The turnover of carbohydrate carbon in a cultivated soil estimated by 13C natural abundances
The turnover of carbohydrate carbon in a cultivated soil estimated by 13C natural abundances
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DOI：
10.1111/j.1365-2389.2006.00811.x
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发表时间：
2006-08
影响因子：
4.2
通讯作者：
Delphine Derrien;C. Marol;M. Balabane;J. Balesdent
中科院分区：
文献类型：
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作者：
Delphine Derrien;C. Marol;M. Balabane;J. Balesdent
了解土壤有机质（SOM）的化学组成需要确定每一类化合物的动态。我们测量了碳在中性碳水化合物中的动态，通过使用天然13 C标记在实验小麦和玉米序列中延伸超过23年。通过三甲基硅烷基（TMS）衍生物的气相色谱/燃烧/同位素比质谱（GC/C/IRMS）测定水解粒度组分中单个中性单糖的同位素组成。根据单糖的不同，13 C/12 C比值的灵敏度在1 ‰和2 ‰之间。中性糖碳的年龄分布与土壤总碳的年龄分布非常相似。颗粒有机物（POM）的特点是植物来源的葡萄糖和木糖的优势。在POM> 200 µ m中，糖碳的平均年龄（5年）略小于总碳的平均年龄（7年）。木糖比葡萄糖年轻。0 - 50 µ m的精细级分主要含有葡萄糖、阿拉伯糖、半乳糖、木糖、岩藻糖和甘露糖，其主要来源于微生物。0 - 50 µ m组分中碳水化合物碳的平均年龄在60 - 100年之间，与总有机碳（OC）的年龄相似。不同单糖之间的碳年龄没有差异，50 - 200 µ m的POM组分具有中间特征和转换。考虑到碳水化合物的典型不稳定性，碳水化合物碳的相对较长的年龄可以解释为物理或化学保护降解，以及通过土壤微生物对土壤有机质碳的再循环。
Understanding the chemical composition of soil organic matter (SOM) requires the determination of the dynamics of each class of compounds. We measured the dynamics of carbon in neutral carbohydrates by use of natural 13C labelling in an experimental wheat and maize sequence extending over 23 years. The isotopic composition of individual neutral monosaccharides was determined in hydrolysed particle‐size fractions by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) of trimethylsilyl (TMS) derivatives. The sensitivity in terms of 13C/12C ratios ranged between 1 and 2‰ depending on the monosaccharide. The age distribution of neutral sugar carbon was very similar to that of total soil carbon. Particulate organic matter (POM) was characterized by the predominance of glucose and xylose of vegetal origin. In POM > 200 µm, the mean age of sugar‐C (5 years) was slightly less than that of total carbon (7 years). Xylose was younger than glucose. The fine fraction 0–50 µm contained mainly glucose, arabinose, galactose, xylose, fucose and mannose, which had predominantly microbial origins. The mean age of carbohydrate carbon in the fraction 0–50 µm was between 60 and 100 years and was similar to that of total organic carbon (OC). No difference in the age of carbon between the individual monosaccharides was found. The POM fraction 50–200 µm had an intermediate signature and turnover. Considering the typical lability of carbohydrates, the relatively great age of carbohydrate carbon may be explained by physical or chemical protection from degradation, as well as by recycling of soil organic matter carbon by soil microbes.