增强UV-B辐射对真藓结皮生理特性的影响

Effects of enhanced UV-B radiation on physiological characteristics of Bryum argenteum

以中国腾格里荒漠地区广泛存在的生物土壤结皮——真藓为研究对象,在室内条件下研究了不同UV-B辐射强度对真藓光合作用、细胞膜完整性、可溶性蛋白、抗氧化酶等方面的影响。结果表明:经UV-B辐射处理的真藓叶绿素含量、叶绿素荧光参数、可溶性蛋白质含量及其抗氧化酶活性明显降低,且与辐射强度成正比,而丙二醛和类胡萝卜素含量随着辐射强度增加而增大。研究表明,UV-B辐射强度升高降低了真藓的光合速率,并造成了细胞膜的损伤,导致抗氧化酶系统的紊乱,而类胡萝卜素含量的升高,可能是其抵御UV-B胁迫的自我保护机制之一。

Taking the biological soil crust （Bryum argenteum） broadly existed in the Tengger Desert of China as test object, this paper studied the effects of UV-B radiation on the photosynthesis, cell membrane integrality, water-soluble protein content, and antioxidant enzymes activities of B. argenteum under laboratory condition. UV-B radiation decreased the chlorophyll content, chlorophyll fluorescence parameters, water-soluble protein content, and antioxidant enzymes activities of B. argenteum significantly, with the decrements positively proportional to the radiation intensity, while increased the malondiadehyde and carotenoid contents, with the increments increased with increasing radiation intensity. These results indicated that enhanced UV-B radiation intensity caused a significant reduction in the photosynthetic rate, cell membrane damage, and disorder of antioxidant enzyme system, but the increase of the carotenoid content with increasing radiation intensity could be one of the self-protection mechanisms of B. argenteum in resisting UV-B stress.