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本文以一种C4植物——黍子(Panicum miliaceum)为材料,在白光、红光、蓝光、远红光和黑暗5种不同条件下培养黍子幼苗,叶片采收后用于叶绿素积累、叶绿体吸收光谱、叶绿体低温荧光发射光谱和高分子量cpRNA积累的测定以及psbA基因的Northern Blot分析。结果表明:白光、红光和蓝光下生长的黍子,它们的叶绿体都有功能完善的光合系统;而远红光下生长的黍子,已有光系统Ⅱ的发射峰,只是强度和波长都与白光、红光和蓝光下的有所不同;不同光质促进叶绿素积累和高分子量cpRNA积累的效率是平行的,其中红光较蓝光和远红光有效,而复合光(白光)的作用效果最好。当以白光诱导的积累量为100％时,可以分别求出不同光质诱导叶绿素积累和高分子量cpRNA积累的相对量,结果表明,高分子量cpRNA的积累对光的依赖性要比叶绿素积累对光的依赖性大得多。psbA基因的Northern Blot分析表明,不同光质下psbA转录物的积累与高分子量cpRNA的积累是一致的。据此我们推测,在黍子叶绿体的光诱导发育过程中,psbA的转录过程可能不受光信号的直接调控,而是受叶绿体整体发育状态的控制。
In this paper, millet seedlings were cultivated under five different conditions of white light, red light, blue light, far red light and darkness, using a kind of C4 plant, Panicum miliaceum. The leaves were harvested for chlorophyll accumulation, Absorption spectra, chloroplast hypothermia fluorescence emission spectra and accumulation of high molecular weight cpRNAs and Northern Blot analysis of the psbA gene. The results showed that millet grown under white light, red light and blue light had perfect photosynthetic system in their chloroplasts. The millet grown under far red light had the emission peak of photosystem Ⅱ, but both intensity and wavelength Which is different from white light, red light and blue light. The efficiency of different light qualities in promoting the accumulation of chlorophyll and accumulation of high molecular weight cpRNA is parallel, with red light being more effective than blue light and far red light, while the effect of composite light (white light) the best. When the amount of white light-induced accumulation is 100%, the relative amounts of different light-induced chlorophyll accumulation and high-molecular-weight cpRNA accumulation can be calculated separately. The results show that the accumulation of high-molecular-weight cpRNA is more light dependent than chlorophyll The dependence is much larger. Northern Blot analysis of the psbA gene showed that the accumulation of psbA transcripts was consistent with the accumulation of high molecular weight cpRNAs under different light qualities. Based on this, we speculate that during the light-induced development of millet chloroplast, transcription of psbA may not be directly regulated by light signals, but controlled by the overall development of chloroplasts.