CO2浓度升高对玉米叶片光合生理特性的影响

以沈糯3号为研究材料，利用开顶式气室(OTCs)法研究了二氧化碳(CO₂)浓度升高处理下，玉米叶片叶绿素含量、光合生理特性及其子粒产量的变化，揭示CO₂浓度升高对玉米光合生理特性及子粒产量的影响机理。结果表明，在整个生育期内，与对照相比，高浓度CO₂处理下，玉米叶片叶绿素a、叶绿素b及叶绿素(a+b)的含量增加，而叶绿素a/b的值则先升高后降低；在整个处理期间，净光合速率均高于对照(p>0.05)，升高幅度为12.6%～71.1%，气孔导度低于对照(p>0.05)，其降低幅度为2.9%～18.8%。处理至抽雄期和灌浆期，胞间CO₂浓度分别增加152%和161%，均极显著高于对照(p<0.01)；蒸腾速率的变化较小。高浓度CO₂处理下，玉米穗粒数和穗粒重均明显高于对照(p<0.05)。CO₂浓度升高在一定程度上促进了玉米的光合作用，从而使玉米子粒产量增加。

Effects of Elevated CO2 Concentration on Photo-physiological Characteristics of Maize Leaves

In order to reveal effect mechanism of elevated carbon dioxide (CO₂) concentration on maize(Zea mays L.)photo-physiological characteristics and grains yield, open-top chambers(OTCs) were utilized to investigate the change of chlorophyll content, photo-physiological characteristics in maize leaves and grains yield on maize under elevated CO₂ concentration treatmen. The results indicated that compared with control, chlorophyll a, chlorophyll b and chlorophyll (a+b) contents increased respectively, while the ratio of chlorophyll a to b ascended first and declined then under elevated CO₂ concentration treatment in the whole growing period. Compared with the control, net photosynthetic rate increased by 12.6% - 71.1% (p>0.05) and stomatal conductance decreased by 2.9% - 18.8% (p>0.05) during the whole treatment period. In tasseling and filling stage, intercellular CO₂ concentration presented highly significant difference (p<0.01) compared with the control, raised respectively 152% and 161%, while transpiration rate changed a little. Under elevated CO₂ exposure, the spike grains number and grain weight per panicle increased significantly (p< 0.05). In conclusion, elevated CO₂ concentration accelerated the photosynthesis of maize in some extent, which enhanced the grains yield of maize.