[CO2]升高对粮食作物影响的研究进展

自工业革命以来,由人类活动引起的大气CO_2浓度([CO_2])不断攀升,正驱动着全球气候变化,对全球农业产生重大影响。本文归纳总结了目前作物对高[CO_2]响应的主要研究技术手段,以及作物对高[CO_2]响应的机理研究,并进一步梳理了当前全球关于[CO_2]升高对作物产量和营养品质影响的研究。结果表明:相比封闭式或半封闭式环境控制试验系统,开放式试验系统(如开放式CO_2控制系统FACE)由于其能更加真实地模拟自然条件下作物对未来高[CO_2]的响应和适应情况,被公认为是目前研究作物对高[CO_2]响应的最理想手段。[CO_2]增高会增加C3作物光合速率、生物量和产量,在一定程度上缓解气候变化对农作物产生的负面影响,但是作物对大气[CO_2]的升高存在光合适应现象,当作物长期暴露在高[CO_2]条件下时,高[CO_2]对作物的促进作用会逐渐减缓。近10年的FACE试验发现,对高[CO_2]出现高应答的水稻品种,其光合速率和产量在高[CO_2]下的增加幅度比早期的主要粮食作物FACE试验结果平均高出两倍。此外,高[CO_2]会明显降低大部分非豆科C3作物中蛋白质和矿物质(如锌、铁)以及部分维生素的含量,加剧目前全球约2亿人由于维生素和矿物质元素等营养缺乏导致的健康问题。如何充分利用未来高[CO_2]实现高增产的同时,减缓粮食养分下降的负面影响,是迫切需要解决的科学问题。

Review on crop responses to rising atmospheric[CO2]

The concentration of CO₂ in the atmosphere([CO₂])has been continually increasing since the industrial revolution. The rising of[CO₂] has a great influence in agriculture and crops. In this paper, the main experimental methods studying the physiological and yield responses of crops to rising[CO₂] have been summarized. On the basis of reviewing the state of the art in this field, this paper indicates that the responses of crops to rising[CO₂] has been measured in green houses, closed or open top chambers and free-air CO₂ enrichment (FACE)platform. FACE enables growth of crops in large plots and avoids the alterations to the microclimate, thus it has been widely recognized as the gold standard for examining crop responses to elevated[CO₂]. Photosynthesis, biomass and yield of crops will benefit directly from an increase in[CO₂]. However, there is photosynthetic acclimation when crops are grown at elevated[CO₂] in the long-term. On the other hand, the rice FACE results indicated that some rice varieties show higher photosynthetic rate and larger yield responses to[CO 2] enrichment in the last decades.Recently, there has been growing awareness of the negative effects of rising[CO 2] on seed, grain and tuber quality, the protein and mineral content in the crops grown in the elevated[CO₂] conditions. A decrease of protein and mineral contents in crops due to elevated[CO₂] would exacerbate the mineral deficiencies which already exists. Thus, adapting crops to rising[CO₂] with larger grain yields and reduce the potential for already negative consequences of changes in food quality on human health is an urgent priority.