短期UVB辐照对抱茎风毛菊光合作用的影响

以抱茎风毛菊(Saussurea chingiana)为实验材料,利用短期中波紫外线(UVB,Ultraviolet B)辐照对比实验(CK:对照组,自然大气UVB强度;UVB:UVB辐照度为205μw·cm~(-2),短期辐照时间为4h)研究了光合色素含量、叶绿素荧光快速诱导动力学曲线(OJIP)和光合蛋白表达量的变化。结果显示:UVB辐照降低了抱茎风毛菊的叶绿素质量分数,增大了叶绿素a/b比值和类胡萝卜素质量分数;UVB辐照导致PSII反应中心蛋白(D1、D2)、捕光色素蛋白(CP43)、Cytb6f复合物和ATP酶复合体蛋白均发生降解,外周捕光色素蛋白(LHCII)的表达量升高;UVB辐照抑制了从QA-往下的电子传递,增加了热耗散能量,阻碍了光合作用的碳同化过程,进而降低光能利用率。叶绿素a/b比值、类胡萝卜素含量的增大虽然缓解了短期UVB辐照对抱茎风毛菊的伤害,但是UVB辐照对光合作用仍具有显著的负影响。

The Influence of Short-term UVB Irradiation on Saussurea Chingiana Photosynthesis

Takes Saussurea chingiana as the experimental material,and the it uses short-term wave Ultra-violet B(UVB)irradiation as the comparative experiments (CK:control group,natural atmosphere UVB intensity;UVB:UVB irradiance of 205 μw?cm-2 ,short-term irradiation time of 4 h),which has studied the changes of photosynthetic pigment content,chlorophyll fluorescence rapid induction kinetics curves (OJIP)and photosynthetic protein expression.The results showes that:UVB irradiation reduces the chlo-rophyll mass fraction of Saussurea chingiana ,and increases the chlorophyll a/b ratio and carotenoid mass fraction;UVB irradiation has led the degradation of PSII reaction center protein(D1,D2),light-harvesting chlorophyll protein(CP43),Cytb6f compound and ATP enzyme compound protein,and the increase of ex-pression quantity of the light harvesting pigment-protein (LHCII).UVB irradiation inhibits the downward electron transfer of QA- ,increasing the heat dissipation energy,hindering the carbon assimilation process of photosynthesis,thus reducing the efficiency for solar energy utilization.Although the increase of chloro-phyll a/b ratio and carotenoid content has eased the damage of UVB irradiation tp the Saussurea chingi-ana ,UVB irradiation still has a significant negative impact on photosynthesis.