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不同光质下‘黄金芽’叶片颜色变化与感光基因表达

2019-07-05  作者: admin  来源: 未知  已阅读

光质是影响植物光形态建成的关键环境因子。‘黄金芽’作为光敏感型黄化茶树品种,在强光下叶片呈现亮黄色且富含氨基酸。在本研究中,作者探索了不同光质处理下‘黄金芽’叶片颜色以及光合色素积累的差异。实验处理为三年生的‘黄金芽’幼苗进行盆栽,分别用红光、蓝光、红光+蓝光(1:1)的LED灯进行照射处理,对照为白光,每个处理用苗8盆、每盆5株,共处理15天。结果发现红光处理下叶片颜色最绿,叶绿素A、B以及A+B含量最高,而白光下最低;另外,相比与白光,在红光和蓝光处理下,叶片的光合系统II光化学效率(PSII photochemical efficiency,ΦPSII)更低而非光化学猝灭(Nonphotochemical quenching,NPQ)值更高;此外,感光光敏色素基因CsPHYA、CsPHYB、CsPHYE 在红光处理下上调表达,蓝光处理下隐花色素基因CsCRY1和CsCRY2表达最高,而白光下它们的表达最低。同时作者还指出在相比其他光照处理,白光在510~610 nm波长范围内有一个明显的波峰,预示着在此波长下可能存在不同于PHY和CRY类的感光元件调控‘黄金芽’叶片保持黄色。

 

 

 


Abstract

Light quality is considered one of the most important environmental factors for plant photomorphogenesis. ‘Huangjinya’ is a novel light-sensitive albino tea cultivar with bright yellow leaves and a high amino acid content. To investigate the effects of light quality on the color change process in ‘Huangjinya’, the leaf color phenotypes, photosynthetic pigments, chlorophyll fluorescence parameters, and photoreceptor gene expression in ‘Huangjinya’ were evaluated when the tea plants were exposed to red, blue, red + blue (red: blue = 1:1), and white LED light for 15 days. Among the four different light treatments, the highest contents of chlorophyll a, b and a + b in the greenest ‘Huangjinya’ leaves were obtained under red light, while the lowest contents were obtained under white light. Light quality noticeably affected some chlorophyll fluorescence parameters of ‘Huangjinya’. Lower ΦPSII and higher NPQ values of the tea plant leaves were found under the red and blue light treatments than under the white light treatment. The photoreceptor phytochrome genes CsPHYACsPHYB, and CsPHYE were upregulated in ‘Huangjinya’ when exposed to red light. In addition, blue light induced high expression levels of the cryptochrome genes CsCRY1 and CsCRY2 in ‘Huangjinya’. The lowest expression levels of both CsPHY and CsCRYwere found under white light among the four different light qualities. In conclusion, the leaf color of ‘Huangjinya’ remained green under red light, which was partly due to high chlorophyll contents. Moreover, in ‘Huangjinya’, red light strongly induced high expression levels of the phytochrome genes CsPHYA and CsPHYB, which may be involved in chlorophyll synthesis and leaf color changes. Interestingly, the yellowest ‘Huangjinya’ leaves were obtained under white light, and the spectrum of white light was obviously different from that of the other lights at the wavelengths of 510˜610 nm. We hypothesized that there may be a photoreceptor in this range that senses and transmits light signals to induce the leaf color of ‘Huangjinya’ to remain yellow. In addition, we also found that red light increased the tea shoot length and slightly reduced the leaf area, while blue light induced tea shoot elongation and caused little leaf expansion.

 
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