连续3年(2015-2018年)研究了珠江三角洲滨海红树林湿地、芦苇湿地、碱蓬湿地和互花米草湿地土壤微生物群落多样性及其影响因素。结果 表明:土壤pH基本表现为互花米草湿地>碱蓬滩湿地>芦苇湿地>红树林湿地,其中不同湿地植物群落土壤pH值差异均不显著(p>0.05); 土壤有机碳、全氮、全钾基本表现为互花米草湿地<碱蓬滩湿地<芦苇湿地<红树林湿地。滨海湿地不同植物群落土壤微生物碳源利用(AWCD)总体上呈逐渐增加的趋势,在培养24～72 h内AWCD快速增长,72 h后增长缓慢,192 h后急剧增长; 相同时间土壤微生物碳源利用大致表现为互花米草湿地<碱蓬滩湿地<芦苇湿地<红树林湿地,局部有所波动。碳水化合物和羧酸类碳源是滨海湿地不同植物群落土壤微生物的主要碳源,其次为氨基酸类、酚酸类和聚合物类,胺类碳源的利用率最小。土壤微生物群落的物种丰富度指数(H)、均匀度指数(E)、优势度指数(Ds)和碳源利用丰富度指数(S)基本表现为互花米草湿地<碱蓬滩湿地<芦苇湿地<红树林湿地,其中优势度指数(Ds)差异均不显著(p>0.05)。主成分分析结果表明,具有较高相关性的碳源有18种,其中羧酸类化合物有5种,多聚化合物有3种,碳水化合物有6种,芳香化合物1种,氨基酸2种,胺类化合物1种,在主成分分离中起主要贡献作用的是胺类和氨基酸类碳源。相关性分析显示,土壤养分和pH与微生物群落功能多样性密切相关,其中pH对土壤微生物群落功能多样性贡献为负,土壤养分对土壤微生物群落功能多样性贡献为正,是滨海湿地不同植物群落土壤微生物群落多样性差异的重要影响因素。
In order to study the variation of soil microbial community diversity and its influencing factors in coastal wetland from 2015—2018, mangrove wetland, reed wetland, salicornia wetland and mutual flower rice grass wetland were selected to explore soil microbial community diversity and its influencing factors. The results showed that the basic soil pH values decreased in the order: mangrove wetland>reed wetland>salicornia wetland>mutual flower rice grass wetland, and there was no significant difference in soil pH value between different wetland plant communities (p>0.05); soil organic carbon, total nitrogen and total potassium increased in the order: mangrove wetland<reed wetland<salicornia wetland<mutual flower rice grass wetland; the use of soil microbial carbon sources(AWCD)in different plant communities in coastal wetlands showed a gradually increasing trend on the whole, AWCD increased rapidly within 24 to 72 hours after cultivation, but slowly after 72 hours and sharply after 192 hours. At the same time, the uses of AWCD increased in the order: mangrove wetland<reed wetland<salicornia wetland<mutual flower rice grass wetland, with local fluctuations; carbohydrate and carboxylic acid carbon sources are the main carbon sources of soil microorganisms in different plant communities in coastal wetlands, followed by amino acids, phenolic acids and polymers, and amine carbon sources have the lowest utilization rate; the species richness index(H), evenness index(E), dominance index(Ds)and carbon source utilization richness index(S)of soil microbial community increased in the order: mangrove wetland<reed wetland<salicornia wetland<mutual flower rice grass wetland, with no significant difference in dominance index(Ds)(p>0.05). Principal component analysis results show that there is the high correlation among 18 kinds of carbon sources, among which there are five kinds of carboxylic acid compounds, 3 kinds of polymer compounds, 6 kinds of carbohydrates, 1 kind of aromatic compound, 2 kinds of amino acids, 1 kind of amine compound, amines and amino acids carbon source have main contribution to the separation of main component. Correlation analysis showed that soil nutrients and pH were closely related to the microbial community functional diversity, pH had the negative contribution to soil microbial community functional diversity, and soil nutrients had the positive contribution to soil microbial community functional diversity, which were the important influence factors on the differences of soil microbial community diversity in different plant communities in coastal wetland.
