原始红松林土壤理化及微生物碳代谢特征对生长季动态的响应

【目的】明确原始红松林内土壤微生物群落对碳源的利用、土壤理化性质的季节变化规律及差异机制,探讨原始红松林土壤理化及生物学特征对气象因子季节动态的响应。【方法】以小兴安岭典型的原始阔叶红松林为研究对象,分别于2015年5—10月生长季内采集0~10 cm和≥10~20 cm的表层土壤样品。采用Biolog-ECO微平板检测法和土壤理化性质的常规测定方法测定红松林内土壤微生物功能多样性及土壤理化指标。【结果】(1)研究样地的多项土壤理化指标在月份间差异显著。(2)在整个生长季内平均颜色变化率(AWCD)的变化趋势基本一致,均随着培养时间的延长而逐渐升高,培养168 h以后,AWCD增加幅度逐渐减弱;AWCD值和多样性指数在月份间差异显著;土壤微生物群落的代谢活性表现出明显的季节差异,并呈现一定的规律性,6月显著高于其他月份(P0.05)。(3)氨基酸类、多聚物类、碳水化合物类碳源是红松林土壤微生物群落利用的主要优势碳源类型;通过主成分分析(PCA)、聚类分析可将土壤微生物群落碳源代谢特征大致分为3簇,即5—6月、7月、8—10月;土壤微生物利用碳水化合物类、氨基酸类、羧酸类碳源的变化对季节最为敏感。(4)通过相关性分析发现,AWCD值和多样性指数与速效磷、速效钾、含水量和有效氮之间存在显著或极显著相关性;分类变异分析发现土壤理化性质变化是引起微生物功能多样性发生季节性变化的主要因子,其中含水量、速效磷的解释度分别为12.76%和30.71%。【结论】原始阔叶红松林土壤理化及微生物功能碳代谢特征具有显著的生长季动态变化,月降水总量变化的影响最为重要。

Responses of soil physicochemical properties and soil microorganism characteristics regareding as carbon metabolism in original Korean pine forest

Objective]Understand the seasonal variations and mechanisms of the differences in the soil microbial com?munity and soil physicochemical properties for a original Korean pine forest, and explore the seasonal changes in the soil physicochemical properties in response to meteorological factors.Method]The study site was located in Xiaoxing′an Mountain, a typical original broadleaf Korean pine forest, and the soil ( 0-10 cm and≥10-20 cm) was sampled from May to October in 2015. The soil microbial functional diversity and soil physicochemical properties were measured by using the Biolog microplate method and conventional measurement methods. Result] The soil physicochemical properties had significant differences in different months. The average well color development ( increased of AWCD) val?ue gradually with prolonged culture time;the increase of AWCD value gradually weakened after 168 hours. The AWCD values and microbial diversity were significantly different among months. The metabolic activity of the soil microbial com?munity had significant seasonal variation, and was the lowest in July and the highest in June ( P< 0.05) . Amino acids, polymers, and carbohydrates were the dominant carbon sources. The results of principal component analysis ( PCA)showed that the metabolic characteristics of soil microbial community carbon were divided into three clusters: May to June, July, and from August to October. The utilization of carbohydrates, amino acids and carboxylic acids were more sensitive to seasonal variations than that use of other carbon sources. The results of correlation analysis showed that AWCD value and microbial diversity indices had significant positive correlations with available P, available K, soil water content, and available N. Soil water content ( which explained 12.76% of the variance) , available P ( which explained 30.71%) were the main factors that affected the seasonal variation in microbial functional diversity according to variation partition analysis.Conclusion]The soil physicochemical properties and microbial functional carbon metabolism charac?teristics were significantly different during the growth season and the non?growth season in the original broadleaf Korean pine forest, and this was most significantly influenced by different precipitation in different months.