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[目的]研究森林沼泽演替与火干扰条件下土壤微生物结构与多样性变化,为进一步揭示土壤微生物群落在森林沼泽保护与恢复中的作用提供依据。[方法]采用磷脂脂肪酸法与BIOLOG方法,研究大兴安岭南瓮河国家自然保护区内主要森林沼泽类型(兴安落叶松-狭叶杜香-藓类沼泽、兴安落叶松-兴安杜鹃-藓类沼泽、兴安落叶松+白桦-苔草沼泽)与2006年受不同火强度干扰沼泽(重度火烧的兴安落叶松-兴安杜鹃-藓类沼泽和中度火烧的兴安落叶松+白桦-苔草沼泽)土壤微生物群落特征,探讨沼泽主要发育阶段与火干扰强度对土壤微生物群落的影响。[结果]研究区域土壤微生物群落以16:00(16.29±5.62 nmol·g-1)、甲烷氧化菌(18:1ω8t)(9.89±8.61 nmol·g-1)与16:1ω7c(9.79±3.24 nmol·g-1)的微生物为优势种群。土壤微生物总PLFAs含量、革兰氏阳性菌(G+)中a15:0、i16:0、i17:0、革兰氏阴性菌(G-)中的cy19:0、真菌中的18:2ω6c、甲烷氧化菌(18:1ω8t)与森林沼泽发育阶段、火干扰明显相关(p<0.05)。一般饱和直链脂肪酸/单烯饱和脂肪酸比(Sat/Mon)偏低,其比值随沼泽发育呈现增加趋势,受到火干扰后明显增加(p<0.05);真菌/细菌比(F/B)与革兰氏阳性菌/革兰氏阴性菌(G+/G-)未随着沼泽发育呈现出规律性变化,其比值受火干扰后明显发生改变(p<0.05)。土壤细菌与真菌对6类碳源的利用能力明显不同(p<0.001),其中土壤细菌对α-D-Lactose与L-Threonine利用存在差异性(Fα-D-Lactose=2.87 p=0.080,FL-Threonine=3.00 p=0.078),土壤真菌对D-Mannitol、D-glucosaminic Acid利用存在差异性(FTween 80=2.75,p=0.088,FD-Mannitol=3.53 p=0.047,FD-glucosaminic Acid=4.67 p=0.022),但沼泽类型与火干扰未对土壤微生物功能多样性产生影响(p>0.05)。[结论]土壤微生物量与沼泽发育阶段相关;沼泽发育与火干扰改变土壤微生物群落结构。土壤细菌与真菌对碳源利用方面具有选择性。
[Objective] The study aimed to study the changes of soil microbial structure and diversity under the condition of forest swamp succession and fire disturbance, and provide basis for further revealing the role of soil microbial community in the protection and restoration of forest swamps. [Method] Phospholipid fatty acid method and BIOLOG method were used to study the main forest swamp types (Larix gmelinii-Phyllostachys pubescens-moss swamp, Xingan larch-Xingan azalea-moss swamp, Larix gmelinii + Betula platyphylla - Carex marsh) and in 2006 by different fire intensity interference swamp (heavy fire Larix Larix - Xingan azalea - moss swamp and moderate fire Larix gmelinii + birch - Carex swamp) soil microorganisms Community characteristics of the marsh to discuss the main stages of development and intensity of fire disturbance on soil microbial community. [Result] The soil microbial community in the study area was characterized by 16:00 (16.29 ± 5.62 nmol · g-1), methanotrophic bacteria (9.89 ± 8.61 nmol · g-1) and 16: 1ω7c · G-1) of the micro-organisms as the dominant population. Total PLFAs in soil microorganisms were a15: 0, i16: 0, i17: 0 in Gram-positive bacteria (G +), cy19: 0 in Gram- negative bacteria (G-), 18: 2ω6c in fungi Oxidative bacteria (18: 1ω8t) correlated significantly with fire disturbance at the stage of forest swamp development (p <0.05). (Sat / Mon) was lower than that of saturated fatty acids / saturated fatty acids (Sat / Mon), and the ratio increased with the development of marsh. The ratio of F / B and F / Gram-positive bacteria / Gram-negative bacteria (G + / G-) showed no regular change with the development of marsh, and the ratio changed obviously after fire disturbance (p <0.05). Soil bacteria and fungi had significantly different ability to utilize 6 kinds of carbon sources (p <0.001), and there were differences in the utilization of α-D-Lactose and L-Threonine among soil bacteria (Fα-D-Lactose = 2.87 p = 0.080, FL -Threonine = 3.00 p = 0.078). There were differences in soil fungi utilization of D-Mannitol and D-glucosaminic Acid (FTween 80 = 2.75, p = 0.088, FD-Mannitol = 3.53 p = = 0.022). However, marsh type and fire disturbance had no effect on functional diversity of soil microorganisms (p> 0.05). [Conclusion] The soil microbial biomass was related to the stage of marsh development. Swamp development and fire disturbance changed the soil microbial community structure. Soil bacteria and fungi have a selective carbon source.