无芒雀麦和燕麦种子萌发过程中叶绿体光合变化

Chloroplast Photosynthesis during Seed Germination of Smooth Bromegrass and Oat

本研究以无芒雀麦(Bromus inermis Leyss.)和燕麦(Avena sativa L.)种子为试验材料,利用锡纸包裹培养皿模拟黑暗5~6天,揭开锡纸模拟种子萌发,分析胚芽光谱表型、光合色素含量及叶绿素光合荧光参数。结果表明,无芒雀麦和燕麦照光后胚芽表型发生显著变化,无芒雀麦与燕麦胚芽光合色素含量整体呈上升趋势:叶绿素a和叶绿素b揭开锡纸第1天光照第1 h(E1 h)后缓慢积累,光照1天(E1 d)后迅速增加;类胡萝卜素在E1 d先下降后迅速升高。叶绿素荧光参数整体上升,无芒雀麦PSII最大光学效率(F_(v)/F_(m))在E1h—E1d迅速上升,PSII有效光化学量子产量(F_(v)′/F_(m)′)在E2.5h—E1d上升,燕麦F_(v)/F_(m)和F_(v)′/F_(m)′在E1h—E1d上升。综上,无芒雀麦和燕麦种子在揭开锡纸后的E1h—E1d为叶绿体发生重要阶段,在E1 d后叶绿体结构基本发育成熟。本试验结果为深入研究禾本科牧草种子萌发叶绿体生物发生提供支持,对解析叶绿体生物发生动态变化规律具有重要意义。

In this study,smooth bromegrass and oat seeds were used as experimental materials.The culture dishes wrapped in tinfoil were used to simulate the darkness for 5~6 days,and then the tinfoil was unwrapped to simulate the germination.The spectral phenotype,photosynthetic pigment content and chlorophyll photosynthetic fluorescence parameters of the plumule of two species were analyzed during this period.The results showed that,the phenotypes of the plumule of smooth bromegrass and oat were significantly changed after being exposed to light,and the contents of photosynthetic pigments showed an overall increasing trend:Chlorophyll a and chlorophyll b accumulated slowly for 1 h(E1h)of light exposure in the first day,and increased rapidly after 1 d(E1d)of light exposure.Carotenoid content decreased in E1d and then increased rapidly.The chlorophyll fluorescence parameters showed an overall trend of increase,among which,in smooth bromegrass the maximum optical efficiency(F_(v)/F_(m))and effective photochemical quantum yield(F_(v)′/F_(m)′)of PSII increased in E1h-E1d and E2.5h-E1d,respectively;and tended to be stable after E1d.In contrast,F_(v)/F_(m)and F_(v)′/F_(m)′of oat increased gradually during E1h-E1d.In conclusion,the important stage of chloroplast formation is from 1 hour to 1 day(E1h-E1d)after the smooth bromegrass and oat seeds were exposed to light from the embedded darkness,and the chloroplast function was basically developed and matured after E1d.The results in this study will provide support for further study for the chloroplast biogenesis during seed germination of gramineous forages,and have certain significance for the analysis of the dynamic changes during seed germination.