气候变化对作物矿质元素利用率影响研究进展

作物矿质元素利用率对气候变化的响应是目前全球变化研究中既重要、又复杂,且认知最少的科学领域。这个科学问题的研究关系到解密或预测陆地植物及农作物矿质胁迫对全球气候变化响应的机理,为将来农业投入提供理论依据,是应对气候变化的当务之急。目前只有少数研究,通过模拟试验,探索性地开展了CO_2浓度或温度升高的环境条件下,矿质元素在土壤-植物系统迁移、分布和储存特征的研究。从相关的文献报道来看,CO_2浓度升高环境条件下,小麦和水稻作物籽粒中大量和痕量元素的富集水平一般呈下降趋势。但温度升高情况下,作物各器官对对矿质元素的吸收情况则更为复杂。正由于气候因素与植物矿质元素利用率之间关系的复杂性,在气候变化背景下,解密作物矿质胁迫对全球气候变化响应的科学问题,尚需改进试验方法、手段,从土壤性质、作物生态生理,以及农业生态系统中矿质元素在土壤-作物系统中迁移转化的过程,全面考察作物矿质元素利用率对气候变化的响应机理。

State-of-the-art review of the impact of climatic change on bioavailability of mineral elements in crops

We critically review the current state of understanding of how bioaccumulation and bioavailability of trace elements in crops might be affected by global warming and elevated CO₂ concentrations, and the interaction of different environmental processes in controlling the transfer, distribution and deposition of mineral elements in crops in a changing environment. The 4^th IPCC Assessment report concludes that global climate change is occurring due to human activities and will have a significant impact on the earth's natural systems. However, significant uncertainty over the likely magnitude of these changes and their impacts exists. While bioaccumulation of mineral elements in crops is recognized as a physiologically important process, and is affected by several different climate variables (e.g. temperature, CO₂), we know little about how these variables interact with other climate variables affecting plant productivity (e.g. rainfall), and how mineral stresses at the individual plant level translate to impacts at the agroecosystem level. Several studies of crop plants grown at high root temperatures found higher uptakes of zinc, lead, cadmium, silver, chromium and antimony versus plants grown at low root temperatures. Numerous studies report that elevated CO₂ concentrations generally decreased the accumulation of mineral elements in spring wheat and rice. However, the vast majority of past research has focused on the isolated effects of elevated CO₂ concentrations and temperature rise on crop productivity. We still know relatively little about the influence of temperature raising and elevated CO₂ concentrations on plant and mineral element interactions in a changing environment, making it very difficult to predict how food production will respond to future climate change. Furthermore, although we have a fairly good understanding of how mineral concentrations in plant tissue can affect herbivores, we know comparatively little about these effects influence pasture production. There is clear need to integrate our current understanding from quantitative experimental studies within process-based models of plant productivity that should include interactions among climate, mineral stress and herbivory in order to better predict the responses of crops and pastures to future global climate change.