The rate-limiting step for CO(2) assimilation at different temperatures is influenced by the leaf nitrogen content in several C(3) crop species.
The rate-limiting step for CO(2) assimilation at different temperatures is influenced by the leaf nitrogen content in several C(3) crop species.
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DOI：
10.1111/j.1365-3040.2011.02280.x
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发表时间：
2011-05
期刊：
影响因子：
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通讯作者：
W. Yamori;T. Nagai;A. Makino
中科院分区：
文献类型：
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作者：
W. Yamori;T. Nagai;A. Makino
在不同叶片温度下，在380µmol mol(-1) CO(2)浓度（A(380)）下，氮(N)供应对CO(2)同化速率(A)的限制步长(A)的影响在几种作物中进行了研究，因为氮营养改变了光合组分之间的氮分配。叶片N、核酮糖1·5-二磷酸羧化酶/加氧酶（Rubisco）和细胞色素f （cyt f）含量随氮供给的增加而增加，但cyt f/Rubisco比值降低。高叶片氮含量与高气孔（g(s)）和叶肉导度（g(m)）有关，但由于g(s)和g(m)的增加不足以补偿a（380）的变化，导致细胞间（C(i)）和叶绿体CO(2)浓度（C(C)）降低。利用A-C(c)响应来估计RuBP羧基化的最大速率（V(cmax)）和叶绿体电子传递（J(max)）。J(max) /V（cmax）比值随叶片氮含量的降低而降低，这与cyt f/Rubisco比值的结果一致。利用C(3)光合作用模型分析表明，在低N浓度生长的植株中，A（380）倾向于受到RuBP羧化的限制，而在高N浓度生长的植株中，A（380）则受到RuBP再生的限制。我们得出结论，A（380）的限制步骤取决于叶片N含量，主要由Rubisco和电子传递组分之间的N分配决定。
Effects of nitrogen (N) supply on the limiting step of CO(2) assimilation rate (A) at 380 µmol mol(-1) CO(2) concentration (A(380) ) at several leaf temperatures were studied in several crops, since N nutrition alters N allocation between photosynthetic components. Contents of leaf N, ribulose 1·5-bisphosphate carboxylase/oxygenase (Rubisco) and cytochrome f (cyt f) increased with increasing N supply, but the cyt f/Rubisco ratio decreased. Large leaf N content was linked to a high stomatal (g(s) ) and mesophyll conductance (g(m) ), but resulted in a lower intercellular (C(i) ) and chloroplast CO(2) concentration (C(c) ) because the increase in g(s) and g(m) was insufficient to compensate for change in A(380) . The A-C(c) response was used to estimate the maximum rate of RuBP carboxylation (V(cmax) ) and chloroplast electron transport (J(max) ). The J(max) /V(cmax) ratio decreased with reductions in leaf N content, which was consistent with the results of the cyt f/Rubisco ratio. Analysis using the C(3) photosynthesis model indicated that A(380) tended to be limited by RuBP carboxylation in plants grown at low N concentration, whereas it was limited by RuBP regeneration in plants grown at high N concentration. We conclude that the limiting step of A(380) depends on leaf N content and is mainly determined by N partitioning between Rubisco and electron transport components.