水杉凋落物分解过程中溶解性有机质的分组组成变化

Dynamic changes of DOM fractions during the decaying process of Metasequoia glyptostrobodies litter

采用XAD-8树脂分组的方法研究水杉凋落物降解过程中DOM的含量及其组成的变化。结果表明,培养35天后DOC含量达到稳定值,而其组成仍未稳定。在整个培养过程中,HOA和HIM含量有明显变化;HON含量呈缓慢增加的趋势;AIM和HOB含量则没有明显变化。凋落物淋滤液DOM与表层土壤DOM组成相似,是土壤DOM的主要来源。土壤DOM中的AIM不是来源于凋落物淋滤液,而是主要来源于土壤腐殖质、根系分泌物等其它物质。

The composition and concentration of DOM extracted during the decaying process of Metasequoia glyptostrobodies litter were studied by the method of XAD-8 resin. The results showed that DOC increased gradually until constant after 35 daysincubation, but the compositions were still changing. The content of HOA and HIM changed as curve line in the whole incubation and HON increased slowly. But the content of AIM and HOB kept constant. The compositions of DOM released from litter were similar to that extracted from surface soil layer, which suggested litter was main source of DOM in the soil. AIM in the DOM of soil originated from microbial decay of humus or root exudates and so on.