不同强度UV-B辐射胁迫对蚕豆幼苗生长及叶绿素荧光特性的影响

采用人工增强UV-B辐射的方法,研究了蚕豆幼苗生长及叶绿素荧光特性对不同强度UV-B辐射的响应.结果表明:不同强度UV-B辐射使幼苗植株矮化达50%以上,叶面积减小,干物质量减少23.3%～61.49%;可溶性糖及可溶性蛋白含量均显著降低;叶绿素含量下降,其中叶绿素a降低幅度比叶绿素b大;0.25W/m2的UV-B辐射使蚕豆幼苗叶片的Fv/Fm、Fv/F0、φPSⅡ、qP等荧光参数值显著下降.根据结果推测,增加不同强度UV-B辐射首先导致幼苗叶绿素含量减少,可溶性蛋白含量减少,进而降低PSⅡ反应中心活性,最终导致光合作用能力下降,减少了干物质的合成和积累.在本试验强度范围内,辐射强度为0.25W/m2时,其抑制作用最显著.幼苗植株的矮化及叶面积的减小是植物对增强UV-B辐射的一种适应方式.

The Effects of Different Treatments with UV-B Radiation Stress on Seedling Growth and Character of Chlorophyll Fluorescence of Vicia faba L.

Broad bean(Vicia faba L.)seedlings were grown under artifical enhanced UV-B radiation stress, which was used to research the responses of the growth and character of chlorophyll fluorescence of them. The results showed that enhanced UV-B radiation would shorten the seedling height by more 50%,and minish the leaf areas,and reduce the dry matter accumulation by 23.3%～61.49% ,meanwhile the soluble sugar and soluble protein contents decreased evidently . The contents of Chlorophyll reduced, and the change extend of chlorophyll a was larger than chlorophyll b. Under the UV-B radiation of 0.25 W/m~2 , the chorophyll fluorescence of Fv/Fm, Fv/F0, φPS Ⅱ , qP declined obviously. When UV-B was enhanced, the chlorophyll content of seedling were declined firstly, the contents of Rubisco decreased; then the reaction center of PSⅡ was decreased, finally which led to the photosynthesis weakened, and the synthetical and unused dry material decreased. The restrain effect under the intensity of 0.25 W/m~2 UV-B is obviously; the shortening of seedling and the minish of leaf area are manners to adapt to UV-B for plant.