Photosynthesis of Ulva lactuca at Different tidal Levels During Submergence and Emergence
Photosynthesis of Ulva lactuca at Different tidal Levels During Submergence and Emergence
复制标题
不同潮位沉水和出水期间石莼的光合作用
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
Y. Rao
中科院分区：
文献类型：
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作者：
M. S. Murthy;J. Naresh;P. Faldu;Y. Rao
石莼叶片的相对光合速率。（石莼，绿藻）采样从上，中，下沿岸的带，在实验室条件下，淹没时，在不同程度的干燥进行了测量。上部和中部的沿岸的叶暴露于空气中的光合速率增加，但较低的沿岸的的表现出最大的速率下淹没和注册下曝光率较低。在干燥条件下，上部沿岸的叶的比率显著高于下部叶。在淹水过程中，上部叶片的含水量高于中部和下部沿岸的叶片，但在脱水过程中，上部叶片的失水速度较快。光合速率开始下降的水分水平分别为上、中、下沿岸的叶的45%、72%和100%。从这项研究中推断，该物种的上部沿岸的叶，这是受到较长的曝光时间，因此更多的干燥在出现在自然界中，更好地适应出现的条件比低的。结果进一步表明，这三种类型的叶状体可能是当地适应ecads或生态型，其差异的结果，他们的物理条件的操作沿着潮间带。关键词：石莼，潮间带，海藻，脱水，光合作用，ecad，生态型，沉水，出苗
The relative photosynthetic rates of fronds of Ulva lactuca Linn. (Ulvales, Chlorophyceae) sampled from upper, middle and lower littoral zones, were measured when submerged and at different levels of desiccation under laboratory conditions. The upper and middle littoral fronds showed increased rates of photosynthesis under exposure to air but the lower littoral ones showed maximal rates under submergence and registered lower rates under exposure. The rates of the upper littoral fronds were significantly higher than those of lower ones, under desiccated conditions. The upper ones had higher moisture content than the middle and lower littoral fronds during submergence but they were fast to lose their moisture under desiccation. The moisture levels at which the photosynthetic rates began to fall were 45%, 72% and 100%, in the upper, middle and lower littoral fronds, respectively. It is inferred from this study that the upper littoral fronds of the species, which are subjected to longer periods of exposure and consequently more desiccation during emergence in nature, are better adapted to emerged conditions than the lower ones. The results further suggest that the three types of fronds could be locally adapted ecads or ecotypes, the differences being the outcome of their responses to the physical conditions operating along the intertidal belt. Key-words: Ulva lactuca, intertidal, seaweeds, desiccation, photosynthesis, ecad, ecotype, submergence, emergence