降解剂对森林凋落物可溶性有机碳含量的影响及凋落物降解模式比较研究

森林凋落物是森林生态系统中可溶性有机碳(DOC)的主要来源，在生态系统碳循环过程中起重要作用。以帽儿山地区胡桃楸、兴安落叶松以及胡桃楸-兴安落叶松人工林凋落物为研究对象，通过液体发酵培养将纤维素高效降解真菌Peniophora intranata与Sarocladium strictum制成单一(A菌剂、B菌剂)及混合菌剂(C菌剂),测定野外条件下经降解剂处理的凋落物基质在不同时期的DOC含量，分析降解剂对不同类型森林凋落物DOC动态变化的影响，并比较各凋落物基质降解模式异同。结果表明：(1)凋落物基质DOC含量在降解剂处理后均随降解时间增加呈下降趋势，且下降幅度大小表现为混合基质>胡桃楸基质>落叶松基质；在最初的1个月，各凋落物基质DOC含量均显著高于其他降解时期DOC含量。(2)经混合菌剂处理后的胡桃楸基质DOC含量相较于2种单一菌剂处理后的胡桃楸基质DOC含量低，而经混合菌剂处理后的兴安落叶松基质与胡桃楸-兴安落叶松基质的DOC含量未表现出相同的显著性。(3)经3种菌剂处理后的胡桃楸基质降解模式均相同，经B菌剂与C菌剂处理的落叶松基质降解模式相同，经A菌剂与C菌剂处理...

Effects of degrading agents on dissolved organic carbon content of forest litter and comparative study on litter degradation modes

Forest litter is the main source of dissolved organic carbon (DOC) in forest ecosystem and plays an important role in the process of ecosystem carbon cycle. In this study, the litter of Juglans mandshurica, Larix gmelinii and their mixed plantation in Maoer Mountain were taken as research objects. The high-efficiency cellulose degrading fungi Peniophora intranata and Sarocladium strictum were made into single (agent A, agent B) and mixed fungal agent (agent C) by liquid fermentation culture. The DOC content of forest litters treated with agents in different periods under field conditions was measured. The effects of degrading agents on the dynamic changes of DOC content of different types of litters were analyzed, and the similarities and differences of degradation modes of each litter substrate were compared. Results showed that DOC contents of the three litter substrates showed a downward trend with the increase of degradation time after treatment, and the decreasing range was in the order of mixture > J. mandshurica > L. gmelinii. In the first month, the DOC content of each litter substrate was significantly higher than that of other degradation periods. The DOC content of J. mandshurica substrate treated with the mixed fungal agent was lower than that treated with the two single fungal agents, but the DOC content of L. gmelinii and mixed substrate treated with mixed fungal agent did not show the same significance. The degradation modes of J. mandshurica substrate treated with the three kinds of agent were same. The degradation mode of L. gmelinii substrate treated with agent B was the same as that treated with agent C, and the mode of mixed substrate treated with agent A was the same as that treated with agent C. This study shows that the types of litter affect the release capacity of DOC. The mixed fugal agent made of two strains with synergistic effect has stronger ability to degrade litters than that made of single strain, so as to promote the release of DOC. At the same time, it is also affected by the composition of litter substrates. This study provides a scientific basis for forest litter decomposition and carbon management in Maoer Mountain area by comparing the dynamic changes of DOC and degradation modes of different types of litter under the treatment of degrading agents.