紫花苜蓿对CO_2倍增的反应:生态生理研究和模型拟合  

RESPONSES TO DOUBLED CO_2 IN MEDICAGO SATIVA: STUDIES ON ECOPHYSIOLOGY AND SIMULATION MODELLING

作　　者：项斌[1] 林舜华[1] 高雷明[1] 

机构地区：[1]中国科学院植物研究所,北京100093

出　　处：《Acta Botanica Sinica》1996年第1期63-71,共9页Acta Botanica Sinica（植物学报：英文版）

基　　金：国家自然科学重大基金

摘　　要：研究了紫花苜蓿（Ｍｅｄｉｃａｇｏ ｓａｔｉｖａ）在ＣＯ２ 倍增下光合作用、蒸腾作用、气孔导度、水分利用效率的生态生理变化，并在此基础上对苜蓿进行了生态生理模型化的研究。在倍增（７００ μｍ ｏｌ·ｍ ｏｌ－ １）和对照（３５０ μｍ ｏｌ·ｍ ｏｌ－ １） ＣＯ２ 浓度下，对紫花苜蓿的生态生理学的研究表明，光合作用有效辐射是影响瞬时表观光合速率的主要环境因子，而气孔导度主要受相对湿度的限制。以整个生育期计，倍增组的表观光合作用比对照组可提高１８．７％ ，气孔导度略有下降（２％ ），蒸腾作用减少了２．７％ ，水分利用效率提高了３０．１％ 。还对生理指标的实测数据进行了模型化的研究。对光合作用模型和气孔导度模型中参数的拟合结果表明，ＣＯ２ 倍增条件下，紫花苜蓿的光能转化效率（α）、电子传递速率（Ｊｍ ａｘ）比对照组都有明显的提高。A world wide spread forage grass, Medicago sativa, was grown in two open top chambers maintained at either normal (350 μmol·mol -1 )or doubled (700 μmol·mol -1 ) CO 2 concentration, from seedling to maturity. During the whole growth season, ecophysiological measurements and observations were conducted over different phenological stages and the main results were as follows: (1) With similar environmental factors, in terms of RH(relative humidity), irradiance, and watering, a slight shift in temperature (about 0.77 ℃,averaged over the whole growth season) within the chamber maintained at doubled CO 2 did not affect instantaneous physiological processes at leaf level, but had some impacts on the effect of doubled CO 2 over a long period. (2) Over the whole growth season, physiological variables showed differences between two chambers. The net photosynthesis of plant grown under higher CO 2 increased by 18.7%, while stomatal conductance fell slightly as compared with that of the control. So was the water use efficiency which was also 30.1% higher than the control. Based on the above results from field studies, we concluded that photosynthetically active radiation (PAR) and RH were the main factors affecting photosynthesis and stomatal behavior. Then we combined a widely accepted model of C 3 leaf photosynthesis with an empirical model of stomatal conductance and made some modifications according to our experiments. This model was parameterized using field data sets of net CO 2 assimilation, stomatal conductance, intercellular CO 2 concentration of plants grown at both doubled and control CO 2 levels. Variances of main parameters between two treatments reflected some biochemical changes in leaf cell. The maximum efficiency of light energy conversion(α) increased by 22% and light saturated rate of electron transport(J max ) rose by 15%. The maximum stomatal conductance was slightly reduced by 8%. The increases in parameters (α and J max ) indicate accelerated biochemical proc

关 键 词：紫花苜蓿 CO2浓度 生态生理作用 生态生理模型 

分 类 号：S551.701[农业科学—作物学]