CO2浓度升高对玉米叶片光合生理特性的影响

Effects of Elevated CO_2 Concentration on Photo-physiological Characteristics of Maize Leaves

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。

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.