鱼池中叶绿素a和相关水质因子调查及藻蓝蛋白和微囊藻毒素合成酶基因的分析

发布时间：2018-03-28 09:45

本文选题：叶绿素a　切入点：蓝藻　出处：《上海海洋大学》2016年硕士论文

【摘要】：在养鱼池等封闭水体中,当蓝藻大量繁殖,会使水面形成一层蓝绿色的“水膜”,即水华。其中微囊藻、鱼腥藻等种类大量繁殖时,将会造成养鱼池大量减产。白天,微囊藻群体进行强烈的光合作用,遮蔽阳光,对水体中其它的植物光合作用产生了强烈的影响,晚上,藻体进行呼吸作用又会消耗水体中的氧气并产生大量的二氧化碳,严重影响池塘中浮游动、植物的生长繁殖,及鱼类生长。微囊藻外形呈颗粒状,由许多球形或长圆形的细胞组合而成,鱼类捕食后几乎无法进行消化。同时,由于微囊藻的蛋白质含量较高,在藻体死亡后,蛋白质分解产生硫化氢等物质,会对鱼类产生直接伤害,长期留存会造成鱼类中毒死亡。不仅如此,微囊藻体裂解后,其藻体内的微囊藻毒素(一种强烈的肝毒素)会释放到水体中,不仅危害鱼类健康,更会导致人类因饮用了污染水源或是食用了污染水体中的水生生物而健康受损,甚至死亡。泰国清迈地区淡水养殖业有着悠久的历史,由于常年的养殖,很多养殖废物在养殖环境中不断累积,造成了养殖水域的水污染很严重,致使水体富营养化的问题突出,并使淡水养殖的病害现象频繁发生。本文通过对清迈及其周边地区冬季和夏季的养鱼池中叶绿素a及相关水质因子调查,并通过分子生物学方法,运用实时荧光定量PCR技术对水体中藻类的藻蓝蛋白(phycocyanin,PC)操纵子基因和微囊藻毒素合成酶(mcyB)基因进行了检测。对不同的养鱼池与其他一些影响因子之间做了相关性分析,初步探讨了水体中各物理和化学因子对鱼池中藻类叶绿素a的影响,研究结果发现:在气温较高的夏季(5月)中,鱼池中叶绿素a浓度平均值为297.46μg/L,最高为1043.33μg/L,最低为13.58μg/L;而冬季(12月)叶绿素a浓度平均为186.01μg/L,最高为541.08μg/L,最低为1.67μg/L。夏季叶绿素a浓度比冬季明显高,约为冬季的1.5~3倍,最高达30倍。在冬季,各池塘中的不同深度的水层中的叶绿素a浓度趋近于一致,而夏季,各水层叶绿素a浓度则呈现出随着水深的增加而降低的趋势。除温度、营养盐含量外,酸碱度、浊度以及电导率,也会在一定的程度上,影响鱼池水体中的叶绿素a浓度。叶绿素a含量与池塘水体pH和浊度成正相关、而与电导率成负相关关系。根据鱼池水体的氮磷比推测,磷元素是该地区藻类生长的主要限制因素。冬季,大多数的养鱼池能产生微囊藻毒素的藻类(含有mcyB基因)占了水体中所用蓝藻类(由PC基因定量)数量的大部分(80%以上),但少数池塘水体中的mcyB基因的拷贝数要高于PC基因的拷贝数。夏季,多数鱼池水体中的总蓝藻数量较冬季没有显著增长,但少数鱼池由于水中总磷含量的升高,蓝藻大量繁殖。而且部分鱼池,其水体PC基因拷贝数显著高于mcyB基因,甚至无法检测出mcyB基因,显示夏季鱼池中有其他不含mcyB基因但含有PC基因的蓝藻类繁殖,甚至占据优势。
[Abstract]:In closed water bodies such as fish ponds, when cyanobacteria proliferate in large numbers, they will form a blue-green "water film" on the water surface, that is, Shui Hua. When microcystis, Anabaena and other species multiply in large numbers, the fish ponds will yield a lot less. During the day, The microcystis had a strong photosynthesis, obscured the sunlight, had a strong effect on other plants photosynthesis in the water, and at night, the algae breathing would consume oxygen and produce a large amount of carbon dioxide in the water. Seriously affecting phytoplankton, plant growth, and fish growth in ponds. Microcystis are granular in shape and are composed of many spherical or oblong cells, which are almost indigestible after predation. Because the protein content of microcystis is high, after the algae body dies, the decomposition of the protein produces hydrogen sulfide and other substances, which will directly harm the fish and lead to the death of fish poisoning for a long time. Not only that, but also after the microcystis are broken down, The microcystins (a strong hepatic toxin) released into the water not only harm fish health, but also damage human health by drinking polluted water sources or eating aquatic organisms in polluted water bodies. Even death. The freshwater aquaculture industry in Chiang Mai region of Thailand has a long history. As a result of the perennial cultivation, many aquaculture wastes are continuously accumulated in the aquaculture environment, resulting in serious water pollution in the aquaculture waters. The problem of eutrophication of water body is prominent and diseases of fresh water culture occur frequently. The chlorophyll a and related water quality factors in fish ponds in and around Chiang Mai in winter and summer were investigated in this paper. And through molecular biology, The phycocyanin operon gene and microcystin-synthase gene of algae in water were detected by real-time fluorescence quantitative PCR. The correlation between different fish culture ponds and other influencing factors was analyzed. The effects of various physical and chemical factors on the chlorophyll a of algae in fish ponds were preliminarily studied. The results showed that in summer (May) when the temperature was relatively high, The average value of chlorophyll a concentration in fish pond is 297.46 渭 g / L, the highest is 1043.33 渭 g / L, and the lowest is 13.58 渭 g / L, while in winter (December) the average chlorophyll a concentration is 186.01 渭 g / L, the highest is 541.08 渭 g / L, and the lowest is 1.67 渭 g / L. The highest is 30 times. In winter, the concentration of chlorophyll a in the water layers of different depths in each pond approaches to the same, while in summer, the concentration of chlorophyll a in each layer decreases with the increase of water depth. Except for the temperature, In addition to nutrient content, pH, turbidity and conductivity also affect the concentration of chlorophyll a in fish pond to a certain extent, and the content of chlorophyll a is positively correlated with pH and turbidity of pond water. According to the ratio of nitrogen and phosphorus in fish pond, phosphorus is the main limiting factor of algae growth in this area. Most algae (containing mcyB gene) that produce microcystins in fish ponds account for more than 80% of the amount of cyanobacteria (quantified by PC gene) used in the water, but the copy number of mcyB gene in a few ponds is more than 80%. Higher than the number of copies of the PC gene. The amount of total cyanobacteria in most fish ponds was not significantly increased compared with that in winter, but in a few fish ponds, due to the increase of total phosphorus content in water, cyanobacteria proliferated in large numbers. In some fish ponds, the copy number of PC gene in some fish ponds was significantly higher than that of mcyB gene. McyB gene could not even be detected, indicating that other cyanobacteria with no mcyB gene but PC gene were found in summer fish ponds.
【学位授予单位】：上海海洋大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S964.3;X52

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