24-Epibrassinolide Ameliorates Endogenous Hormone Levels to Enhance Low-Temperature Stress Tolerance in Cucumber Seedlings.
24-Epibrassinolide Ameliorates Endogenous Hormone Levels to Enhance Low-Temperature Stress Tolerance in Cucumber Seedlings.
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DOI：
10.3390/ijms19092497
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发表时间：
2018-08-24
影响因子：
5.6
通讯作者：
Li Y
中科院分区：
文献类型：
--
作者：
Anwar A;Bai L;Miao L;Liu Y;Li S;Yu X;Li Y
植物激素的合成和积累对植物的生长发育和逆境反应至关重要。研究了低温胁迫下24-表油菜素内酯（EBR）对黄瓜叶片生理生化机制的影响。黄瓜幼苗处理如下：NT（常温，26°C/18°C日/夜）和3个低温（12°C/8°C日/夜）处理：CK（低温胁迫）；EBR（低温和0.1 μM EBR）；BZR（低温和4 μM BZR， EBR特异性生物合成抑制剂）。结果表明，低温胁迫显著降低了黄瓜幼苗生长和壮苗指数、叶绿素含量、光合能力和抗氧化酶活性，提高了活性氧（ROS）和丙二醛（MDA）含量、激素水平和EBR生物合成基因表达水平。而EBR处理显著提高了黄瓜幼苗生长和强苗指数、叶绿素含量、光合能力、抗氧化酶活性、细胞膜稳定性和内源激素，上调了EBR生物合成基因表达水平，降低了ROS和MDA含量。综上所述，外源EBR在转录水平上通过激活EBR生物合成基因调控内源激素，提高抗氧化酶能力水平，减少ROS和MDA的过量产生，保护叶绿素和光合机制，从而促进黄瓜幼苗生长。
Phytohormone biosynthesis and accumulation are essential for plant growth and development and stress responses. Here, we investigated the effects of 24-epibrassinolide (EBR) on physiological and biochemical mechanisms in cucumber leaves under low-temperature stress. The cucumber seedlings were exposed to treatments as follows: NT (normal temperature, 26 °C/18 °C day/night), and three low-temperature (12 °C/8 °C day/night) treatments: CK (low-temperature stress); EBR (low-temperature and 0.1 μM EBR); and BZR (low-temperature and 4 μM BZR, a specific EBR biosynthesis inhibitor). The results indicated that low-temperature stress proportionately decreased cucumber seedling growth and the strong seedling index, chlorophyll (Chl) content, photosynthetic capacity, and antioxidant enzyme activities, while increasing reactive oxygen species (ROS) and malondialdehyde (MDA) contents, hormone levels, and EBR biosynthesis gene expression level. However, EBR treatments significantly enhanced cucumber seedling growth and the strong seedling index, chlorophyll content, photosynthetic capacity, activities of antioxidant enzymes, the cell membrane stability, and endogenous hormones, and upregulated EBR biosynthesis gene expression level, while decreasing ROS and the MDA content. Based on these results, it can be concluded that exogenous EBR regulates endogenous hormones by activating at the transcript level EBR biosynthetic genes, which increases antioxidant enzyme capacity levels and reduces the overproduction of ROS and MDA, protecting chlorophyll and photosynthetic machinery, thus improving cucumber seedling growth.
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影响因子：
5.3
作者：
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通讯作者：
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