葡萄糖和不同数量氮素供给对黑土氨基糖动态的影响

EFFECT OF GLUCOSE AND NITROGEN SUPPLY ON DYNAMICS OF AMINO SUGARS IN MOLLISOL

通过室内培养实验探讨了葡萄糖及不同数量的NH4+施入对土壤中三种氨基糖(氨基葡萄糖、氨基半乳糖和胞壁酸)动态的影响,同时利用氨基葡萄糖和胞壁酸的比值探讨了微生物在养分固持过程中的相对贡献。结果表明,土壤氨基糖数量受到外加碳源和养分的显著影响,且其变化各有特征。胞壁酸受养分影响最为显著,可在一定程度上调节并平衡碳氮元素的供给与需求;氨基葡萄糖稳定性高于胞壁酸,但在碳源极度缺乏时也可分解;养分状况对氨基半乳糖的影响并不显著。碳源是促进土壤微生物氮素固持的关键因子,在活性碳源存在下,相对丰富的氮素供给有利于细菌的快速生长,而碳源相对充足时则有利于真菌的快速增殖。

Effect of application of NH4＋ and glucose on dynamics of three kinds of amino sugars （glucosamine, galaetosamine and muramie acid） in mollisol was investigated through laboratory incubation. Relative contribution of microbial communities to nutrient immobilization was explored in relation to the ratio of glucosamine and muramic acid. Results show that contents of the soil amino sugars were influenced evidently to a various extent by the extraneous glucose and NH4. Concentration of muramie acid was significantly affected by the substrate added, regulating and balancing supply and demand of carbon or nitrogen to a certain extent. Glucosamine was more stable than muramic acid and subject to de- composition in the case of extreme carbon deficiency. No significant effect of soil nutrient status on galactosamine was ob- served. Carbon application was important to improve nitrogen fixation by soil microbes. In the presence of activated carbon sources, relatively rich nitrogen supply benefited rapid growth of bacteria, while relatively sufficient carbon sources did fast propagation of fungi.