Keywords C pool;CO_2 exchange;distribution;elevated CO_2;Leymus chinensis steppe;open top chamber;photosynthetic rate;plant biomass;respiration rate;species composition;

• 生物量;种类组成;碳贮量;CO_2交换;CO_2浓度升高;羊草草原;开顶式气室;光合速率;呼吸速率;