of rice affects plant productivity under field conditions
Suppression of starch accumulation in ‘sugar leaves’ of rice affects plant productivity under field conditions
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DOI：
10.1080/1343943x.2016.1259958
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发表时间：
2017-01
影响因子：
2.5
通讯作者：
Masaki Okamura;T. Hirose;Yoichi Hashida;R. Ohsugi;N. Aoki
中科院分区：
文献类型：
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作者：
Masaki Okamura;T. Hirose;Yoichi Hashida;R. Ohsugi;N. Aoki
许多植物在白天将大部分光合产物以淀粉的形式积累，而有些植物则积累蔗糖。虽然这些高蔗糖叶的存在，称为“糖叶”，早已知道，糖叶相比，“淀粉叶”的生理特性仍然不清楚。本研究以一个叶片淀粉合成受到抑制的突变体为材料，研究了具有典型糖叶的水稻淀粉积累的生理作用。当在光照强度为400 μmol m−2 s−1的受控条件下生长时，突变体的初始生长与野生型植物相似，即使在6 h光照/18 h黑暗的光周期中，生长所需的碳资源在夜间也是如此。这一发现表明水稻在夜间不依赖叶淀粉作为碳源。相比之下，在田间条件下，突变体的籽粒产量显着低于野生型只有当植物在成熟期暴露于充分的阳光。这些结果可能表明，糖叶中的淀粉积累在充足的光照条件下维持高源容量中起着重要作用，而不是作为植物夜间生长的碳源。
Abstract While many plants accumulate the majority of their photoassmilates as starch during the daytime, some plants accumulate sucrose. Although the existence of these high-sucrose leaves, called ‘sugar leaves’, has long been known, the physiological characteristics of sugar leaves compared to ‘starch leaves’ remain unclear. In this study, the physiological roles of starch accumulation in rice, which has typical sugar leaves, were investigated using a mutant with suppressed leaf-starch biosynthesis. When grown under controlled conditions with light intensity of 400 μmol m−2 s−1, the initial growth of the mutant was similar to that of the wild-type plant, even with a 6-h-light/18-h-dark photoperiod in which carbon resources for growth are required during the night. This finding indicates that rice does not rely on leaf starch as a carbon resource during the night. By contrast, under field conditions, the grain yields of the mutant were significantly lower than those of the wild type only when the plants were exposed to full sunlight during the ripening period. These results may indicate that starch accumulation in sugar leaves plays an important role in maintaining a high source capacity under sufficient light conditions rather than as a carbon resource for the plant’s growth at night.