| 菹草茎叶附着细菌与周围环境中细菌群落结构及功能差异分析 |
| 摘要点击 1226 全文点击 183 投稿时间：2023-11-22 修订日期：2024-03-19 |
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| 中文关键词 沉水植物 淡水 细菌 多样性 功能 |
| 英文关键词 submerged macrophytes fresh water bacteria diversity function |
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| 中文摘要 |
| 沉水植物整个植株生长于水面以下,其茎叶等组织可为水体浮游细菌定植提供良好的生物载体,促使细菌大量附着并与沉水植物共生,成为水生态系统的重要组成部分之一. 为进一步了解沉水植物茎叶附着细菌群落结构及其功能特征,以优势沉水植物菹草为研究对象,采集菹草茎叶组织以及上覆水和沉积物等环境样品,对比分析菹草茎叶附着细菌及其植物所处水域水体浮游细菌及沉积物细菌群落及其功能差异. 结果表明,3种来源样品总共检测OTUs共10 320个,包含64门、189纲、448目、721科和1 366属. 沉积物细菌群落丰富度以及多样性最高,其次为植物茎叶附着细菌,水体浮游细菌Alpha多样性指数最低,3种来源样品Alpha多样性4个指数间均存在显著差异（P<0.05）. 相同来源样品的细菌群落结构相似度较高,而不同来源样品细菌群落结构呈显著性差异（P<0.05）,反映出上覆水、沉积物以及菹草茎叶附着细菌各自形成复杂而独特的群落结构. 门、目以及属分类水平上,3种来源样品大部分优势细菌类群、非优势类群以及偶见类群相对丰度存在显著差异（P<0.05）. 变形菌门、放线菌门和拟杆菌门是共有优势细菌门,而厚壁菌门则是植物茎叶附着细菌特有优势门. 碳水化合物代谢、能量代谢、氨基酸代谢、辅因子和维生素代谢等在3种样品中存在显著差异（P<0.05）；菹草茎叶样品中化能异养型和需氧化能异养功能类型相对丰度高于水和沉积物样品. 沉积物样品中具有更高的硝酸盐还原、氮呼吸和硝酸呼吸功能. 综上,沉水植物茎叶表面积可促使细菌附着,形成独一无二的植物茎叶附着细菌群落；菹草及其周围水体及沉积物在营养元素的生物地球化学循环过程中发挥了不同的潜力. |
| 英文摘要 |
| The stems and leaves of submerged macrophytes usually grow below the water surface and could provide a good biological carrier for the colonization and growth of planktonic bacteria in water. Therefore, attached bacteria on the stem and leaf surfaces of submerged macrophytes are important components and play a crucial role in aquatic ecosystems. To further understand the structure characteristics and functional differences of the bacterial community attached to the stems and leaves of submerged macrophytes, the submerged macrophytes Potamogeton crispus and the overlying water and sediment were sampled and analyzed in this study. The results showed that a total of 10 320 OTUs were detected in the P. crispus samples, the overlying water samples, and the sediment samples. These OTUs included 64 phyla, 189 classes, 448 orders, 721 families, and 1 366 genera. The richness and diversity of bacterial communities in sediments were the highest, followed by the stem and leaves of P. crispus, and the alpha diversity index of planktonic bacteria in water was the lowest. Significant differences （P<0.05） were observed among the four alpha diversity indices of the three source samples. Bacterial communities with greater similarity were obtained from the same source samples, but there was more distinct community composition dissimilarity in bacteria collected from the submerged macrophytes and the overlying water and sediment samples （P<0.05）. At the level of phylum, order, and genus classification, the relative abundance of most dominant bacterial species, non-dominant species, and occasional species showed significant differences among the three source samples （P<0.05）. Proteobacteria, Actinobacteria, and Bacteroidetes were common dominant bacterial phyla for the three source samples, while Firmicutes were unique dominant phyla for attachment bacteria on the plant stem and leaves of P. crispus. There were differences in carbohydrate metabolism, energy metabolism, amino acid metabolism, cofactors, and vitamin metabolism among the three source samples （P<0.05）. The relative abundance of chemical heterotrophic and oxidative heterotrophic functional types in the stem and leaf samples of P. crispus was higher than that in the overlying water and sediment samples. In addition, higher nitrate reduction, nitrogen respiration, and nitric acid respiration functions were observed in sediment samples. To summarize, the stems and leaves have the potential to encourage bacterial colonization and create a unique bacterial community on the surface of submerged macrophytes. Submerged P. crispus macrophytesand their surroundings （water and sediment） play different roles in the biogeochemical cycling of nutrients in the freshwater ecosystem. |
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