Mesophyll conductance in leaves of Japanese white birch (Betula platyphylla var. japonica) seedlings grown under elevated CO2 concentration and low N avialability
Mesophyll conductance in leaves of Japanese white birch (Betula platyphylla var. japonica) seedlings grown under elevated CO2 concentration and low N avialability
复制标题
高二氧化碳浓度和低氮肥供应条件下生长的日本白桦（Betula platyphylla var. japonica）幼苗叶肉导度
DOI：
10.1111/ppl.12335
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发表时间：
2015
影响因子：
6.4
通讯作者：
Kitao M，Yazaki K，Kitaoka S，Fukatsu E，Tobita H，Komatsu M，Maruyama Y，Koike T
中科院分区：
文献类型：
--
作者：
谷口 亨;小長谷賢一;栗田 学;Kitao M，Yazaki K，Kitaoka S，Fukatsu E，Tobita H，Komatsu M，Maruyama Y，Koike T
为了验证在高CO2浓度[CO2]下生长的植物叶片淀粉积累会降低叶肉电导（gm）的假设，我们研究了生长在环境和高CO2浓度[CO2]下的日本白桦的gmin幼苗，同时使用气体交换和叶绿素荧光测量。升高的[CO2]和有限的氮素供应都降低了基于面积的叶片氮，同时降低了叶绿体基质（Cc） CO2浓度下Rubisco羧化的最大速率（Vc,max）。相反，在不同的处理组合中，只有CO2浓度升高、氮素供应受限的幼苗叶片淀粉含量显著高于其他处理组合，而淀粉含量显著低于其他处理组合。然而，根据使用显微照片的叶片解剖分析，在不同的处理组合中，单位叶面积的叶绿体表面面向细胞间隙的面积没有显著差异。在有限氮条件下生长的植物细胞壁较厚，这是因为每面积叶质量的增加减去了非结构性碳水化合物。这些结果表明，在高[CO2]条件下生长的叶片中，淀粉积累和/或细胞壁变厚可能会阻碍CO2在叶绿体和细胞壁中的扩散，这可能是高[CO2]条件下光合作用下调以及与叶片N减少相关的Rubisco活性降低的另一个原因。
To test the hypothesis that mesophyll conductance (gm) would be reduced by leaf starch accumulation in plants grown under elevated CO2concentration [CO2], we investigated gmin seedlings of Japanese white birch grown under ambient and elevated [CO2] with an adequate and limited nitrogen supply using simultaneous gas exchange and chlorophyll fluorescence measurements. Both elevated [CO2] and limited nitrogen supply decreased area‐based leaf N accompanied with a decrease in the maximum rate of Rubisco carboxylation (Vc,max) on a CO2concentration at chloroplast stroma (Cc) basis. Conversely, only seedlings grown at elevated [CO2] under limited nitrogen supply had significantly higher leaf starch content with significantly lower gmamong the treatment combinations. Based on a leaf anatomical analysis using microscopic photographs, however, there were no significant difference in the area of chloroplast surfaces facing intercellular space per unit leaf area among treatment combinations. Thicker cell walls were suggested in plants grown under limited N by increases in leaf mass per area subtracting non‐structural carbohydrates. These results suggest that starch accumulation and/or thicker cell walls in the leaves grown at elevated [CO2] under limited N supply might hinder CO2diffusion in chloroplasts and cell walls, which would be an additional cause of photosynthetic downregulation as well as a reduction in Rubisco activity related to the reduced leaf N under elevated [CO2].