摘要
选取中亚热带米槠人促更新林(CCF)和杉木人工林(CLP)内的鲜叶、未分解层(L层)和半分解层(F层)凋落物为研究对象进行室内淋溶,对其淋溶液中的溶解性有机碳(DOC)、溶解性有机氮(DON)和溶解性有机磷(DOP)含量,紫外吸收值(SUVA),腐殖化指标(HIX)和红外光谱(FTIR)等进行了比较分析,以揭示其淋溶液中溶解性有机物(DOM)的数量和光谱学特征。结果表明:随着淋溶时间的增加,不同样品的DOM含量呈现先上升后下降,或者有波动的上升的趋势,这是因为DOM的释放和反吸附共同控制着DOM的含量。两林分中,F层凋落物DOM的SUVA值显著高于鲜叶和L层凋落物(P<0.05);从鲜叶到L层到F层凋落物,其HIX逐渐变大并且三者荧光强度最大值对应的波长由短波向长波移动,这是腐殖化程度越来越高、电子共轭体系逐渐增大的体现。两个林分6种样品的红外光谱显示了5个相似的吸收谱带,但不同样品各吸收带的相对比例不同,强度最大的吸收来自于H键键合的—OH的伸缩振动;同一林分内3种样品之间红外吸收的差异证明了鲜叶到L层再到F层凋落物,其DOM的芳香类物质含量逐渐升高,化学键力常数变小。总体上,与杉木人工林相比,米槠人促更新林的DOM养分含量更高,结构更复杂,因而更有利于有机质的积累。
DOM （Dissolved Organic Matter） is the most reactive pool of organic matter in ecosystems. Among others, it is the energy source of most microbial metabolism. It also plays a key role in the biogeochemistry of C/N/P due to its high mobility. In forest ecosystems, the amount of DOM that is respired, accumulated in soils or leached from the ecosystems are highly dependent on its chemical nature, which may differ between types and species of litter. Castanopsis carlesii forest （CCF） and Cunninghamia lanceolata plantation （CLP） are of dominant forest type and distributed widely in Fujian province, mid-subtropical China. While previous work focused on the biomass and carbon storage of the two kinds of stands,information on DOM from fresh leaves and litterfall from the two kinds of stands is rare. In this study, laboratory leaching experiments were carried out for leachates from fresh leaves and litterfall in L and F layers, which are from a 36-year-old Castanopsis carlesii forest （CCF） by artificially promoted regeneration and a 37-year-old Cunninghamia lanceolata plantation （CLP） in Sanming, Fujian province. We examined the quantities and spectral characteristics of DOM in terms of Dissolved Organic Carbon （DOC）, Dissolved Organic Nitrogen （DON） and Dissolvd Oganic Phosphorus （DOP） content, Special Ultraviolet-Visible Absorption （SUVA）, Humification Index （HIX） and Fourier Transform Infrared （FFIR） spectroscopy. The results showed that during leaching, the DOC, DON and DOP content in different samples either reached their maximum first followed by a decreasement, or showed an increasing valley and peak cycle; this is because that the release and desorption of DOM both controled the content of DOM. The amount of total DOC from CCF is comparable to that from CLP, but the amounts of DON and DOP are much higher than those from CLF. In the two stands, SUVA value of the DOM from F layer were significantly higher than those of fresh leaf and L layer （P〈0.05）, suggesting that
出处
《生态学报》
CAS
CSCD
北大核心
2014年第8期1946-1955,共10页
Acta Ecologica Sinica
基金
国家自然科学青年基金项目(31100467)
国家自然科学基金项目(31070548)
福建省自然科学青年基金项目(2011J05105)
福建师范大学优秀青年骨干教师培养基金项目(fjsdky2012008)
关键词
米槠
杉木
鲜叶
凋落物
溶解性有机物
光谱学特征
Castanopsis carlesii
Cunninghamia lanceolata
fresh leaf
litterfall
DOM
spectral characteristics
