摘要
采用13CO(NH2)2为底物进行黑土培养实验,利用气相色谱/质谱技术测定土壤中三种氨基糖含量以及同位素富集比例,根据其微生物标识物作用探讨土壤中不同微生物群落对于尿素碳的同化利用特征及黑土氨基糖库对于尿素添加的响应。研究结果表明,尿素碳可以被土壤微生物同化利用,但是可利用性显著低于葡萄糖。氨基葡萄糖中13C富集比例显著高于胞壁酸,表明真菌对尿素碳的同化能力高于细菌。尿素添加使土壤有机碳含量有所下降,同时土壤氨基糖总量及其与有机碳的相对比例也显著降低,说明在碳源严重受限条件下,氨基糖可被优先分解利用以补充碳源供给。胞壁酸含量虽低,但其调节并平衡碳氮元素供给与需求的能力较强;氨基葡萄糖稳定性高于胞壁酸,但在碳源缺乏时也可部分分解。土壤氨基糖的动态与土壤碳氮的可利用性及其耦合作用密切相关,在平衡土壤碳氮需求方面具有一定的调节作用。
Mollisol samples were incubated indoors with 13CO (NH2)2 as substrate to investigate transformation of urea-carbon into soil amino sugar and its effect on dynamics of amino sugar pool. Contents of the three types of amino sugars (glucosamine, galactosamine and muramic acid) and their enrichments of 13C were measured with gas chromatography/mass spectrometry. On such a basis, specific utilization of urea-carbon by different microbial communities was evaluated. Results show that urea-carbon might be assimilated by soil microorganisms, but was significantly lower in availability than glucose-carbon. A higher amount of 13C was found in glucosamine than in muramic acid, suggesting that fungi are more capable of assimilating urea-carbon than bacteria. Application of urea decreased soil organic carbon content to some extent and at the same time significantly lowered the total amino sugar and its relative proportion in soil organic carbon, indicating that in severe shortage of carbon sources, amino sugars would be the priority carbon source to be decomposed to make up the carbon supply. Although murarnic acid was very low in concentration, it was highly capable of regulating and balancing carbon budget. Glueosamine was more stable than muramic acid, but decomposition of some of it was found in shortage of other carbon sources. As a whole, the dynamics of amino sugars is closely associated with the availability of soil carbon sources and their coupling effect, thus playing an important role in regulating supply and requirement of carbon and nitrogen in soil.
出处
《土壤学报》
CAS
CSCD
北大核心
2011年第6期1189-1195,共7页
Acta Pedologica Sinica
基金
国家自然科学基金面上项目(40871149
41071161)
关键词
尿素碳
氨基糖
转化
微生物利用
黑土
Urea-carbon
Amino sugars
Transformation
Microorganism utilization
Mollisol