A Decrease in Mesophyll Conductance by Cell-Wall Thickening Contributes to Photosynthetic Downregulation1
A Decrease in Mesophyll Conductance by Cell-Wall Thickening Contributes to Photosynthetic Downregulation1
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DOI：
10.1104/pp.20.00328
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发表时间：
2020-08-01
期刊：
影响因子：
7.4
通讯作者：
Evans, John R.
中科院分区：
文献类型：
--
作者：
Sugiura, Daisuke;Terashima, Ichiro;Evans, John R.
人们一直认为，非结构性碳水化合物的积累引发Rubisco含量的降低，从而下调光合作用。然而，在一些植物物种中，库源比的降低导致光合作用的减少，结构和非结构碳水化合物含量的增加。在这里，我们测试了细胞壁材料的增加，而不是淀粉含量的增加，是否通过降低叶肉导度直接影响光合作用。对高氮和低氮条件下生长的大豆（Glycine max）和法国豆（Phaseolus vulgaris）初生叶的形态、解剖和生理性状进行了测定。我们在播种后2周去除其他叶片以降低库源比，并在落叶后0、1和2周进行测量。大豆和豆荚的胞源比降低后，叶肉导度降低的原因不是淀粉积累，而是细胞壁增厚。
It has been argued that accumulation of nonstructural carbohydrates triggers a decrease in Rubisco content, which downregulates photosynthesis. However, a decrease in the sink-source ratio in several plant species leads to a decrease in photosynthesis and increases in both structural and nonstructural carbohydrate content. Here, we tested whether increases in cell-wall materials, rather than starch content, impact directly on photosynthesis by decreasing mesophyll conductance. We measured various morphological, anatomical, and physiological traits in primary leaves of soybean (Glycine max) and French bean (Phaseolus vulgaris) grown under high- or low-nitrogen conditions. We removed other leaves 2 weeks after sowing to decrease the sink-source ratio and conducted measurements 0, 1, and 2 weeks after defoliation.Cell-wall thickening, rather than starch accumulation, leads to a decrease in mesophyll conductance after a reduction in the sink-source ratio in soybean and French bean.