磷和CO2浓度变化对苦草光合生理的影响

为了阐明CO₂浓度和水环境要素变化对沉水植物生长的影响, 采用室外模拟的方法, 研究了不同磷和CO₂浓度条件下苦草叶片(Vallisneria natans)光合生理特征。实验结果表明, 当水体磷浓度处于较高水平时, 苦草叶片荧光参数V_j、M_o降低, 参数ABS/CS_o、DI_o/CS_o、TR_o/CS_o、RC/CS、P_ET显著升高, 其他荧光参数则无显著变化; 高浓度的CO₂在显著降低苦草叶片V_j、ABS/RC、DI_o/RC、ABS/CS_o、DI_o/CS_o的同时, 也显著提高了苦草叶片ψ_o、φ_Eo、ET_o/RC、PI_ABS、F_v/F_m、P_TR、P_ET的参数值, 而对其他荧光参数无显著影响; 在磷与CO₂交互作用方面, 磷与CO₂在V_j、M_o、ψ_o、TR_o/CS_o、RC/CS和P_ET处存在显著的交互作用, 其他荧光参数不显著。可见, 磷或CO₂浓度变化均能显著影响苦草叶片光合生理状态, 高浓度的CO₂可有效改善苦草叶片PSⅡ反应中心光化学性能、电子传递能力及单位有活性反应中心能量的分配, 从而提高苦草叶片的光合能力; 高浓度的磷可在一定程度上改善苦草叶片PSⅡ受、供体状态及电子传递性能。此外, 磷和CO₂存在交互作用, 协同影响苦草叶片的光合能力。

EFFECTS OF PHOSPHORUS AND CO2 ON PHOTOSYNTHESIS PHYSIOLOGICAL OF VALLISNERIA NATANS

In order to evaluate the impact of changes in atmospheric and water environment on aquatic plants, we study the photosynthesis physiological of V. natans under different phosphorus and CO2. The results showed that the fluores-cence Vj、Mo of V. natans reduced when the concentration of phosphorus in the water was at a high level, but the ABS/CSo, DIo/CSo, TRo/CSo, RC/CS and PET increased at the same time; high concentration of CO2 significantly re-duced Vj, ABS/RC, DIo/RC, ABS/CSo and DIo/CSo of V. natans, but improved the level of ψo, φEo, ETo/RC, PIABS, Fv/Fm, PTR and PET. There was a significant impact of phosphorus and CO2 on Vj, Mo, ψo, TRo/CSo and RC/CS of V. natans. The change of phosphorus and CO2 concentration could significantly affect the photosynthetic physiological of V. natans; high concentration of CO2 can improve the performance of photosynthesis of V. natans leaves by promoting photochemical propertieselectron, transfer process and optimizing the distribution of energy among PSⅡ; while high concentration of phosphorus have significant promotion on the donor and acceptor of PSⅡ, and it also improved the electron transfer properties of V. natans. Moreover, there was an interaction of phosphorus and CO2 on photosynthetic physiological of V. natans.