不同沉水植物净水能力与植株体细菌群落组成相关性

选取苦草(Vallisneria natans)、密刺苦草(Vallisneria denseserrulata)、黑藻(Hydrilla verticillata)、伊乐藻(Elodea canadensis)、金鱼藻(Ceratophyllum demersum)、竹叶眼子菜(Potamogeton malaianus)、篦齿眼子菜(Potamogeton pectinatus)和微齿眼子菜(Potamogeton maackianus)这8种亚热带地区常见的沉水植物为研究对象,在室内静水条件下对其氮、磷吸收和水质净化能力进行对比试验,并结合16S rRNA基因测序对沉水植物关联细菌群落组成进行测定,研究沉水植物对水体的净化能力与植株体菌群之间的相关性.结果表明,8种沉水植物对水体中的氮磷的去除主要通过植物增效作用,植物吸收富集作用去除率较低.其中密刺苦草对水体中TN、TP的去除率最高,达到了91. 58%和96. 81%.伊乐藻、金鱼藻对水中氮磷自身吸收能力高于其他组,密刺苦草和苦草的植物增效的净化能力最强.经分析,8种沉水植物对水体中氮磷的净化能力较强可能是因为植物关联的细菌大多具有降解作用.根瘤菌目(Rhizobiales)、伯克霍尔德氏菌目(Burkholderiales)、黄杆菌目(Flavobacteriales)、产碱杆菌科(Alcaligenaceae)、贪铜菌属(Cupriavidus)和芽孢杆菌属(Bacillales)的细菌可能是引起密刺苦草增效的净化能力较强的优势菌群,异常球菌纲(Deinococci)、丛毛单胞菌科(Comamonadaceae)、腐螺旋菌科(Saprospiraceae)和生丝微菌属(Hyphomicrobium)的细菌可能是引起苦草增效的净化能力较强的优势菌群.

Correlation Between Water Purification Capacity and Bacterial Community Composition of Different Submerged Macrophytes

Eight submerged macrophytes are commonly found in subtropical areas, including Vallisneria natans, Vallisneria denseserrulata, Hydrilla verticillata, Elodea canadensis, Ceratophyllum demersum, Potamogeton malaianus, Potamogeton pectinatus, and Potamogeton maackianus, and these eight macrophytes were selected as research objects. The absorption capacity of nitrogen and phosphorus and water purification ability of submerged macrophytes were compared under indoor static water conditions. Furthermore, combining the bacterial community composition of submerged macrophytes, which was determined by 16S rRNA gene sequencing, the correlation between the water purification ability and the bacterial community of submerged macrophytes was determined. The results showed that all of the submerged macrophytes had obvious purification effects on nitrogen and phosphorus in water. The removal of nitrogen and phosphorus by submerged macrophytes was mainly through plant synergism, and the removal rate of plant absorption and enrichment was low. Among them, the removal rate of nitrogen and phosphorus was the highest in Vallisneria denseserrulata, reaching 91.58% and 96.81%. The self-absorption ability of nitrogen and phosphorus from water of Elodea canadensis and Ceratophyllum demersum was higher than other groups. The plant synergistic purification ability of Vallisneria denseserrulata and Vallisneria natans was the highest. The absolute dominant phyla of eight submerged macrophyte-associated bacteria were Proteobacteria (abundance values were more than 40%). At the genus level, Cupriavidus, Rhodobacter, and Gemmatimonas were the dominant genera for different submerged macrophytes. Most of these bacterial groups were degradable, which may be the main reason for the strong ability of eight submerged macrophytes to purify nitrogen and phosphorus in the water. The LEfSe analysis showed that Vallisneria denseserrulata and Vallisneria natans had the highest number of bacteria with significant differences. Among them, Rhizobiales, Burkholderiales, Flavobacteriales, Alcaligenaceae, Cupriavidus, and Bacillales may be the dominant bacteria to enhance the efficiency of plant purification of the water by Vallisneria denseserrulata. The bacteria of Deinococci, Comamonadaceae, Saprospiraceae, and Hyphomicrobium may be the dominant bacteria to enhance the efficiency of plant purification of the water by Vallisneria natans.