Biodegradation kinetics of monosaccharides and their contribution to basal respiration in tropical forest soils
Biodegradation kinetics of monosaccharides and their contribution to basal respiration in tropical forest soils
复制标题
单糖的生物降解动力学及其对热带森林土壤基础呼吸的贡献
DOI：
10.1080/00380768.2011.623226
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发表时间：
2011
影响因子：
2
通讯作者：
Kosaki T
中科院分区：
文献类型：
--
作者：
Hayakawa C;Fujii K;Funakawa S;Kosaki T
土壤溶液中的低分子量有机物易被生物降解，并能促进土壤微生物的呼吸作用。我们的主要目的是利用14 C-放射性标记葡萄糖研究单糖的矿化动力学。基于这些数据和土壤溶液中单糖的浓度，我们评估了各种热带森林土壤中单糖对基础呼吸的贡献。此外，控制单糖矿化动力学的因素进行了研究，通过比较热带和温带森林土壤。单糖组成的平均5.2%至47.7%的土壤溶液中溶解的有机碳。它们的动力学参数（Vmax和KM）由一个单一的Michaelis-Menten方程描述，在热带土壤中变化很大，分别为11 ~ 152 nmol g−1h− 1和198 ~ 1294 µmol L− 1，在温带土壤中变化很大，分别为182 ~ 400 nmol g−1h− 1和1277 ~ 3150 µmol L− 1。在热带和温带土壤中，Vmax值随微生物生物量C的增加而增加，而Km值与土壤生物学或理化性质无关。Vmax值与微生物生物量C之间的正相关关系表明，微生物生物量C是调节热带和温带森林土壤Vmax值的重要因素。单糖的生物降解动力学表明，在土壤溶液浓度下，微生物对单糖的矿化能力远远超过其矿化速率。单糖在土壤溶液中迅速矿化，在这项研究中，他们的平均停留时间很短（0.4-1.9小时）在热带森林。在实际土壤溶液浓度下，单糖矿化率占基础呼吸的22-118%。可能是因为快速和连续的生产和消费的单糖，单糖矿化被证明是热带森林土壤，以及在温带和寒带森林土壤中的基础呼吸的主要部分。
Low molecular weight (LMW) organic compounds in soil solution are easily biodegradable and could fuel respiration by soil microorganisms. Our main aim was to study the mineralization kinetics of monosaccharides using14C-radiolabelled glucose. Based on these data and the soil solution concentrations of monosaccharides, we evaluated the contribution of monosaccharides to basal respiration for a variety of tropical forest soils. Further, the factors controlling the mineralization kinetics of monosaccharides were examined by comparing tropical and temperate forest soils. Monosaccharides comprised on average 5.2 to 47.7% of dissolved organic carbon in soil solution. Their kinetic parameters (VmaxandKM), which were described by a single Michaelis-Menten equation, varied widely from 11 to 152 nmol g−1h−1and 198 to 1294 µmol L−1for tropical soils, and from 182 to 400 nmol g−1h−1and 1277 to 3150 µmol L−1for temperate soils, respectively. The values ofVmaxincreased with increasing microbial biomass-C in tropical and temperate soils, while theKMvalues had no correlations with soil biological or physicochemical properties. The positive correlation betweenVmaxvalues and microbial biomass-C indicates that microbial biomass-C is an essential factor to regulate theVmaxvalues in tropical and temperate forest soils. The biodegradation kinetics of monosaccharides indicate that the microbial capacity of monosaccharide mineralization far exceeds its rate at soil solution concentration. Monosaccharides in soil solution are rapidly mineralized, and their mean residence times in this study were very short (0.4–1.9 h) in tropical forests. The rates of monosaccharide mineralization at actual soil solution concentrations made up 22–118% of basal respiration. Probably because of the rapid and continuous production and consumption of monosaccharides, monosaccharide mineralization is shown to be a dominant fraction of basal respiration in tropical forest soils, as well as in temperate and boreal forest soils.