UV-B辐射增强对甘薯光合特性和紫外吸收物质的影响

为探索UV-B辐射增强对甘薯光合特性和紫外吸收物质含量的影响,以徽薯为试验材料,以自然光为对照,设2个UV-B辐射增强处理在自然光基础上增加UV-B辐射3.6和7.2kJ/(m ²·d)分别编号为T1、T2处理],测定不同辐射强度下光合色素含量、光合作用参数和紫外吸收物质含量。结果表明：叶绿素a（Chla）、叶绿素b（Chlb）、类胡萝卜素（Car）和叶绿素a/b的值均随UV-B辐射强度的增加而降低,且Chla、Chlb和Car分别在处理第100、80和40天时对辐射变化最敏感;净光合速率（P_n）显著下降,气孔导度（G_s）降低,胞间CO₂浓度（C_i）和蒸腾速率（T_r）无明显变化规律,气孔限制值（L_s）的变化趋势与C_i相反;紫外吸收物质显著升高,呈CK

Effects of Enhanced UV-B on Photosynthetic Characteristics and UV-Absorbing Compounds of Sweet Potato

To explore the effects of UV-B enhancement on photosynthetic characteristics and UV-absorbing compounds contents of sweet potato. Using ‘Huishu’ as the test material and the natural light as a comparison, two treatments were added UV-B 3.6kJ/(m ²·d) (T1) and 7.2kJ/(m ²·d) (T2) on the basis of the natural light, respectively. The photosynthetic pigment contents, photosynthetic parameters and UV-absorbing compounds contents were examined under the different radiations. The results showed that: the contents of chlorophyll a (Chla), chlorophyll b (Chlb), carotenoid (Car) and chlorophyll a/b all decreased with the increase of the UV-B intensity. The Chla, Chlb and Car were the most sensitive to the intensity changes at 100th, 80th and 40th day, respectively. The net photosynthetic rate (P_n) decreased significantly, stomatal conductance (G_s) increased first and then decreased, intercellular carbon dioxide concentration (C_i) and transpiration rate (T_r) showed no obvious variation, while stomatal limitation (L_s) showed an opposite trend with C_i. The UV-absorbing compounds were significantly increased, showing a trend of CK