Changes in morphological plasticity of Ulva prolifera under different environmental conditions: A laboratory experiment
Changes in morphological plasticity of Ulva prolifera under different environmental conditions: A laboratory experiment
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不同环境条件下石莼形态可塑性的变化：室内实验
DOI：
10.1016/j.hal.2016.09.004
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发表时间：
2016-11-01
期刊：
影响因子：
6.6
通讯作者：
Xu, Juntian
中科院分区：
文献类型：
--
作者：
Gao, Guang;Zhong, Zhihai;Xu, Juntian
自2008年以来，黄海西部沿海地区每年都会出现以藻藻为主的大规模绿潮，对当地环境和经济造成巨大影响。为了解释其在绿潮中的优势地位，人们对其生理特性进行了大量的研究。然而，关于多刺藤通过形态变异对环境因子变化的响应，文献报道甚少。在我们的实验中，我们发现了不同温度（20和25℃）和盐度（10、20和30）条件下的显著形态驯化。在较低的温度和盐度条件下培养时，其分支较多，但较短。为了探讨这些形态变异在其适应环境因子变化中的意义，测定了不同生长条件下的多刺藤的生理生化性状。较高的温度提高了相对生长速率，而盐度对相对生长速率没有影响。另一方面，较高的温度没有提高净光合速率，而较低的盐度有提高净光合速率。低盐度条件下净光合速率的增加可能是由于在低盐度条件下有更多的分枝，导致菌体中有更多的光合色素叶绿素a、叶绿素b和类胡萝卜素。增加枝数和增加菌体强度可能有助于保护菌体免受低盐度引起的渗透压增加的影响，但这导致了更多的遮荫。为了在遮荫时捕获足够的光，在较低的盐度水平下，藻体合成了更多的光合色素。此外，温度升高可提高硝酸盐还原酶活性和可溶性蛋白含量，但盐度变化对其没有影响。研究结果表明，在实验室环境下，多殖菌可以通过形态驱动的生理生化变化来适应环境因子（盐度和温度）的变化。我们认为，在不断变化的海洋环境中，藻藻的形态可塑性可能是其战胜其他藻类的重要因素。(C) 2016 Elsevier B.V.版权所有
The large-scale green tides, consisting mainly of Ulva prolifera, have invaded the coastal zones of western Yellow Sea each year since 2008, resulting in tremendous impacts on the local environment and economy. A large number of studies have been conducted to investigate the physiological traits of U. prolifera to explain its dominance in the green tides. However, little has been reported regarding the response of U. prolifera to changing environmental factors via morphological variation. In our experiments, we found remarkable morphological acclimation of U. prolifera to various temperature (20 and 25 degrees C) and salinity (10, 20, and 30) conditions. U. prolifera had more, but shorter branches when they were cultured at lower temperature and salinity conditions. To investigate the significance of these morphological variations in its acclimation to changes of environmental factors, physiological and biochemical traits of U. prolifera grown under different conditions were measured. Higher temperature increased the relative growth rate while salinity did not affect it. On the other hand, higher temperature did not enhance the net photosynthetic rate whilst lower salinity did. The increased net photosynthetic rate at lower salinity conditions could be attributed to more photosynthetic pigments chlorophyll a, chlorophyll b, and carotenoids in thalli due to there being more branches at lower salinity conditions. Increased numbers of branches and thus an increased intensity of thalli may be helpful to protect thalli from increased osmotic pressure caused by lower salinity, but it led to more shading. In order to capture enough light when being shaded, thalli of U. prolifera synthesized more photosynthetic pigments at lower salinity levels. In addition, higher temperature increased nitrate reductase activity and soluble protein content but variations in salinity did not impose any effect on them. Our results demonstrate conclusively that U. prolifera can acclimatize in the laboratory to the changes of environmental factors (salinity and temperature) by morphology-driven physiological and biochemical variation. We suggest that the morphological plasticity of U. prolifera may be an important factor for it to outcompete other algal species in a changing ocean. (C) 2016 Elsevier B.V. All rights reserved.