Reduction of transpiration and altered nutrient allocation contribute to nutrient decline of crops grown in elevated CO2 concentrations
Reduction of transpiration and altered nutrient allocation contribute to nutrient decline of crops grown in elevated CO2 concentrations
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DOI：
10.1111/pce.12007
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发表时间：
2013-03-01
影响因子：
7.3
通讯作者：
Lobell, David B.
中科院分区：
文献类型：
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作者：
McGrath, Justin M.;Lobell, David B.
与生长在环境[CO2]中的植物相比，生长在高[CO2]中的植物具有较低的蛋白质和矿物质浓度。碳水化合物产量增加导致的稀释是一个可能的原因，但它不能解释所有的减少。两个提出的，但未经检验的假设是：（1）减少冠层蒸腾减少营养物质流到根，从而减少营养吸收和（2）生理变化引起的代谢物或酶浓度的变化改变蛋白质辅因子或其他有机复合物中的矿物质的需求，转移组织之间的分配，并可能改变吸收。在这里，我们使用以前的研究在作物的荟萃分析来验证这些假设。营养物质获得的质量流下降显着增加[CO2]比营养物质通过土壤扩散到根部，支持第一个假设。同样，Mg在叶和小麦茎中的浓度下降幅度较大，但在其他组织中的下降幅度较小。由于叶绿素需要大部分的植物总镁，叶绿素浓度降低生长在升高[CO2]，这支持了第二个假设。了解这些机制可以指导改善营养物质含量的努力，并允许在未来气候变化情景下模拟营养物质变化和健康影响。
Plants grown in elevated [CO2] have lower protein and mineral concentrations compared with plants grown in ambient [CO2]. Dilution by enhanced production of carbohydrates is a likely cause, but it cannot explain all of the reductions. Two proposed, but untested, hypotheses are that (1) reduced canopy transpiration reduces mass flow of nutrients to the roots thus reducing nutrient uptake and (2) changes in metabolite or enzyme concentrations caused by physiological changes alter requirements for minerals as protein cofactors or in other organic complexes, shifting allocation between tissues and possibly altering uptake. Here, we use the meta-analysis of previous studies in crops to test these hypotheses. Nutrients acquired mostly by mass flow were decreased significantly more by elevated [CO2] than nutrients acquired by diffusion to the roots through the soil, supporting the first hypothesis. Similarly, Mg showed large concentration declines in leaves and wheat stems, but smaller decreases in other tissues. Because chlorophyll requires a large fraction of total plant Mg, and chlorophyll concentration is reduced by growth in elevated [CO2], this supports the second hypothesis. Understanding these mechanisms may guide efforts to improve nutrient content, and allow modeling of nutrient changes and health impacts under future climate change scenarios.