Haworth Matthew, Moser Gerald, Raschi Antonio, Kammann Claudia, Grünhage Ludger, Müller Christoph
Consiglio Nazionale delle Ricerche - Istituto di Biometeorologia, Via Giovanni Caproni 8, 50145 Florence, Italy.
Department of Plant Ecology, Interdisciplinary Research Centre, University of Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany.
Funct Plant Biol. 2015 Feb;43(1):26-39. doi: 10.1071/FP15232.
The rising concentration of carbon dioxide in the atmosphere ([CO2]) has a direct effect on terrestrial vegetation through shifts in the rates of photosynthetic carbon uptake and transpirational water-loss. Free Air CO2 Enrichment (FACE) experiments aim to predict the likely responses of plants to increased [CO2] under normal climatic conditions. The Giessen FACE system operates a lower [CO2] enrichment regime (480μmolmol-1) than standard FACE (550-600μmolmol-1), permitting the analysis of a mixed species temperate meadow under a [CO2] level equivalent to that predicted in 25-30 years. We analysed the physiological and morphological responses of six species to investigate the effect of moderate [CO2] on spring biomass production. Carbon dioxide enrichment stimulated leaf photosynthetic rates and supressed respiration, contributing to enhanced net assimilation and a 23% increase in biomass. The capacity for photosynthetic assimilation was unaffected by [CO2] enrichment, with no downregulation of rates of carboxylation of Rubisco or regeneration of ribulose-1,5-bisphosphate. Foliar N content was also not influenced by increased [CO2]. Enhanced [CO2] reduced stomatal size, but stomatal density and leaf area index remained constant, suggesting that the effect on gas exchange was minimal.
大气中二氧化碳浓度（[CO₂]）的上升通过光合碳吸收速率和蒸腾失水速率的变化对陆地植被产生直接影响。自由空气二氧化碳富集（FACE）实验旨在预测在正常气候条件下植物对升高的[CO₂]的可能反应。吉森FACE系统运行的[CO₂]富集水平（480μmol/mol）低于标准FACE（550 - 600μmol/mol），从而能够在相当于25至30年后预测水平的[CO₂]浓度下分析一个混合物种的温带草甸。我们分析了六个物种的生理和形态反应，以研究适度升高的[CO₂]对春季生物量生产的影响。二氧化碳富集刺激了叶片光合速率并抑制了呼吸作用，有助于提高净同化作用并使生物量增加23%。光合同化能力不受[CO₂]富集的影响，羧化酶Rubisco的羧化速率或核酮糖-1,5-二磷酸的再生速率均未下调。叶片氮含量也不受升高的[CO₂]影响。升高的[CO₂]减小了气孔大小，但气孔密度和叶面积指数保持不变，这表明对气体交换的影响很小。
