Structural and physiological responses of the C4 grass Sorghum bicolor to nitrogen limitation.
Structural and physiological responses of the C4 grass Sorghum bicolor to nitrogen limitation.
复制标题
C4 草高粱对氮限制的结构和生理反应。
DOI：
10.1080/1343943x.2018.1432290
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发表时间：
2018
影响因子：
2.5
通讯作者：
Ueno O
中科院分区：
文献类型：
--
作者：
2. Makino Y;Ueno O
氮是影响C3植物和C4植物光合作用和生产力的主要营养元素之一。C4光合作用是通过叶肉细胞和维管束鞘细胞之间的密切协调进行的。然而，如何在氮限制下调控C4植物叶片的结构和生理性状的发展仍然不清楚。研究了NADP-ME型C4禾草二色高粱叶片对氮限制的结构和生理响应。植物在四种氮供应水平下生长（每5升盆0.05至0.6克氮）。降低供氮水平导致净光合速率、气孔导度、叶片氮含量、叶绿素含量、磷酸烯醇式丙酮酸羧化酶/核酮糖1，5-二磷酸羧化酶/加氧酶活性比值降低，δ 13 C值和光合氮利用效率升高。低氮处理叶片较薄，光合细胞较小，尤其是M，导致M/BS组织面积比较低，叶绿体较小且较少。低氮胁迫下叶片中BS叶绿体积累了丰富的淀粉粒。每个基粒堆的类囊体的数量减少M叶绿体，但不是在BS叶绿体。低氮处理叶片的细胞壁较厚，尤其是BS细胞，这可能与BS细胞中δ 13 C负值较少和胞间连丝较少有关。这些数据揭示了C4植物对氮限制的结构和生理响应，其中大部分与氮限制下的细胞氮分配、光利用、CO2扩散和泄漏以及代谢物运输有关。
Nitrogen (N) is one of the major nutrients influencing photosynthesis and productivity of C4plants as well as C3plants. C4photosynthesis operates through close coordination between mesophyll (M) and bundle sheath (BS) cells. However, how the development of structural and physiological traits in leaves of C4plants is regulated under N limitation remains uncertain. We investigated structural and physiological responses of leaves of the NADP-ME-type C4grassSorghum bicolorto N limitation. Plants were grown under four levels of N supply (.05 to .6 g N per 5-L pot). Decreasing N supply resulted in decreases in net photosynthetic rate, stomatal conductance, leaf N and chlorophyll contents, and the activity ratio of phosphoenolpyruvate carboxylase to ribulose 1,5-bisphosphate carboxylase/oxygenase and increases in δ13C values and photosynthetic N use efficiency. Low-N leaves were thinner and had smaller photosynthetic cells, especially in M, resulting in lower M/BS tissue area ratio, and contained smaller and fewer chloroplasts. The BS chloroplasts in the low-N leaves accumulated abundant starch grains. The number of thylakoids per granal stack was reduced in M chloroplasts but not in BS chloroplasts. The low-N leaves had thicker cell walls, especially in the BS cells, which might be associated with less negative δ13C values, and fewer plasmodesmata in the BS cells. These data reveal structural and physiological responses of C4plants to N limitation, most of which would be related to cellular N allocation, light use, CO2diffusion and leakiness, and metabolite transport under N limitation.