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以紫花苜蓿(金皇后)为试验材料,UV-B辐射增强5%(T_1)和增强10%(T_2),研究了当年生紫花苜蓿光合荧光特性和地上生物量在重度刈割下对增强UV-B辐射的响应。结果表明:在刈割前后两个生育期中,与CK相比,随着UV-B强度增加各指标均呈下降趋势;在T_1处理下,与刈割前相比,刈割后紫花苜蓿Chla、Chlb、Chl(a+b)、净光合速率和荧光参数F_v/F_m在分枝期和结荚期均显著增加;在T_2处理下,在分枝期和结荚期,刈割也显著增强了紫花苜蓿Chla、Chlb、Chl(a+b)、净光合速率和F_v/F_m,增幅分别高达32%、30%、20%、17%和22%;地上生物量随着生育期的推进而增加,与刈割前相比,刈割后T_1和T_2处理的增幅分别高达49%和199%;方差分析表明,刈割与增强UV-B处理对紫花苜蓿光合特性和荧光参数的交互作用不明显;表明适度刈割在一定程度上可以缓解UV-B辐射对紫花苜蓿造成的伤害。
With alfalfa (golden queen) as test material, UV-B radiation was enhanced by 5% (T_1) and enhanced by 10% (T_2). The photosynthetic fluorescence characteristics and aboveground biomass of alfalfa B radiation response. The results showed that compared with CK, the indexes decreased with the increase of UV-B intensity in both growth stages before and after cutting. Under the treatment of T 1, compared with that before CK, the indexes of Chla, Chlb and Chl (a + b), net photosynthetic rate and fluorescence parameter F_v / F_m both increased significantly during the branching and podding stages. Under the T_2 treatment, the mowing also significantly increased at the branching and podding stages Alfalfa Chla, Chlb, Chl (a + b), net photosynthetic rate and F_v / F_m increased up to 32%, 30%, 20%, 17% and 22% respectively. Aboveground biomass increased with the growth period , Compared with that before cutting, the increase of T_1 and T_2 treatments were 49% and 199% respectively. Analysis of variance showed that the interaction between mowing and enhanced UV-B treatment had no obvious interaction on photosynthetic characteristics and fluorescence parameters of alfalfa The results showed that moderate cutting could alleviate the damage caused by UV-B radiation to alfalfa to a certain extent.