UV-B辐射下不同树龄杜仲叶片光合及部分生理特性的变化

采用试验园栽培,研究模拟不同强度UV-B辐射对不同树龄(1、3、5年生)杜仲苗叶片的光合特性和部分生理指标的影响,以期揭示UV-B辐射对杜仲苗胁迫效应的规律。结果表明:随着紫外辐射(1.40~2.81 kJ·m^-2·d^-1)强度的增强,净光合速率、气孔导度、蒸腾速率均呈下降趋势,1、3年生杜仲叶片中叶绿素质量分数均下降,5年生杜仲的叶绿素质量分数升高;抗氧化酶中抗坏血酸过氧化物酶、过氧化氢酶、过氧化物酶活性降低(P<0.05),而1、3年生杜仲叶片中超氧化物歧化酶活性升高;丙二醛浓度及黄酮、总酚、单宁的质量分数均显著增加(P<0.05)。综合光合和生理隶属函数均值分析表明,5年生杜仲的抗UV-B辐射的能力强。

Changes of Photosynthetic and Physiological Characteristics in Eucommia ulmoides Oliver Leaves of Different Tree Ages under UV-B Radiation

In order to reveal change of UV-B radiation on different tree ages Eucommia ulmoides Oliver(EUO)seedlings,the effects of simulated UV-B radiation on physiological and photosynthetic characteristics of EUO leaves were studied by the cultivation with experimental garden.The results showed that with the increase of UV-B radiation intensity(1.40-2.81 kJ·m^-2·d^-1),net photosynthetic rate,stomatal conductivity,and transpiration rate showed a downward trend in EUO at different tree ages.The chlorophyll content showed a decreasing trend in leaves of EUO at one and three tree age,and chlorophyll content showed an upward trend in five tree ages.The activities of APX,CAT and POD in antioxidant enzymes were decreased(P<0.05),and the activity of SOD in leaves of EUO was increased in one and three tree ages.The content of malondialdehyde(MDA),flavonoids,total phenol and tannin were significantly increased(P<0.05).The mean value of photosynthetic and physiological membership function showed that five-tree-age EUO had strong ability to resist UV-B radiation.