Effect of Rare Earths on Plant under Supplementary Ultraviolet-B Radiation: Ⅰ Effect of Cerium on Growth and Photosynthesis in Rape Seedlings Exposed to Supplementary Ultraviolet-B Radiation  

作　　者：梁婵娟 黄晓华 周青 

机构地区：[1]Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi 214036, China [2]College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, China

出　　处：《Journal of Rare Earths》2005年第5期569-575,共7页稀土学报（英文版）

基　　金：ProjectsupportedbytheNationalNaturalScienceFoundationofChina(20471030)andtheFoundationofStatePlanningCommittee(GFZ040628)

摘　　要：Effect of cerium （Ce^3＋） on growth and photosynthesis in rape seedlings exposed to two levels of ultraviolet-B radiation （UV-B, 280 - 320 nm） was studied with hydroponics under laboratory conditions. The growth of rape seedlings exposed to two levels of UV-B irradiation （0.15 and 0.35 W· m^-2/T2） was both heavily restrained. The aboveground growth indices including stem （plant） height, leaf number, leaf area, leaf fresh/dry weight and stem fresh/dry weight were obviously decreased by 13.2% - 44.1% （T1） and 21 .4% - 49.3% （T2）. Compared to CK, and except active absorption area of roots, the belowground indices main root length, root volume and fresh/dry weight by 14.1% -35.6% （T1） and 20.3% - 42.6% （T2）, respectively. For Ce ＋ UV-B treatments, the aboveground and belowground growth indices were decreased by 4.1% - 23.6%, 5.2% -23.3% （Ce＋T1） and 10.8% -28.4%, 7.0% -27.8% （Ce ＋T2）, lower than those of UV-B treatments mentioned above. These results show that Ce has protective effect on plant against injury of UV-B radiation. Furthermore, the protective effect of Ce on seedlings exposed to T1 level of UV-B radiation is superior to T2 level. Chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency in UV-B treatments decrease dramatically, whereas intercellular CO2 concentration increases. Although these indices in Ce ＋ UV-B treatments decrease compared with those of CK, the decrease in Ce ＋ UV-B treatments are lower than those in UV-B treatment. This phenomenon indicates that the ecophysiological protective effect of Ce is based on improving photosynthesis in plants. The dynamic curves of photosynthesis indices show that the course of light-repair is shortened and the injury to rape seedlings by UV-B radiation stress is alleviated by Ce.Effect of cerium （Ce^3＋） on growth and photosynthesis in rape seedlings exposed to two levels of ultraviolet-B radiation （UV-B, 280 - 320 nm） was studied with hydroponics under laboratory conditions. The growth of rape seedlings exposed to two levels of UV-B irradiation （0.15 and 0.35 W· m^-2/T2） was both heavily restrained. The aboveground growth indices including stem （plant） height, leaf number, leaf area, leaf fresh/dry weight and stem fresh/dry weight were obviously decreased by 13.2% - 44.1% （T1） and 21 .4% - 49.3% （T2）. Compared to CK, and except active absorption area of roots, the belowground indices main root length, root volume and fresh/dry weight by 14.1% -35.6% （T1） and 20.3% - 42.6% （T2）, respectively. For Ce ＋ UV-B treatments, the aboveground and belowground growth indices were decreased by 4.1% - 23.6%, 5.2% -23.3% （Ce＋T1） and 10.8% -28.4%, 7.0% -27.8% （Ce ＋T2）, lower than those of UV-B treatments mentioned above. These results show that Ce has protective effect on plant against injury of UV-B radiation. Furthermore, the protective effect of Ce on seedlings exposed to T1 level of UV-B radiation is superior to T2 level. Chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency in UV-B treatments decrease dramatically, whereas intercellular CO2 concentration increases. Although these indices in Ce ＋ UV-B treatments decrease compared with those of CK, the decrease in Ce ＋ UV-B treatments are lower than those in UV-B treatment. This phenomenon indicates that the ecophysiological protective effect of Ce is based on improving photosynthesis in plants. The dynamic curves of photosynthesis indices show that the course of light-repair is shortened and the injury to rape seedlings by UV-B radiation stress is alleviated by Ce.

关 键 词：CERIUM ultraviolet-B radiation rape seedlings PHOTOSYNTHESIS rare earths 

分 类 号：S565.4[农业科学—作物学]