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| 干露胁迫对鼠尾藻生理生化影响的研究 |
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袁艳敏1, 刘福利1,2, 梁洲瑞1, 张朋艳1, 刘义1,3, 郑言鑫4, 张海宁5
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1.中国水产科学研究院黄海水产研究所 农业农村部海洋渔业可持续发展重点实验室 山东 青岛 266071;2.中国海洋大学海洋生命学院 海洋生物遗传学与育种教育部重点实验室 山东 青岛 266003;3.上海海洋大学水产与生命学院 上海 201306;4.中国水产科学研究院长岛增殖实验站
山东 烟台 265800;5.国家海洋局北海信息中心 山东 青岛 266061
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| 摘要: |
| 鼠尾藻(Sargassum thunbergii)集生于中潮带和低潮带岩石上，在高、中潮带的水陆或石沼中，有的甚至在低潮时较长时间暴露于日光下。低潮露空下的干露胁迫是影响鼠尾藻生存的关键因子。本研究采集野生鼠尾藻为实验材料，在培养箱中分别失水干露0、1、3、6 h，并在海水中恢复培养，测定不同胁迫时间下藻体的失水率、叶绿素荧光参数和生化参数。结果显示，不同大小的鼠尾藻干露胁迫不同时间后的失水率显著不同，胁迫时间越短，藻体越大，失水率越低，大藻体鼠尾藻的保水能力高于小藻体；干露胁迫使鼠尾藻的叶绿素荧光值显著降低，同株鼠尾藻不同部位对干露胁迫的耐受程度显著不同，梢部耐受能力较差，基部耐受能力较强，小藻体和大藻体的梢部伤害较大，不能恢复，鼠尾藻基部可恢复正常生理状态，干露胁迫时，鼠尾藻以非调节性能量耗散机制为主；干露胁迫时，藻体梢部通过抗氧化酶类[(抗超氧阴离子自由基(ASAFR)、超氧化物歧化酶(SOD))和非抗氧化物质(可溶性糖、脯氨酸)共同作用来应对胁迫，藻体基部主要是通过上调蛋白、可溶性糖和脯氨酸等含量抵抗胁迫。高中潮带的鼠尾藻较易处于高温、强光和干露失水叠加的胁迫状态，同时，又因外部形态和生活环境的不同，藻体各部分的生理生化特性也有一定的差异。本研究探讨了鼠尾藻干露胁迫下的生理生化状态，对研究鼠尾藻抵抗环境胁迫的生态适应性具有重要的指导意义。 |
| 关键词: 鼠尾藻 干露胁迫 失水率 叶绿素荧光参数 生化特性 |
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| Study on the physiological and biochemical influence of Sargassum thunbergii under dehydration |
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YUAN Yanmin1, LIU Fuli1,2, LIANG Zhourui1, ZHANG Pengyan1, LIU Yi1,3, ZHENG Yanxin4, ZHANG Haining5
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1.Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Qingdao, Shandong 266071, China;2.Ministry of Education, Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong 266003, China;3.College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China;4.Changdao Enhancement and Experiment Station, Chinese Academy of Fishery Sciences, Yantai, Shandong 265800, China;5.North China Sea Data and Information Service of SOA, Qingdao, Shandong 266061, China
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| Abstract: |
| Sargassum thunbergii is distributed on reefs and rock marshes in mid- and low-tide zones, and some are periodically exposed to lengthy low tides. Dehydration is a key factor affecting the survival of S. thunbergii at low tides. In this study, using wild S. thunbergii as experimental material, the water loss rate, chlorophyll fluorescence parameters, and biochemical parameters under different stresses were determined by dehydrating the thalli in an incubator for 0, 1, 3, and 6 h. The results showed that: (1) algae of different sizes have significantly different water loss rates under different stresses. The shorter the stress time and the larger the algae, the lower the water loss rate, indicating that the water retention capacity of S. thunbergii with larger thalli is higher. Wild S. thunbergii grow in clusters on reefs. The leaves in the lower part of the branches and near the holdfast are wide. The middle and upper leaves are narrow and long, respectively. The lower broad leaves are easily blocked by the upper branches. Therefore, differences in the growth environment cause differences in the ecological structure and biochemical components of S. thunbergii. High temperature, strong light, and water loss at low tide are the main factors that cause severe environmental stress to sessile S. thunbergii in the intertidal zone. (2) Dehydration significantly reduced the chlorophyll fluorescence value of S. thunbergii, and different parts of the same individual of S. thunbergii had significantly different tolerance to dehydration, with the lowest tolerance at branch tips and the strongest tolerance at the base. The non-regulatory energy-dissipation mechanism plays a major role in the dehydration response of S. thunbergii. Under dry exposure, the light energy utilization efficiency of S. thunbergii was significantly reduced. This reduction in active light protection capacity indicates that dehydration reduces the adaptability of S. thunbergii to excessive light intensity. Dehydration can damage the tips of small individuals that cannot recover, while the base part of large individuals could return to a normal physiological state. (3) Antioxidant enzymes (ASAFR, SOD) and non-antioxidant substances (soluble sugar and proline) in the tip part responded to dehydration, and the base part mainly responded by upregulation of protein, soluble sugar, and proline content to resist stress. S. thunbergii, located in the high and middle tide zones, is more likely to be stressed by high temperatures, strong light, and dehydration, and the physiological and biochemical characteristics of different parts of the thallus are also variable due to differences in external morphology. Algae mainly reduce damage to the photosynthetic system caused by a lack of water through a non-regulatory energy dissipation mechanism. The water retention capacity of the base was better than branch tips during dry exposure, and the damage to algal cells was low. The main roles are as heat shock proteins, soluble sugars, proline, and other small molecules, which can pass stress response, osmotic regulation, and anti-oxidation resists damage to cells caused by stress. The water retention capacity of the top cells was weak, and the stress was relatively strong. Antioxidant enzymes such as ASAFR and SOD in algae and non-antioxidant enzymes such as soluble sugars and proline, work together to resist dry exposure stress, reduce cell damage and maintain cell viability. In summary, under the stress of dry exposure, the antioxidant enzymes, antioxidant substances, and non-regulatory energy dissipation mechanisms of S. thunbergii play a role in maintaining cell activity. This study provides important guidance for exploring the ecological adaptability of S. thunbergii in resisting environmental stress. |
| Key words: Sargassum thunbergii Dry exposure Rate of water loss Chlorophyll fluorescence parameters Biochemical property |
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