黑土微生物呼吸及群落功能多样性对温度的响应

Responses of black soil's microbial respiration and community functional diversity to temperature

采用室内培养法,研究了梨树(43°20′N,124°28′E)、德惠(44°12′N,125°33′E)、海伦(47°26′N,126°38′E)和北安(48°17′N,127°15′E)黑土在4℃、15℃和28℃培养条件下的土壤微生物呼吸及Biolog代谢功能多样性.呼吸试验结果表明:尽管土壤微生物呼吸速率在不同培养温度下均表现为北安>海伦>德惠>梨树,但呼吸温度敏感性(Q10值)却随培养温度不同而产生分异,在4℃到15℃变化区间,梨树、德惠、海伦和北安土壤的Q10平均值分别为2.72、3.26、3.21和3.74,而在15℃到28℃变化区间,Q10平均值分别为3.29、2.36、2.11和1.79.不同样点土壤微生物呼吸熵(qCO2)也随培养温度不同而不同,qCO2值在28℃条件下为梨树>德惠>北安>海伦,在15℃条件下为北安>德惠>海伦>梨树,而在4℃条件下样点间变化不大.Biolog试验结果表明:在4℃条件下,微生物群落底物利用碳源数和代谢Shannon指数以海伦和北安黑土较高,而在15℃和28℃条件下,则以梨树和德惠黑土较高.主成分分析表明,海伦与北安、德惠与梨树之间的微生物群落代谢功能相似性较高.综上,不同纬度黑土微生物呼吸特征及群落功能多样性存在差异,高纬度黑土对低温变化敏感,而低纬度黑土对高温变化敏感.

Black soil samples were collected from Lishu （43°20＇ N,124°28＇ E）,Dehui （44°12＇ N,125°33＇ E）,Hailun （47°26＇ N,126°38＇ E）,and Bei＇an （48°17＇ N,127°15＇ E）,and an incubation test was conducted to study their microbial respiration and Biolog metabolic functional diversity at 4 ℃,15 ℃,and 28 ℃. The soil microbial respiration rate was in the order of Bei＇an Hailun Dehui Lishu,irrespective of incubation temperature,but the sensitivity of the respiration to the temperature,i.e.,Q10 value,differed. The average value of the Q10 for the soils from Lishu,Dehui,Hailun,and Bei＇an was 2.72,3.26,3.21,and 3.74 in the range of 4 ℃-15 ℃,and was 3.29,2.36,2.11,and 1.79 in the range of 15 ℃ to 28 ℃,respectively. The metabolic quotient （qCO2） also differed with incubation temperature,which was in the order of Lishu Dehui Bei＇an Hailun at 28 ℃ and of Bei＇an Dehui Hailun Lishu at 15 ℃,but no significant difference was observed at 4 ℃. Biolog test showed that the substrate richness and metabolic Shannon diversity index of microbial community were higher for the soils from Hailun and Bei＇an at 4 ℃,but higher for those from Lishu and Dehui at 15 ℃ and 28 ℃. Principal component analysis with Biolog data suggested that the metabolic function of soil microbial community was similar between Bei＇an and Hailun,and between Dehui and Lishu. In sum,the responses of black soil＇s microbial respiration and community functional diversity to temperature varied with latitude,i.e.,more sensitive to low temperature in high latitude region,but more sensitive to high temperature in low latitude region.