National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602, Japan.
Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan.
Plant Sci. 2016 Jan;242:270-277. doi: 10.1016/j.plantsci.2015.08.014. Epub 2015 Aug 28.
Dry matter production of crops is determined by how much light they intercept and how efficiently they use it for carbon fixation; i.e., photosynthesis. The high-yielding rice cultivar, Akenohoshi, maintains a high photosynthetic rate in the middle of the day owing to its high hydraulic conductance in comparison with the elite commercial rice cultivar, Koshihikari. We developed 94 recombinant inbred lines derived from Akenohoshi and Koshihikari and measured their exudation rate to calculate hydraulic conductance to osmotic water transport in a paddy field. A quantitative trait locus (QTL) for exudation rate was detected on the long arm of chromosome 2 at the heading and ripening stages. We developed chromosome segment substitution lines which carried Akenohoshi segments in the Koshihikari genetic background, and measured hydraulic conductance to both osmotic and passive water transport. The QTL was confirmed to be located within a region of about 4.2Mbp on the distal end of long arm of chromosome 2. The Akenohoshi allele increased root surface area and hydraulic conductance, but didn't increase hydraulic conductivity of a plant.
作物的干物质产量取决于它们截获的光量以及它们将其用于碳固定（即光合作用）的效率。高产水稻品种“秋明”与优质商业水稻品种“越光”相比，具有较高的水力导度，因此在中午能够保持较高的光合速率。我们开发了 94 个源自“秋明”和“越光”的重组自交系，并测量了它们的渗出率，以计算稻田中渗透水运输的水力导度。在抽穗和成熟阶段，在第 2 号染色体的长臂上检测到渗出率的数量性状位点（QTL）。我们开发了携带“秋明”片段的“越光”遗传背景的染色体片段代换系，并测量了对渗透和被动水运输的水力导度。该 QTL 被确认为位于第 2 号染色体长臂末端约 4.2Mbp 的区域内。“秋明”等位基因增加了根表面积和水力导度，但没有增加植物的水力传导率。
