Effect of Elevated CO_2 Concentration on Leaf Photosynthesis in Sanjiang-Deyeux/a Angustifolia

摘要

Deyeuxia angustifolia were grown under three different levels of CO_2 concentration conditions, 370umol mol~(-1)(ambient CO_2), 550μmol mol~(-1)(elevated CO_2) and 700μmol mol~(-1) (elevated CO_2) respectively. We investigated the responses of photosynthesis and growth of D. angustifolia under different CO_2 concentration conditions. Leaf photosynthesis and chlorophyll content were checked. The results showed that the values of net photosynthetic rate (Pn), stomatal conductance(Gs), intercellular CO_2 concentration(Ci), transpiration(E), chlorophyll content were influenced by the elevated CO_2 concentrations. The photosynthetic parameters changed in parallel with CO_2 enrichment. CO_2 enrichment in short term improved the photosynthetic ability of leaves, whereas the capacity was weakened under long-term elevated CO_2 concentration condition. The leaves of D. angustifolia grown under elevated CO_2 concentrations at the end of growth, had lower Pn, Gs, Ci, E and chlorophyll content than those grown and measuered under ambient CO_2 concentration. The results indicated that D. angustifolia appeared photosynthetic acclimation.