CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants
CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants
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DOI：
10.1890/11-0485.1
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发表时间：
2012-02-01
期刊：
影响因子：
4.8
通讯作者：
Carlisle, Eli A.
中科院分区：
文献类型：
--
作者：
Bloom, Arnold J.;Rubio-Asensio, Jose Salvador;Carlisle, Eli A.
地球大气中的二氧化碳浓度在本世纪可能会增加一倍。植物对这种增加的反应强烈地依赖于它们的氮状况，但原因尚不确定。在这里，我们评估了通过拍摄CO2和O-2通量的转变，当植物收到硝酸盐，而不是铵作为氮源（三角洲AQ）的地上硝酸盐同化成氨基酸。芽硝酸盐同化成为可以忽略不计，增加CO2在一个分类上不同的组的8个C-3植物物种，是相对不敏感的CO2在3个C-4物种，并表现出中间的敏感性在两个C-3-C-4中间物种。然后，我们研究了CO2水平和铵与硝酸盐营养对生长的影响，在鲜质量的变化方面进行评估，几个C-3物种和景天科酸代谢（CAM）物种。升高的CO2（720 μ mol CO2/mol的所有气体存在）刺激生长或没有影响，在五个C-3物种测试时，他们收到铵作为氮源，但抑制生长或没有影响，如果他们收到硝酸盐。在硝酸盐，两个C-3物种生长速度在低于环境（类似于310 μ mol/mol）比升高的CO2。CAM种生长速度比升高或亚环境CO2下铵或硝酸盐营养在环境中。这项研究表明，CO2富集抑制了各种C-3植物的地上部硝酸盐同化，这种现象可能对它们的生长产生深远的影响。这表明地上部硝酸盐同化对整个C-3植物的硝酸盐同化有重要贡献。因此，上升的CO2及其对地上部硝酸盐同化的影响可能会影响C-3植物物种的分布。
The CO2 concentration in Earth's atmosphere may double during this century. Plant responses to such an increase depend strongly on their nitrogen status, but the reasons have been uncertain. Here, we assessed shoot nitrate assimilation into amino acids via the shift in shoot CO2 and O-2 fluxes when plants received nitrate instead of ammonium as a nitrogen source (Delta AQ). Shoot nitrate assimilation became negligible with increasing CO2 in a taxonomically diverse group of eight C-3 plant species, was relatively insensitive to CO2 in three C-4 species, and showed an intermediate sensitivity in two C-3-C-4 intermediate species. We then examined the influence of CO2 level and ammonium vs. nitrate nutrition on growth, assessed in terms of changes in fresh mass, of several C-3 species and a Crassulacean acid metabolism (CAM) species. Elevated CO2 (720 mu mol CO2/mol of all gases present) stimulated growth or had no effect in the five C-3 species tested when they received ammonium as a nitrogen source but inhibited growth or had no effect if they received nitrate. Under nitrate, two C-3 species grew faster at sub-ambient (similar to 310 mu mol/mol) than elevated CO2. A CAM species grew faster at ambient than elevated or sub-ambient CO2 under either ammonium or nitrate nutrition. This study establishes that CO2 enrichment inhibits shoot nitrate assimilation in a wide variety of C-3 plants and that this phenomenon can have a profound effect on their growth. This indicates that shoot nitrate assimilation provides an important contribution to the nitrate assimilation of an entire C-3 plant. Thus, rising CO2 and its effects on shoot nitrate assimilation may influence the distribution of C-3 plant species.