UV-B辐射增强对芦苇光合生理及叶绿体超微结构的影响

在UV-B辐照增强条件下,研究不同辐照梯度对芦苇光合特性、光合色素含量及叶绿体超微结构的影响. 结果表明: 与自然光照相比,UV-B辐照增强显著降低芦苇叶片净光合速率、气孔导度、蒸腾速率,且随辐照强度增大,降低程度加剧,胞间CO₂浓度升高,光合效率显著降低;与自然光照相比,UV-B辐照增强显著降低芦苇叶片光合色素含量(包括叶绿素a、叶绿素b、总叶绿素和类胡萝卜素),且随辐照强度增大,降低程度加剧;UV-B辐射增强条件下,叶绿体超微结构遭到破坏,表现为叶绿体结构变形,类囊体片层排列稀疏紊乱、膨胀甚至模糊不清,并且UV-B辐射强度越大,损伤越大,高强度UV-B辐射对叶绿体超微结构的影响大于低强度辐射.

Effects of enhanced UV-B radiation on photosynthetic physiology and chloroplast ultrastructure of Phragmites australis

The effects of different intensities of UV-B radiation on photosynthetic characteristics, photosynthetic pigment content and chloroplast ultrastructure of Phragmites australis were studied in this paper. The results showed that enhanced UV-B radiation significantly reduced the net photosynthetic rate, stomatal conductance and transpiration rate, and the degree of degradation increased with the increasing irradiation intensity. The intercellular CO₂ content increased and the photosynthetic efficiency decreased significantly compared with the control. Enhanced UV-B radiation decreased photosynthetic pigment contents, including chlorophyll a, chlorophyll b, total chlorophyll and carotenoid, and the decrement increased with the increasing irradiation intensity. Under the enhanced UV-B radiation treatment, chloroplast structure was damaged, and thylakoid lamellae was disorde-red, swelling and even blurred. The effect of high intensity of radiation on chloroplast ultrastructure was greater than that of lower intensity of radiation.