Brassinosteroids alleviate heat-induced inhibition of photosynthesis by increasing carboxylation efficiency and enhancing antioxidant systems in Lycopersicon esculentum
Brassinosteroids alleviate heat-induced inhibition of photosynthesis by increasing carboxylation efficiency and enhancing antioxidant systems in Lycopersicon esculentum
复制标题
油菜素类固醇通过提高番茄中的羧化效率和增强抗氧化系统来减轻热诱导的光合作用抑制
DOI：
10.1007/s00344-007-9030-7
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发表时间：
2008-03-01
影响因子：
4.8
通讯作者：
Nogues, Salvador
中科院分区：
文献类型：
--
作者：
Ogweno, Joshua Otieno;Song, Xing Shun;Nogues, Salvador
为了研究外源油菜素类固醇对植物耐热性的影响，测定了番茄叶片的CO2同化作用、叶绿素荧光参数和抗氧化酶代谢。CV。9021)施或不施24-表油菜素内酯(EBR)的植物。番茄植株在40/30℃下暴露8天，然后回到最佳条件下4天。高温显著降低了叶片的净光合速率(P(N))、气孔导度(G(S))、Rubisco的最大羧化速率(V-Cmax)、1，5-二磷酸核酮糖(RuBP)的最大电子传递速率以及PSII光化学相对量子效率(Phi(PSII))、光化学猝灭(Q(P))和非光化学猝灭(NPQ)。然而，在热胁迫过程中，只有轻微的可逆光抑制发生。有趣的是，EBR预处理显著缓解了高温对光合作用的抑制。超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、愈创木酚过氧化物酶(GPOD)和过氧化氢酶(CAT)等抗氧化物酶活性在热处理过程中均有不同程度的提高，其中以EBR处理的提高最为显著。在高温胁迫下，EBR处理也降低了总过氧化氢(H_2O_2)和丙二醛(MDA)含量，同时显著增加了地上部重量。结果表明，EBR可通过提高叶片的羧化效率和增强抗氧化酶系统来缓解高温对植物生长的不利影响。
To investigate the effects of exogenously applied brassinosteroids on the thermotolerance of plants, leaf CO2 assimilation, chlorophyll fluorescence parameters, and antioxidant enzyme metabolism were examined in tomato (Lycopersicon esculentum Mill. cv. 9021) plants with or without 24-epibrassinolide (EBR) application. Tomato plants were exposed to 40/30C for 8 days and then returned to optimal conditions for 4 days. High temperature significantly decreased the net photosynthetic rate (P (n)), stomatal conductance (G(s)), and maximum carboxylation rate of Rubisco (V-cmax), the maximum potential rate of electron transport contributed to ribulose-1,5-bisphosphate (RuBP), as well as the relative quantum efficiency of PSII photochemistry (phi(PSII)), photochemical quenching (q(P)), and increased nonphotochemical quenching (NPQ). However, only slight reversible photoinhibition occurred during heat stress. Interestingly, EBR pretreatment significantly alleviated high-temperature-induced inhibition of photosynthesis. The activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidase (GPOD), and catalase (CAT) increased during heat treatments, and these increases proved to be more significant in EBR-treated plants. EBR application also reduced total hydrogen peroxide (H2O2) and malonaldehyde (MDA) contents, while significantly increasing shoot weight following heat stress. It was concluded that EBR could alleviate the detrimental effects of high temperatures on plant growth by increasing carboxylation efficiency and enhancing antioxidant enzyme systems in leaves.