杉木宿存叶片的分解及稳定性碳氮同位素和化学组成  

Decomposition,carbon and nitrogen stable isotopes and chemical composition of dead leaves clinging in a Chinese fir( Cunninghamia lanceolata) plantation

作　　者：郜士垒 何宗明[1,2] 黄志群[3] 林思祖[1,2] 刘桌明 

机构地区：[1]国家林业局杉木工程技术研究中心,福州350002 [2]福建农林大学林学院,福州350002 [3]福建师范大学地理科学学院,福州350007

出　　处：《生态学杂志》2015年第9期2457-2463,共7页Chinese Journal of Ecology

基　　金：2011年教育部新世纪优秀人才支持计划项目(DB-168);福建农林大学部级创新平台项目资助

摘　　要：杉木枯死枝叶由于长期宿存于树冠,不易脱落,且生物量大,其分解和养分释放对杉木人工林营养循环具有重要意义。用比叶质量法估算了我国亚热带地区福建南平17年生杉木树冠层不同高度宿存叶片的分解程度,测定了碳氮含量、碳氮稳定性同位素及有机碳化学组成。结果表明：杉木宿存叶片的比叶质量呈现出由上向下逐渐减小的趋势,树冠8~10 m处宿存叶片的比叶质量（26.02 mg·cm-2）显著大于刚死杉木叶片的比叶质量（23.12 mg·cm-2）和6~8 m处宿存叶片的比叶质量（15.39 mg·cm-2）,而0~2、2~4和4~6 m这3层宿存叶片的比叶质量无显著差异。刚死杉木叶的碳含量（50.67%）和氮含量（0.75%）显著低于不同高度宿存叶片的碳氮含量,而不同高度宿存叶片的碳氮含量和碳氮比均无显著差异。刚死杉木叶片的碳氮比（67.58）显著高于不同高度宿存叶片的碳氮比。当杉木宿存叶片的C/N为45.91±0.45时开始净氮释放。刚死杉木叶片和8~10 m高度处宿存叶片δ15N值显著高于其他高度宿存叶片,而其他高度宿存叶片的δ15N含量无显著差异。不同高度杉木宿存叶片的δ13C无显著差异。杉木宿存叶片中多糖碳和乙缩醛碳首先被分解,而烷基碳、芳碳、酚碳和羧基碳的分解速度比多糖碳和乙缩醛碳的慢。The decomposition and nutrition release of the dead canopy leaves and branches are critical for the nutrient cycling in Chinese fir（ Cunninghamia lanceolata） because they can cling to stems for several years and are of large biomass. In this paper,we estimated the decomposition degree of these dead leaves in the canopy of different heights in a 17-year-old C. lanceolata plantation by determining the leaf mass per area. We also measured carbon（ C） / nitrogen（ N） ratio,C and N isotope compositions and chemical compositions of the dead leaves. The results showed that the leaf mass per area of the dead leaves at the lower canopy was lower. The leaf mass per area of the dead leaves in 8- 10 m（ 26.02 mg·cm-2） was much higher than the leaves that just died（ 23.12 mg·cm-2） and the leaves in 6-8 m（ 15.39 mg·cm-2）. However,there was no significant difference in the leaf mass per area of dead leaves at 0-2,2-4,or 4-6 m. C and N concentrations in the recently dead leaves were significantly lower than in the dead leaves clinging to branches of different heights. No significant differences in C and N concentrations and in C / N ratio were found between the dead leaves clinging at different heights of canopy. The C / N ratio（ 67.58） in the recently dead leaves was significantly higher than that in the dead leaves clinging to the branches of different heights. When the C / N ratio in the dead leaves clinging to the branches reached 45.91±0.45,the nitrogen started to release. The values of δ15N of the recently dead leaves and the dead leaves clinging at canopy of 8- 10 m height were greater than in that of the dead leaves clinging at canopy of other heights. However,no difference was found for the dead leaves clinging at the canopy of 0-2,2-4,4-6,and 6-8 m. The values of δ13C in dead leaves clinging at the canopy of different heights were not significantly different. Moreover,we demonstrated that polysaccharide C and aldehyde acetal C in the dead leaves clinging at the canopy decomposed firstly a

关 键 词：碳结构 核磁共振 δ15N δ13C 

分 类 号：S791.27[农业科学—林木遗传育种]