Abstract Ectomycorrhizal (ECM) fungi form a symbiotic association with host trees, functionally promoting the nutrient uptake in the hosts via their secretion of enzymes to degrade organic compounds. Because of the involvement in nutrient cycling, ECM fungi are important to the establishment of host trees and forest recovery. In Thailand, ECM fungi are mostly associated with host tree species in the Dipterocarpaceae found in deciduous dipterocarp forests (DDFs), some of which are secondary forests naturally recovering after abandonment of logging and agriculture. To determine the function of ECM fungi in secondary DDFs, temporal changes in the ECM community structure and potential activities of three enzymes involved in nitrogen, carbon, and phosphorus cycling (β-N-acetylglucosaminidase, β-glucosidase, and acid phosphatase) from ECM roots and soils were investigated in two secondary DDF fragments in the Saraburi and Nan provinces of Thailand. A total of 180 soil samples from each forest were collected at four times across the wet and dry seasons from June 2015 to May 2016. Soil moisture content, total nitrogen, organic matter, and available phosphorus contents were measured. The results showed temporal changes in the ECM fungal communities and relative enzyme activities throughout the study period, although differences between the wet and dry seasons were not detected. The enzyme profiles associated with ECM roots were significantly correlated to the ECM communities in both DDFs. Moreover, the total nitrogen and soil moisture content influenced the temporal variation of ECM and soil enzyme profiles. These findings suggest the effect of edaphic factors combined with the ECM communities on their enzyme activities in secondary DDFs in Thailand.

中文翻译：

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次生落叶龙脑香林碎片外生菌根和土壤相关酶活性的时间变化

摘要 外生菌根 (ECM) 真菌与寄主树木形成共生关系，通过分泌酶降解有机化合物，在功能上促进寄主对养分的吸收。由于参与养分循环，ECM 真菌对寄主树木的建立和森林恢复很重要。在泰国，ECM 真菌主要与在龙脑香落叶林 (DDF) 中发现的龙脑香科的寄主树种有关，其中一些是在放弃伐木和农业后自然恢复的次生林。为了确定 ECM 真菌在次生 DDF 中的功能、ECM 群落结构的时间变化以及参与氮、碳和磷循环的三种酶（β-N-乙酰氨基葡萄糖苷酶、β-葡萄糖苷酶、来自 ECM 根和土壤的酸性磷酸酶和酸性磷酸酶）在泰国北武里和难府的两个次生 DDF 片段中进行了研究。从 2015 年 6 月到 2016 年 5 月，在 2015 年 6 月至 2016 年 5 月的干湿季节分四次收集了来自每片森林的 180 个土壤样品。测量了土壤水分含量、总氮、有机质和有效磷含量。结果显示整个研究期间 ECM 真菌群落和相对酶活性的时间变化，尽管未检测到干湿季节之间的差异。与 ECM 根相关的酶谱与两个 DDF 中的 ECM 群落显着相关。此外，总氮和土壤水分含量影响 ECM 和土壤酶谱的时间变化。