Photosynthetic Gas Exchange and Water Relation Responses of Three Tallgrass Prairie Species to Elevated Carbon Dioxide and Moderate Drought
Photosynthetic Gas Exchange and Water Relation Responses of Three Tallgrass Prairie Species to Elevated Carbon Dioxide and Moderate Drought
复制标题
三种高草草原物种对二氧化碳升高和中度干旱的光合气体交换和水关系响应
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
C. Owensby
中科院分区：
文献类型：
--
作者：
E. Hamerlynck;C. McAllister;A. Knapp;J. Ham;C. Owensby
未受干扰的tallgrass草原暴露于环境和升高（两倍环境）水平的大气CO2和实验干燥期。季节性和昼夜午间叶水势（单叶），净光合作用Anet，气孔导度（GS）的响应三个高草草原生长形式-C4草，Andropogon gerardii;阔叶木本C3灌木，Symphiocarpos orbiculatus;和C3多年生杂类草，鼠尾草-进行了评估。在A. gerardii和S. CO2浓度升高时，无论土壤湿度如何，圆叶海棠的生长量都较高，而三叶海棠的生长量较高。皮切里只对干旱作出反应。CO_2浓度升高对C_3物种的Anet有促进作用，而A. gerardii Anet仅在干燥条件下增加。然而，在C3种下，在CO2浓度升高的Anet下降与干旱，但不是在C4草。在潮湿的条件下，GS降低CO2升高的所有物种。在干燥期间，GS在CO2浓度升高有时高于环境CO2。我们的研究结果支持这样的说法，即CO2浓度升高将刺激高草草原生产力在干旱期间，并可能减少在这些草原生产力的时空变异。
Undisturbed tallgrass prairie was exposed to ambient and elevated (twice-ambient) levels of atmospheric CO2 and experimental dry periods. Seasonal and diurnal midday leaf water potential (Ψleaf), net photosynthesis Anet, and stomatal conductance (gs) responses of three tallgrass prairie growth forms—a C4 grass, Andropogon gerardii; a broad-leaved woody C3 shrub, Symphiocarpos orbiculatus; and a C3 perennial forb, Salvia pitcheri—were assessed. Ψleaf in A. gerardii and S. orbiculatus was higher under elevated CO2, regardless of soil moisture, while Ψleaf in S. pitcheri responded only to drought. Elevated CO2 always stimulated Anet in the C3 species, while A. gerardii Anet increased only under dry conditions. However, Anet under elevated CO2 in the C3 species declined with drought but not in the C4 grass. Under wet conditions, gs reduced in elevated CO2 for all species. During dry periods, gs at elevated CO2 was sometimes higher than in ambient CO2. Our results support claims that elevated CO2 will stimulate tallgrass prairie productivity during dry periods and possibly reduce temporal and spatial variability in productivity in these grasslands.