开放式空气中CO_2浓度增高(FACE)对水稻生长和发育的影响

人类活动导致的大气和气候变化将极大地改变作物的生长环境,其中最大的一个变化就是大气二氧化碳(CO2)浓度的迅速上升:从工业革命前的平均270μmol/mol上升到目前的381μmol/mol,到2050年至少超过550μmol/mol。FACE(Free-air CO2 enrichment,开放式空气中CO2浓度增高)试验是目前评估未来高浓度CO2对作物生长和产量实际影响的最佳方法。水稻无疑是人类最重要的食物来源,迄今为止人类利用FACE技术开展水稻响应和适应的研究已有10a(19982008年)的历史。以生长发育为主线,首次系统综述了10a水稻FACE试验在该领域的研究成果,总结了FACE情形下高浓度CO2(模拟本世纪中叶大气CO2浓度)对主要供试水稻品种(小区面积大于4m2)光合作用、生育进程、地上部生长、地下部生长、物质分配、籽粒灌浆、产量构成以及倒伏性状等影响的研究进展,比较了FACE与非FACE研究之间以及中国和日本FACE研究(世界上唯一的两个大型水稻FACE研究)之间的异同点。根据研究进展以及当前的技术水平,文章最后提出了该领域的3个优先课题:(1)FACE情形下杂交稻生产力响应高于预期的生物学机制;(2)FACE情形下CO2与主要栽培措施的互作效应;(3)FACE情形下CO2与主要空气污染物臭氧的互作效应。这些响应的机理性解析将有助于从根本上减少人类预测未来粮食安全的不确定性,进而更加有效地制订出应对全球变化的适应策略。

What have we learned from 10 years of free\|air CO2 enrichment (FACE) experiments on rice? Growth and development

Human activities are causing rapid changes in the atmosphere and climate that alter many dements of the future crop production environment.Foremost among these changes is the increasing atmospheric carbon dioxide concentration (CO2]),which averaged about 270 μmol/mol prior to the industrial revolution,have now surpassed 381 μmol/mol,and will exceed 550 μmol/mol by 2050.Free-air CO_2 enrichment (FACE) experiments currently provide the most realistic measure of the future impact of elevated CO_2] on yield and growth crops.Rice (Oryza sativa L.) is unarguably the most important food source in the world.It has been 10 years (1998-2008) since the first FACE project was set up to investigate the response and adaptation of rice to elevated CO_2].The present review summarizes the evidence from 10-year FACE experiments on the growth and development of rice,mainly focuses on the effects of FACE treatment (elevated CO_2] anticipated for the middle of this century) on the photosynthesis,phenology,aboveground growth,underground growth,dry matter allocation,grain filling,field components and lodging traits of main tested cultivars (the planting area of each plot was no less than 4 m~2),compares the similarities and differences in research results obtained from FACE and non-FACE experiments and obtained at two experimental sites (i.e.,Japan and China:only two large-scale rice FACE experiments in the world).Based on the current state of knowledge and technological advances,three priority areas for future FACE research on rice are presented as follows: (1) Biological mechanisms for higher-than-expected productivity stimulation of hybrid rice cultivars with FACE: (2) Interactions between elevated CO_2] and main crop technologies on rice under fully open air conditions: (3) Interactions between elevated CO_2] and ozone (a major air pollutant) concentration on rice under fully open-air conditions.Mechanistic understanding of these responses could help in reducing uncertainties in projections of future global food security,and develop more effective adaptation strategies under the anticipated global changes.