作 者 ：夏钦,何丙辉*,刘玉民*,徐健
期 刊 ：生态学报 2010年 30卷 19期 页码：5217~5224
Keywords:Scaevola albida, high temperature stress, morphological change, physiological response,
摘 要 ：对粉带扦插苗进行高温处理，研究高温胁迫对其外观形态和生理生化指标的影响。结果表明，35 ℃高温胁迫或40 ℃高温胁迫短时间(2d)内，扦插苗受害指数和大部分生理生化指标均与对照差异不显著，粉带未产生热伤害；40 ℃高温胁迫长时间(3d)或45 ℃高温胁迫短时间(2d)内，粉带产生较严重的热伤害，但植株仍能自我调节和恢复，受害指数、可溶性蛋白、可溶性糖、Pro、MDA含量、SOD和CAT活性均急剧上升，叶绿素、类胡萝卜素含量明显减少，POD活性略有降低；45 ℃高温胁迫3d，对粉带产生热伤害，各项生理生化指标急剧下降，40%的扦插苗整株萎蔫枯死，大部分植株已无法通过自身调节恢复。粉带叶片的叶绿素、Pro、MDA含量和POD活性在高温胁迫时变化明显，且4种指标与受害指数之间具有显著相关性，其相关系数绝对值均在0.88(P<0.001)以上，可作为耐热性鉴定指标。
Abstract:High temperature stress is one of the important ecological factors affecting growth and development, and physiological characteristics in many plants. On the other hand, plants adapt different strategies for improving high temperature tolerance during their life cycling. Scaevola albida is a popular ornamental flowering crop cultivated as a bedding plant or as a beautiful cultivar in hanging baskets. Pink Ribbon, one of Scaevola albida′s cultivated species originated from Australia, is a perennial herb with characteristics of fan-shaped flowers, a long flowering period, and easily cutting propagation. It has been reported that continuous high temperature would generate adverse influence on S. albida′s growth, but the damage mechanisms of high temperature stress have not fully understood. Because S. albida is introduced to China for the first time, less is known its ability of adapting to the new environment and habitat in China. The effects of high temperature on the appearance shape, physiological and biochemical indices in S. albida cutting seedlings were investigated in Chongqing, China. The purpose of the project was to reveal the physiological adaptation mechanisms of S. albida to high temperature in order to provide a theoretical basis for the introduction and cultivation of this species in some regions with high temperature in summer, such as Chongqing. In the study, four temperatures: 35 ℃/27 ℃ (10 hour day/14 hour night), 40 ℃/30 ℃, 45 ℃/32 ℃, 25 ℃/22 ℃(control) were set up as the levels of treatment, and 30 S. albida cutting seedlings were randomly selected as subjects in each of the four temperature treatments. The cutting seedlings were experienced the temperature treatment for 3 days as a processing cycle, and the observations and measurements started at the end of 1, 2 and 3 days after treatment, respectively. The results showed that compared to the control, the injury indices and most of physiological indices of the cutting seedlings were no significant differences under the high temperature stress of 35/27 ℃ for 3 days or 40/30 ℃ for 2 days, and S. albida did not show symptoms of heat injury. Under the treatment of 40/30 ℃ for 3 days or 45/32 ℃ for 2 days, some serious heat injuries were produced, but the seedlings were still able to recover from the damages. The injury indices, the contents of soluble protein, soluble sugar, Pro and MDA, the activities of SOD and CAT were significantly higher in the treatments than in the control, while the contents of Chlorophyll and Carotenoid were obviously lower, and the activity of POD decreased slightly. Under the treatments of 45/32 ℃ for 3 days, the severe heat injuries were produced and most of the cutting seedlings could not be able to recover from the considerable damages. Each of the physiological and biochemical indices decreased dramatically, and 40% of the examined cutting seedlings were wilted to death. As the heat tolerance of plants is a genetic expression result from comprehensive physiological and biochemical processes, it is difficult to judge the synthetic adaptability of plants to heat press using a single thermal indicator. Our studies demonstrated that the contents of Chlorophyll, Pro, MDA and the activity of POD were changed obviously to the high temperature stress, and the four variables had remarkable correlations with the injury indices (the absolute values of the correlation coefficients > 0.88 for each variable) and, therefore, they could be used as heat tolerance indices of S. albida.
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