Comparison of Gas Exchange Traits of 30 Plant Species in Subalpine Meadow in Foping National Reserve of Qinling Mountains

The Qinling Mountain is one of the hotspots for biodiversity conservation in China,and the subalpine meadow vegetation can be an indicator of the environment change.We measured net photosynthetic rates,transpiration rates,stomatal conductance,water use efficiencies and intercellular carbon dioxide concentration of 30 species in subalpine meadow of the Qinling Mountain of Shaanxi province to explore the adaptation strategy of meadow to subalpine habitat.The results showed that the gas exchange traits were quite different between differert species.Ligularia hookeri had largest net photosynthesis rates(18.75 μmol·m^-2·s^-1),and Pedicularis verticillata had lowest photosynthesis rates(0.73 μmol·m^-2·s^-1).Anemone obtusiloba had largest stomatal conductance(2.99 mol·m^-2·s^-1),while Euphorbia hylonoma was the lowest(0.04 mol·m^-2·s^-1).Transpiration rates was largest in Fragaria orientalis(6.14 mmol·m^-2·s^-1)and lowest in Iris ruthenica(0.44 mmol·m^-2·s^-1).Pearson correlation analysis indicated that there were significantly positive correlations between net photosynthetic rates and stomatal conductance and transpiration rates(p<0.01).Based on the gas exchange traits data,these 30 species were divided into 4 groups by cluster analysis,and the diversity of gas exchange traits among species indicated the relative importance of different species in the subalpine meadow ecosystem.