无瓣海桑和秋茄人工林下土壤微生物群落研究

对2 a生单种无瓣海桑(Sonneratia apetala)、单种秋茄(Kandelia obvata)和混种无瓣海桑—秋茄(1:1)人工林下土壤理化性质、微生物群落结构、酶活性进行了研究.结果表明,单种无瓣海桑林下土壤pH值最低(5.61±0.08),土壤有机质、总磷、总氮含量在3个群落间均无显著差异;单种无瓣海桑林下土壤蛋白酶、芳基硫酸酯酶和磷酸酶的活性高于其它两种人工林,脲酶、纤维素酶和脱氢酶活性以混种林下最高(分别为190.20±28.49,19.04±4.77和93.21±14.10μg·g-1·h-1),β-葡萄糖苷酶和芳基硫酸酯酶活性在3种人工林下差异不显著;单种无瓣海桑林下土壤中各种脂肪酸含量较高,混种林下土壤的脂肪酸含量最低;典型相关分析表明,蛋白酶活性和土壤pH、总氮含量呈显著负相关(P<0.01),磷酸酶活性与总磷含量呈显著正相关(P<0.01).

Study on Soil Microbial Community Characteristics of Sonneratia apetala and Kandelia obvata Plantations in Shenzhen Bay

The present study examined the relationships between soil physical and chemical properties, soil microbial community structure (expressed by phospholipid fatty acids, PLFAs) and enzymatic activities in 3 types of 2-year-old plantations, which were monoculture Sonneratia apetala, monoculture Kandelia obvata and mixed plantations (with 50% of S.apetala and 50% ofK.obvata) in Futian National Nature Reserve, Shenzhen Bay. Soil in mono-S.apetalawas most acidic (pH-value 5.61±0.08), while the organic matter content, total phosphorus content (P) and the total nitrogen (N) content showed no significant difference among three plantations. Soil in the mono-S.apetalashowed higher activities of protease, arylsulphatase, phosphatase among three plantations, and the mixed plantations had highest urease, cellulose, and dehydrogenase activities which were 190.20±28.49, 19.04±4.77 and 93.21±14.10 μg·g-1·h-1, respectively. However, no significant difference was found in the activities ofβ-glucosidase and arylsulphatase among three plantations. The diagnostic PLFAs were the most abundant in the mono-S.apetala,but the least in the mixed plantation. The canonical correlation analysis revealed that protease activities were significantly negatively correlated to pH-value and the content of total N, while the phosphatase showed significant positive correlation with the content of total P.