Brassinosteroids alleviate high-temperature injury in Ficus concinna seedlings via maintaining higher antioxidant defence and glyoxalase systems
Brassinosteroids alleviate high-temperature injury in Ficus concinna seedlings via maintaining higher antioxidant defence and glyoxalase systems
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DOI：
10.1093/aobpla/plv009
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发表时间：
2015-01-01
期刊：
影响因子：
2.9
通讯作者：
Zhu, Xiang Tao
中科院分区：
文献类型：
--
作者：
Jin, Song Heng;Li, Xue Qin;Zhu, Xiang Tao
虽然油菜素甾醇（BR）在植物发育和胁迫耐受性中起着至关重要的作用，但它们发挥这些作用的机制却知之甚少。本文研究了外源BR对高温胁迫48 h的美丽榕幼苗活性氧（ROS）、抗氧化防御和丙酮醛（MG）解毒系统的影响。结果表明，两种高温胁迫下，抗坏血酸过氧化物酶（APX）、超氧化物歧化酶（SOD）、谷胱甘肽S-转移酶（GST）、谷胱甘肽过氧化物酶（GPX）和谷胱甘肽转移酶II（Gly II）的活性均升高。过氧化氢酶（CAT）和脱氢抗坏血酸还原酶（达尔）的活性与对照相比没有变化。谷胱甘肽还原酶（GR）、单脱氢抗坏血酸还原酶（MDHAR）和谷胱甘肽酶I（Gly I）的活性仅在中度高温胁迫下才升高。尽管有这些保护机制，HT应激诱导F。结果表明，随着处理时间的延长，幼苗叶片中活性氧、丙二醛（MDA）和MG含量增加，叶绿素含量和相对含水量下降。中度高温胁迫对还原型谷胱甘肽（GSH）和抗坏血酸（阿萨）含量无明显影响。单独喷施24-表油菜素（EBR）对非酶抗氧化剂和抗氧化酶活性影响不大。高温胁迫下EBR预处理可提高GSH和阿萨含量，维持GSH和阿萨的高氧化还原状态，进一步提高SOD、GST、GPX、APX、MDHAR、GR、达尔、Gly I和Gly II的活性，降低ROS、MDA和MG的含量，增强ROS和MG的解毒作用。因此，EBR可能通过增强F.椰子幼苗
Although brassinosteroids (BRs) play crucial roles in plant development and stress tolerance, the mechanisms by which they have these effects are poorly understood. Here, we investigated the possible mechanism of exogenously applied BRs on reactive oxygen species (ROS), antioxidant defence and methylglyoxal (MG) detoxification systems in Ficus concinna seedlings grown under high-temperature (HT) stress for 48 h. Our results showed that the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPX) and glyoxalase II (Gly II) were increased under two levels of HT stress. Compared with control the activities of catalase (CAT) and dehydroascorbate reductase (DHAR) were not changed due to HT stress. The activities of glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and glyoxalase I (Gly I) were increased only at moderate HT stress. Despite these protective mechanisms, HT stress induced oxidative stress in F. concinna seedlings, as indicated by the increased levels of ROS, malondialdehyde (MDA) and MG, and the reductions in chlorophyll levels and relative water content. The contents of reduced glutathione (GSH) and ascorbate (AsA) were not changed under moderate HT stress. Spraying with 24-epibrassinolide (EBR) alone had little influence on the non-enzymatic antioxidants and the activities of antioxidant enzymes. However, EBR pretreatment under HT stress resulted in an increase in GSH and AsA content, maintenance of high redox state of GSH and AsA, and enhanced ROS and MG detoxification by further elevating the activities of SOD, GST, GPX, APX, MDHAR, GR, DHAR, Gly I and Gly II, as evident by lower level of ROS, MDA and MG. It may be concluded that EBR could alleviate the HT-induced oxidative stress by increasing the enzymatic and nonenzymatic antioxidant defence, and glyoxalase systems in F. concinna seedlings.