摘要
采样分析了长江中下游浅水湖泊(鲁湖、梁子湖、后官湖、牛山湖、三角湖、龙阳湖、墨水湖、月湖以及太湖)沉积物多酚氧化酶与过氧化物酶活性的分布及其与微生物的关系。结果表明,在水平方向上,沉积物有机质含量较高的湖泊酶的活性明显较高,湖内酶的活性亦有明显的异质性,排污口、水生植物凋落区以及未疏浚点的活性明显较高。在垂直方向上,有机质含量较高的表层显示较高的多酚氧化酶活性。因此,不同来源的有机质均能诱导酶的产生;过氧化物酶活性随深度变化的趋势不明显,且在疏浚与未疏浚点显示相近水平,这种现象可能源于酶与腐殖质的结合;多酚氧化酶与过氧化物酶活性显著正相关,初步揭示了二者在有机质降解与腐质化过程中的偶联;细菌和放线菌(而非真菌)似为酶的主要生产者。并讨论了氧化还原酶在湖泊富营养化过程中的作用。
The enrichment of organic matter is a striking feature of lake eutrophication. However, distribution of organic matter associated with extraeellular enzymes （especially oxidoreduetases） in sediments is inadequately studied. In this paper, we described the distributions of oxidoreduetase activities in shallow lakes to reveal their roles in the degradation of organic matters in sediments and the effects on eutrophication. The spatial distribution of polyphenol oxidase and peroxidase in sediments of nine lakes （Lake Luhu, Lake Liangzi, Lake Houguan, Lake Niushan, Lake Sanjiao, Lake Longyang, Lake Moshui and Lake Yuehu in Hubei Province and Lake Taihu in Jiangsu Province） in the middle and lower reaches of the Yangtze River were studied and their correlations with microorganisms were also analyzed. The activities of the two enzymes studied among and within the lakes were unevenly distributed, the sediments with the significantly higher contents of organic matter showed the higher activities, which were observed in the inlet of waste water discharge,the zone with plant residues and the undredged sites. Vertically polyphenol oxidase activities were high at surface sediment with higher organic matter contents. Hence, the organic matters derived from the different sources could induce enzymes. The peroxidase activities varied slightly with increasing sediment depth, a result similar in the dredged and undredged areas, which was probably due to the formation of humie-enzyme complex by the peroxidase and humus after the enzyme induction. There was a significantly positive correlation between the activities of polyphenol oxidase and peroxidase, therefore, the two enzymes coupled in the process of decomposition of organic matters and humifieation. Bacteria and Aetinomyees （not fungi） were dominant species and may be the main producers of the enzymes. In short, the sediment of eutrophic Lakes would respond to the organic matters enrichment by shaping numbers and compositions of microorganisms （ Bacteria and Aetinomyees） and inducing polyphenol oxidase and peroxidase that oxidize organic matters to produce the humus in the end. At the same time, the enzyme could be stabilized by the formation of humie-enzyme complex. The multiple roles of oxidoreduetases in the process of lake eutrophication were discussed in the paper. It may accelerate the process of eutrophication by promoting anaerobic inorganic phosphorus release because of oxygen consumption by polyphenol oxidase, forming loose detritus layer to restrict submerged maerophyte restoration, and affecting division and growth of cell to cause algae bloom. On the other hand, it may combat eutrophication process through immobilizing nutrient substances such as amino acids and polysaeeharides by humus and inhibiting activity of alkaline phosphatase and nitrification, thereby, it delaying phosphorus and nitrogen cycling. Meanwhile, the formation of humie-enzyme complex may sustain the activities mentioned above. In conclusion, the process of enzymatic decomposition of organic matter in lake sediment is complicated,and the underlying mechanisms should be studied further more.
出处
《水生生物学报》
CAS
CSCD
北大核心
2008年第3期345-353,共9页
Acta Hydrobiologica Sinica
基金
中国科学院知识创新工程重要方向项目(KZCX2-YW-426)
国家“十五”重大科技专项(2002AA601021、2002AA601013)项目资助
