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为了探讨毛竹(Phyllostachys pubescens)茎秆的光合特性,以1龄和3龄毛竹为材料,观察了茎秆和叶中叶绿体的超微结构,测定了光合色素含量以及发射荧光光谱。结果表明:茎秆中叶绿体发育完整,其类囊体垛叠程度高于叶,并含有淀粉粒。茎秆中叶绿素总含量、类胡萝卜素及Chl a/b含量显著低于叶(P<0.05)。茎秆发射荧光光谱在735 nm处没有明显的主峰,1龄和3龄毛竹茎秆光系统II与光系统I的半峰宽比值分别比叶降低了7.0%和11.3%(P<0.05),峰高比值比叶分别增加了6.5%和18.3%(P<0.05)。四阶导数光谱在650–800 nm波长范围内出现了6个极大值,代表LHCII、CP43、CP47、RCI和LHCI的发射荧光峰以及PSI和PSII的发射荧光副振峰;其中,茎秆中RCI和LHCI特征发射荧光峰与叶相比有不同程度的红移。表明毛竹茎秆叶绿体通过提高Chl b的相对含量和增加类囊体垛叠以及降低LHCI含量,来适应毛竹茎秆以红光为主的光环境,进而协调激发能在2个光系统间的分配。
In order to investigate the photosynthetic characteristics of Phyllostachys pubescens, the ultrastructure of chloroplasts in stems and leaves of Phyllostachys pubescens was investigated. The content of photosynthetic pigments and the emission fluorescence spectra of Phyllostachys pubescens were determined. The results showed that the chloroplast in the stalks was well developed, the thylakoid accumulation was higher than that of the leaves, and contained starch granules. The content of total chlorophyll, carotenoid and Chl a / b in stems were significantly lower than those in leaves (P <0.05). The fluorescence spectra of stems showed no obvious peak at 735 nm, and the FWHM of photosystem I and photosystem I of the first and third instars were decreased by 7.0% and 11.3% (P <0.05), respectively. The ratio of height to height increased by 6.5% and 18.3% respectively than that of leaves (P <0.05). The fourth derivative spectra showed six maxima in the range of 650-800 nm, representing the emission fluorescence peaks of LHCII, CP43, CP47, RCI and LHCI and the emission fluorescence sub-peaks of PSI and PSII. Among them, The fluorescence emission peak of RCI and LHCI features different redshift compared with the leaf. The results showed that the chloroplast of Phyllostachys pubescens stem could adapt to the red light-dominated environment of the stem of bamboo by increasing the relative content of Chl b, increasing the stack of thylakoid and reducing the content of LHCI, and then coordinating the distribution of excitation energy between the two light systems .