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毛竹原状和粉状叶片分解特征对施氮和温度的响应

Response of Decomposition Feature of the Original and Powdered Moso Bamboo (Phyllostachys edulis) Leaves to Nitrogen and Temperature

  • 摘要: 目的 毛竹(Phyllostachys edulis)叶片分解与竹林碳循环和养分周转关系密切,通过室内模拟氮沉降和温度升高试验,为预测未来气候变暖和氮沉降条件对凋落竹叶分解的调控提供参考,为科学管理毛竹林提供科学依据。方法 以毛竹原状叶片及粉状叶片(粉碎过2 mm)为研究对象,布设3因素2水平试验,即施氮(添加氮5 mg ·g-1)和不加氮对照,12℃和28℃培养温度,原状和粉状叶片,恒温箱中培养78 d,采用密闭碱液吸收法定期测定CO2释放量,并计算分解速率。结果 表明:施氮处理、培养温度和叶片形态及其交互作用对凋落竹叶分解速率的影响因培养阶段不同而存在差异,总体上表现为培养前期(0-23 d)和培养中期(24-48 d)的分解速率高于培养后期(49-78 d)。从均值来看,施氮处理抑制原状叶片在12℃培养下的分解速率,而对两种形态叶片在28℃培养条件的分解速率影响不显著;施氮处理可增加原状凋落竹叶分解速率的温度敏感性(Q10),但对粉状凋落竹叶分解速率的Q10值影响不显著,且原状凋落竹叶分解速率的Q10值高于粉状凋落叶。凋落竹叶C/N在培养后期显著升高,且氮添加显著促进粉状竹叶C/N增加。结论 氮沉降对毛竹凋落叶分解的影响效应与培养温度和叶片形态有关。凋落物分解的影响因素众多,凋落物分解对全球环境变化的响应不仅应该深入研究其化学和生物学机制,还要关注物理过程及其调控潜能。

     

    Abstract: Objective Decomposition of Moso bamboo (Phyllostachys edulis (Carr.) H.de Lehaie) leaves and carbon and nutrient cycling of Moso bamboo forest are closely related. The research on atmospheric nitrogen deposition and global warming environmental changes on Moso bamboo leaves decomposition aims at providing a theoretical basis for the current countermeasures of bamboo forest management. Method The original leaves and powdery leaves of Moso bamboo (through the 2 mm sieve) was tested at three factors and two levels of completely randomized trial, i.e. added nitrogen (5 mg·g-1) and controls without nitrogen, cultivated temperature at 12℃ and 28℃, original leaves and powdery leaves, cultured in incubator for 78 days, the CO2 emissions were measured periodically by the sealed alkali absorption method, and the rate of decomposition were calculated. Result The effects of nitrogen fertilizer treatment, temperature and leaf shape and their interactions on the decomposition rate of Moso bamboo litter leaves were different at different periods. On the whole, the decomposition rate of Moso bamboo litter leaves were faster in pre-cultured (0-23 d) and mid-cultured (24-48 d) than that in post-cultured (49-78 d). The added nitrogen treatment inhibited the decomposition rate of original leaves at 12℃ in mean, while it had no significant effects on those of the two morphological leaves at 28℃. The temperature sensitivity (Q10) of original leaves decomposition rate increased by the treatment of added nitrogen, but the effect of added nitrogen on the Q10 of powdered litter leaves was not significant. Meanwhile, the Q10 of original bamboo litter decomposition rate was higher than that of powdery litter leaves. In addition, the C/N of bamboo leaf litter increased significantly after culture, and the increase in the powdery bamboo leaves with the nitrogen addition was more dominant. Conclusion The effects of nitrogen deposition on litter decomposition of Moso bamboo are related to cultivation temperature and leaf morphology. In summary, the impact of litter decomposition is numerous, so the study on the response of litter decomposition to global climate change should not only focus on its chemical and biological mechanism, but also on the physical process and its regulatory potentials.

     

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