[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(pp+/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(ppα-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。

历经4a(1992～1995年)定位研究表明:试区林网内无叶期的防风效能为39%～40%,着叶期为55.8%～56.2%。气温降低0.6～0.8℃,最热月(7月)尤为明显,平均降低1.2℃,蒸发量降低24.3%～24.7%,相对湿度提高8%～15%。干热风发生天数减少58.8%,其中轻型减少33.3%,重型减少87.5%。在林网保护下,作物产量提高5.14%,玉米纯增产量468km/hm2。纯增产值655.2元/hm2,与无林网农田相比,增产效果显著,平均提高了50%～100%。

The Castanopsis sclerophylla seed length, seed diameter, seed length× seed diameter, seed length/seed diameter and hundred grain weight from nine areas were studied. The results showed that extremely significant difference were found in seed characters of C. sclerophylla from different areas. The most coefficient of variation is hundred grain weight and the least is seed length/seed diameter. Correlation analysis showed that the seed length and seed diameter had the significant positive correlation with hundred grain weight; seed became bigger and heavier as latitude became lower, the annual average temperature and frost free period become longer; the hundred grain weight had significant positive correlation with rainfall, seed length/seed diameter had significant negative correlation with the rainfall, And clustering analysis showed that phenotypic variation was basicaly continuous variation with the geography, which was consistent with the result of relevant analysis.

Soil samples were collected to a depth of 20 cm using a 3.0 m×3.0 m grid in 900 m2(30.0 m×30.0 m) plots for analysis of spatial patterns of soil in undisturbed area of China fir (Cunninghamia lanceolata) and Masson pine(Pinus massoniana) mixed forest in the Three Gorger Reservoir Areas. The investigation data showed that the average of soil DNA content was 922.71 μg·g-1 water-free soil, the maximal value was 6 761.30 μg·g-1 water-free soil, and the less value 58.52 μg·g-1 water-free soil. The geostatistical analysis indicated that the spatial distribution characteristic was not obviously reflected by the liner graphs while samples were randomly distribution and independent each other. The separation distance among samples was related to precision of soil DNA content, the effects of non-structure factors (environment factors, disturbed factors) on spatial correlation structure would disappeared due to the separation distance in excess of 18.84 m, and the spatial correlation of soil DNA faded down in plots. Spatial variability in soil DNA in the region was mostly contributed by the influencing factors including soil nitrogen, soil organic matter and content of soil water.