增强UV-B辐射对光氧化水稻812HS光合特性和生长的影响

为了解光氧化水稻的光合特性对UV-B辐射的反应,以籼稻两用不育系812S(野生型)及其光氧化突变株系812HS为材料,在自然条件下,采用40 kJ·m^-2·d^-1剂量的UV-B增强辐射处理植株65 d,分别在幼苗期、分蘖期、拔节期、抽穗期、灌浆期进行相关生理指标检测和分析。结果表明,与自然光照条件相比,增强UV-B辐射使812HS的分蘖数和有效分蘖数减少,植株矮化,但对其生长抑制程度弱于普通水稻;812HS的叶绿素含量在分蘖期显著降低,但降低幅度低于普通水稻,抽穗期后叶绿素含量显著增加,尤其是在灌浆期,812HS叶绿体含量的增加幅度较普通水稻极显著多出34.3个百分点。增强UV-B辐射处理后,812HS的PSⅡ原初光转化效率(F_v/F_m)在分蘖期的提高幅度比普通水稻大,而在拔节期和灌浆期则明显低于普通水稻。PSⅡ失活的原因是质体醌PQs和PSI蛋白复合体对UV-B辐射敏感,电子从Q_A^-向QB^-传递过程受阻,致使快还原型库PQ受影响,说...

Effect of Enhanced UV-B Radiation on Photosynthetic Characteristics and Growth of Photooxidation Rice 812HS

To learn the effect of UV-B radiation on the photosynthesis of photooxidation rice, agronomic traits of an indica rice 812S (wild type, as an ordinary rice) and its leaf photooxidation mutant 812HS were studied. Under a natural condition, rice plants were treated with enhanced UV-B radiation at a dose of 40 kJ·m^-2·d^-1 for 65 days. The relevant physiological indexes were detected and analyzed at the stages of seedling, tillering, jointing, heading and filling. Compared with that under the natural light condition, enhanced UV-B radiation reduced the number of tillers and effective tillers of 812HS, and the plants were dwarfed, but the degree of inhibition was weaker than that of ordinary rice; the chlorophyll content of 812HS was significantly reduced at the tillering stage, which was lower than that of ordinary rice. However, after the heading stage especially in the filling stage, the chlorophyll content of 812HS increased significantly the increased percentage was 34.3 more than that of the wild type. After irradiated with the enhanced UV-B radiation, the initial light conversion efficiency (F_v/F_m) of PSII in 812HS was increased more than that in ordinary rice at the tillering stage, and decreased more than that in ordinary rice at the jointing and filling stages. The reason for PSII inactivation was that PQs and PSI protein complexes were sensitive to UV-B radiation, electrons were blocked from QA- to QB-, and the fast-recovery library PQ was affected. Enhanced UV-B radiation inhibited the photosynthesis and growth of rice, but the effects on photooxidation rice 812HS was lower than that on ordinary rice. The study is positive for increasing the understanding of rice photooxidation and physiology.