CaCl_2对UV-B辐射下菠菜叶片光合特性的影响

以"丹麦旺盛菠菜"为材料,通过UV-B和CaCl2复合处理,测定光合色素含量、Hill反应活力、叶绿素荧光、MDA含量和抗氧化酶活性等参数,探讨了CaCl2对UV-B辐射下菠菜叶片电子传递链和光合膜酶保护系统的影响。结果表明,UV-B处理下,光合色素含量、chl/car、类囊体膜上PSII潜在活性(Fv/Fo)、光化学淬灭系数(qP)、非光化学淬灭系数(qN)、PSII光量子产量(ΦPSⅡ)、原初光能转化效率(Fv/Fm),以及Hill反应活力等降低,chla/chlb和MDA含量升高;喷洒CaCl2可不同程度缓解UV-B的伤害。不同处理下,POD、SOD和CAT活性的变化呈现补偿效应。UV-B强度与菠菜叶片PSII功能受损程度呈正相关,CaCl2则主要通过提高chlb含量、类囊体膜上的光量子产量和POD活性,以缓解伤害。重度UV-B辐射下,CaCl2使chlb含量显著提高可能是导致PSII捕光效率提高的重要因素。

Effect of CaCl2 on photosynthetic characteristic of Spinacia oleracea under enhanced UV-B radiation

In order to reveal the effect of CaCl2 on photosynthetic characteristic of Spinacia oleracea under the enhanced UV-B radiation,the photosynthetic pigments,chlorophyll fluorescence,Hill reaction activity and MDA content were determined. The results showed that the treatments could decrease the content of chlorophyll a,chlorophyll b,total chlorophyll,potential activity of PSII(Fv/Fo),photochemical quenching(qP)and non-photochemical quenching(qN),light quantum yield of PSII(ΦPSⅡ),efficiency of primary conversion of light energy(Fv/Fm)on thylakoid membrane,and the activity of Hill reaction,whereas,the treatments could increase chl/car,and the content of MDA. The damage of spinach leaves caused by UV-B was relieved by CaCl2.With different treatments the change of the activity of SOD,POD,CAT was compensatory effect.The relationship between the UV-B intensity and the damaged degree of PSII function of spinach leaves was positive correlation. It appeared that the most primary action by CaCl2 radiation occured at the chlb content in total photosyntheic pigments,the light quantum yield and the activity of POD.Under the high UV-B stress,CaCl2 caused the chlorophyll b increase,which was the most important reason that efficiency of PSII capture light could raise.