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雪被斑块厚度对川西岷江冷杉林土壤有机层可培养细菌关键生理类群的影响

Effects of Snow Thickness on Several Cultivable Bacterial Physiological Groups in the Soil Organic Layer under an Alpine Forest at Later Freezing-thawing Season

  • 摘要: 全球气候变化正在影响高寒地区雪被格局,不同厚度雪被斑块可能通过影响土壤温度和湿度强烈作用于土壤微生物群落结构,进而影响微生物驱动的土壤生态过程,但缺乏必要关注。研究采用稀释平板法和最大或然数法,分析了川西高山典型岷江冷杉(Abies faxoniana)原始林季节性冻融末期林内天然形成的不同厚度雪被斑块下土壤有机层可培养细菌及其关键生理类群数量特征。结果表明:高山森林季节性冻融末期雪被厚度显著影响土壤有机层可培养细菌及其生理类群的结构和数量特征,而且不同土壤层次可培养细菌及其生理类群对雪被厚度的响应存在明显的差异。总体而言,氨化细菌、硝化细菌和嫌气性纤维素分解菌数量在厚型雪被下数量相对较高,反硝化细菌数量随雪被厚度增加而降低,而好气性纤维素分解菌数量受雪被厚度影响较小。季节性冻融末期,高山森林有机层细菌生理类群在不同雪被斑块下总体上数量变化趋势均表现为:氨化细菌>反硝化细菌>硝化细菌>好气纤维素分解菌>嫌气纤维素分解菌。本研究为深入认识气候变化背景下高山森林土壤生态过程的季节转化提供了重要的理论和科学依据。

     

    Abstract: Global climate change is affecting the alpine snow cover pattern. In this context, different snow depths of natural snow patches surely will affect soil temperature and humidity strongly, which retained strong effects on the soil microbial community structure and microbial activity. However limited information is available on soil ecological process driven by microorganisms and what will come of this process under the effects of these complex factors have not demonstrated. The effects of snow thickness on the characteristics of cultivable bacteria and bacterial physiological groups in the soil organic layer of Abies faxoniana forest were studied by using the plate culture method and the most probable number method, which have been used widely in measuring numbers of specific microbial physiological groups. Snow thickness significantly influenced the numbers of bacteria and its physiological groups in the organic layer, while in the every soil layer, there is obvious difference respond between the snow cover and the bacteria and its physiological groups. In general, the numbers of ammonifying bacteria, nitrifying bacteria and anaerobic cellulose decomposing bacteria are relatively more under the thickest snow patch than under the other patches. With the deepening of snow thickness, the number of denitrifying bacteria reduced. Meanwhile, aerobic cellulose decomposing bacteria number showed no significantly changes. The overall trend for the numbers of bacterial physiological groups was: ammonifying bacteria > denitrifying bacteria > nitrifying bacteria > aerobic cellulose decomposing bacteria > anaerobic cellulose decomposing bacteria. The results provides important theoretical and scientific basis for understanding the seasonal transition of soil ecological process in the alpine forests under climatic backgrounds.

     

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