《植物生理学报》 2018, 54(10): 1615-1623
通信作者：翟衡；E-mail: zhaih@sdau.edu.cn, sunyongjiang12@163.com
摘 要：
以‘赤霞珠’葡萄一年生植株为试材, 通过测定植株各器官的内源褪黑素(MT)、MT合成前体物质5-羟色胺(5-HT)和MT的主要代谢产物2-羟基褪黑素(2-OHMel)含量、叶片快速叶绿素荧光动力学曲线, 结合叶绿素荧光淬灭分析, 探讨了外源MT对干旱胁迫下葡萄内源MT及其关键代谢物的响应以及叶片光抑制的缓解作用。结果表明: 干旱胁迫后, 植株不同器官的内源MT、5-HT及2-OHMel含量有明显的时空变化, 诱导了嫰梢和成叶中MT的积累。与干旱胁迫相比, 干旱+喷施MT和干旱+浇灌MT处理均显著提高了植株地上部MT的含量及部分器官中5-HT和2-OHMel的含量。干旱胁迫后, 快速叶绿素荧光曲线(OJIP)形状发生明显改变, 最大荧光(Fm)、叶片最大光化学效率(Fv/Fm)、光系统线性电子传递速率ETR(I)和ETR(II)均显著下降, 非光化学淬灭(NPQ)显著升高, 喷施和浇灌MT处理均使叶片Fm值升高, 增强了叶片对光能的利用效率, 线性电子传递速率明显提高。综上, 干旱胁迫导致‘赤霞珠’葡萄叶片光系统活性发生较严重的抑制, 但促进了植株中褪黑素的合成。外源MT缓解了光系统活性的抑制程度, 促进MT在植株各器官中的代谢和分配, 缓解干旱胁迫对葡萄叶片光合作用的伤害程度。关键词：干旱胁迫; 葡萄; 叶绿素荧光; 褪黑素; 5-羟色胺; 2-羟基褪黑素
收稿：2018-05-30 修定：2018-10-18
资助：国家自然科学基金(31572084)、现代农业产业技术体系(CARS-29-zp-02)、长江学者创新团队(IRT15R42)和山东省“双一流”建设奖补资金(SYL2017YSTD10)。
Corresponding author: ZHAI Heng; E-mail: zhaih@sdau.edu.cn, sunyongjiang12@163.com
Abstract:
The potted ‘Cabernet Sauvignon’ grapevines were used to investigate the effect of exogenous melatonin on endogenous MT, the synthetic precursor of MT (5-hydroxytryptamine, 5-HT), the main metabolite of MT (2-hydroxymelatonin, 2-OHMel) and the alleviating effects on photoinhibition under drought stress. The contents of endogenous MT, 5-HT and 2-OHMel, OJIP fluorescence transient, and chlorophyll fluorescence quenching were determined. The results showed that there were obvious temporal and spatial changes in the contents of endogenous MT, 5-HT and 2-OHMel in different organs of plants under drought stress, which induced the accumulation of MT in shoots and leaves. Compared with drought stress, drought+spraying MT and drought+irrigating MT significantly increased the MT contents in the aboveground organs, and the 5-HT and 2-OHMel contents in some other organs. Under drought stress, the shape of OJIP curve was obviously changed, Fm, leaf maximum photochemical efficiency (Fv/Fm), the linear electron transport rate of PSI [ETR(I)] and PSII [ETR(II)] were significantly decreased, and the non-photochemical quenching (NPQ) increased significantly. Both spraying and irrigating MT increased the Fm value in leaves, enhanced the leaf light use efficiency, and increased the linear electron transfer rate significantly. In summary, drought stress induced the inhibition of photosystem activity in grapevine leaves, but promoted the synthesis of MT in the plant. The exogenous MT treatment alleviated photoinhibition, promoted the metabolism and distribution of MT in various organs of plants, alleviated the damaged degree of photosynthesis of grapevine leaves by drought stress.Key words: drought stress; grapevine; chlorophyll fluorescence; melatonin; 5-hydroxytryptamine; 2-hydroxymelatonin
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