川西高海拔增温和加氮对红杉凋落物有机组分释放的影响

发布时间：2019-03-03 09:36

【摘要】：对川西高山树线红杉新鲜凋落物中有机组分于11月进行自然条件(对照)、加氮(2g N·m~(-2))、增温(顶开式培养室)、加氮+增温4个处理的原位培养,并监测凋落物中有机组分的分解动态.结果表明:在试验开始后4个月内,增温、加氮以及加氮+增温处理比对照显著促进了红杉凋落物中水溶性糖、水溶性酚和多酚的分解,但随着培养时间的延长,累积分解量的差异逐渐缩小.与对照相比,增温、加氮和增温+加氮处理均抑制红杉凋落物中CH_2Cl_2提取组分、酸溶碳水化合物、酸溶木质素和非酸溶木质素分解,其中增温处理抑制作用最强,加氮处理抑制效果最弱,增温+加氮处理介于二者之间;增温处理对非酸溶木质素和CH_2Cl_2提取组分的半分解周期延长1倍以上,热水溶组分的半分解周期延长50%以上.在原位培养条件下,红杉新鲜凋落物中水溶性糖、水溶性酚、多酚、酸溶碳水化合物、酸溶木质素是较容易分解的有机组分,半分解周期分别为182、159、127、154和190 d;热水溶组分、CH_2Cl_2提取组分和非酸溶木质素是较难分解的有机组分,半分解周期分别是209、302和318 d;尽管低温季节(11月至次年3月)极其寒冷,气温均低于0℃,常被认为是微生物活性最弱、有机物分解最慢的时期,但结果显示低温季节期间红杉凋落物各有机组分却分解最快.因此,氮沉降和升温将迟滞该区域高寒红杉林凋落物的分解.这将有利于高寒森林生态系统的土壤碳固持.
[Abstract]:In November, natural conditions (control), nitrogen (2g N 路m ~ (- 2),) and nitrogen warming (in situ culture) were applied to the fresh litter of yew in the alpine tree line of western Sichuan, and the results were as follows: (1) the fresh litters were cultured in situ under the condition of natural condition (control), nitrogen (2g N 路m ~ (- 2) and nitrogen. And monitor the decomposition dynamics of components in litter. The results showed that the decomposition of water-soluble sugar, water-soluble phenol and polyphenol in litters of Taxodium lanceolata was significantly promoted by heating, nitrogen and nitrogen treatments within 4 months after the beginning of the experiment, but with the prolongation of culture time, the decomposition of water-soluble sugar, water-soluble phenol and polyphenol in litters was significantly increased. The difference in cumulative decomposition amount was gradually reduced. Compared with the control, the CH_2Cl_2 extraction components, acid-soluble carbon-water compounds, acid-soluble lignin and non-acid-soluble lignin decomposition were inhibited by the treatments of warming, nitrogen and nitrogen, among which, the temperature-increasing treatment had the strongest inhibitory effect on the decomposition of the acid-soluble carbon-water compound, the acid-soluble lignin and the non-acid-soluble lignin. The inhibition effect of nitrogen addition treatment was the weakest, and the temperature increase and nitrogen addition treatment was in the middle of the two treatments. The semi-decomposition period of non-acid-soluble lignin and CH_2Cl_2 extracts was prolonged by more than one-fold and the half-decomposition period of hot-water soluble components was prolonged by more than 50%. Under the condition of in-situ culture, water-soluble sugar, water-soluble phenol, polyphenol, acid-soluble carbon-water compound and acid-soluble lignin were easy to decompose in the fresh litters of Taxus lanceolata. The semi-decomposition periods were 182159127154 and 190 d, respectively. Hot water soluble components, CH_2Cl_2 extraction components and non-acid soluble lignin are difficult to decompose organic components, and the semi-decomposition periods are 209302 days and 318d, respectively. Although the low temperature season (November to March of the following year) is extremely cold and temperatures are below 0 鈩，

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