The Regulation of Exogenous Jasmonic Acid on UV-B Stress Tolerance in Wheat
The Regulation of Exogenous Jasmonic Acid on UV-B Stress Tolerance in Wheat
复制标题
外源茉莉酸对小麦UV-B胁迫耐受性的调控
DOI：
10.1007/s00344-011-9253-5
复制
发表时间：
2012-09-01
影响因子：
4.8
通讯作者：
Jia, Enping
中科院分区：
文献类型：
--
作者：
Liu, Xiao;Chi, Hong;Jia, Enping
增强的紫外线-B辐射（UV-B，280-320 nm）被认为是不可忽视的环境胁迫因素之一。茉莉酸（JA）是植物防御生物和非生物胁迫的重要信号分子。为探讨外源茉莉酸（JA）在小麦抗UV-B辐射胁迫中的作用，用1和2.5mM茉莉酸预处理小麦幼苗，然后用0.9kJ m（-2）h（-1）UV-B辐射处理12 h，测定小麦幼苗抗氧化酶活性、丙二醛（MDA）含量、UV-B吸收物质含量、光合色素、测定了脯氨酸和叶绿素荧光参数。方差分析结果表明，UV-B、JA、UV-B对光系统II最大光化学效率（F（v）/F（m））无显著影响。邓肯的多量程试验表明，UV-B胁迫导致植物光系统II（PSII）功能和SOD活性显著降低，膜脂过氧化水平增加，表明UV-B辐射对小麦的有害影响。JA预处理通过提高F（v）/F（m）、反应中心激发能捕获效率（F（v）'/F（m）'）、有效光系统II量子产率（I破竖条PSII）和光合电子传递速率（ETR），以及降低小麦幼苗的非光化学猝灭（NPQ），明显减轻了UV-B对PSII功能的不利影响。此外，茉莉酸还能提高SOD活性、脯氨酸和花青素含量。但无论是否有UV-B的补充，外源JA均能提高叶片MDA含量，降低Car含量，而对叶绿素、类黄酮及相关酚类化合物含量无明显影响。同时，外源JA处理降低了UV-B辐射胁迫下CAT和POD活性。这些结果部分证实了外源JA在一定程度上可以抵消UV-B胁迫对小麦幼苗的负面影响。
Enhanced ultraviolet-B radiation (UV-B, 280-320 nm) is recognized as one of the environmental stress factors that cannot be neglected. Jasmonic acid (JA) is an important signaling molecule in a plant's defense against biotic and abiotic stresses. To determine the role of exogenous JA in the resistance of wheat to stress from UV-B radiation, wheat seedlings were exposed to 0.9 kJ m(-2) h(-1) UV-B radiation for 12 h after pretreatment with 1 and 2.5 mM JA, and the activity of antioxidant enzymes, the level of malondialdehyde (MDA), the content of UV-B absorbing compounds, photosynthetic pigments, and proline and chlorophyll fluorescence parameters were measured. The results of two-way ANOVA illustrated that the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), MDA level, anthocyanin and carotenoid (Car) content, and almost all chlorophyll fluorescence parameters were significantly affected by UV-B, JA, and UV-B x JA (P < 0.05) [the maximal efficiency of photosystem II photochemistry (F (v)/F (m)) was not affected significantly by UV-B radiation]. Duncan's multiple-range tests demonstrated that UV-B stress induced a significant reduction in plant photosystem II (PSII) function and SOD activity and an increased level of membrane lipid peroxidation, indicative of the deleterious effect of UV-B radiation on wheat. JA pretreatment obviously mitigated the detrimental effect of UV-B on PSII function by increasing F (v)/F (m), reaction centers' excitation energy capture efficiency (F (v)'/F (m)'), effective photosystem II quantum yield (I broken vertical bar PSII), and photosynthetic electron transport rate (ETR), and by decreasing nonphotochemical quenching (NPQ) of wheat seedlings. Moreover, the activity of SOD and the content of proline and anthocyanin were provoked by exogenous JA. However, the MDA level was increased and Car content was decreased by exogenous JA with or without the presence of supplementary UV-B, whereas the contents of chlorophyll and flavonoids and related phenolics were not affected by exogenous JA. Meanwhile, exogenous JA resulted in a decrease of CAT and POD activities under UV-B radiation stress. These results partly confirm the hypothesis that exogenous JA could counteract the negative effects of UV-B stress on wheat seedlings to some extent.