大米草对CO2浓度的光合和蒸腾响应

Responses of Photosynthesis and Transpiration Characteristics of Spartina anglica to Different CO2 Concentration

关键词:  光合作用  蒸腾  CO₂浓度  大米草

Key words:  photosynthesis  transpiration  CO₂ concentration  Spartina anglica

摘要:

以大米草(Spartina anglica Hubbard)为材料,研究在不同CO₂浓度下其净光合速率(P_n)、蒸腾速率(T_r)、胞间CO₂浓度(C_i)、气孔导度(G_s)、叶面饱和蒸气压亏缺(V_pdl)以及水分利用效率(WUE)的变化。结果表明,CO₂浓度从50μmol·mol^-1增至1000μmol·mol^-1的过程中,大米草P_n、C_i、V_pdl和WUE逐渐增大,G_s和T_r逐渐下降。低于环境CO₂浓度范围内时,大米草对CO₂浓度的升高比较敏感,反之则不明显。WUE和T_r对CO₂浓度升高的响应极显著(P<0.01)。CO₂浓度升高能够明显降低单位面积叶片的蒸腾失水,提高光合速率和水分利用效率,增强大米草的竞争优势。

Abstract:

The net photosynthesis (P_n), transpiration (T_r), intercellular CO₂ concentration (C_i), stomatal conductance (G_s), vapor pressure deficit at the leaf surface (V_pdl) and WUE of Spartina anglica under different CO₂ concentration were measured with Licor-6400 Portable Photosynthesis System.The results indicated that P_n、C_i、V_pdl and WUE increased with CO₂ concentration between 50 and 1 000 μmol·mol^-1.But G_s and T_r dropped as the CO₂ concentration increased.It was concluded than P_n of Spartina anglica was sensitive to CO₂ concentration variation which was below than that actual content, it was not sensitive on the contrary.The response of T_r and WUE was most significant to CO₂ concentration (P<0.01).The increasing of CO₂ concentration could significantly decrease the transpiration, increase the photosynthetic rate, the utilization rate of water as well as the competitive advantage of Spartina anglica.