摘要
A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, China. Results showed that at 20℃ mass loss of leaf litter driven by microbial decomposers was higher in broadleaf forest than that in coniferous forest, whereas the difference in mass loss of leaf litter was not significant at 30℃. The temperature increase did not affect the mass loss of leaf litter for coniferous forest treatment, but significantly reduced the decomposition rate for broadleaf forest treatment. The functional decomposers of microorganism in broadleaf forest produced a higher lignin decomposition rate at 20℃, compared to that in coniferous forest, but the difference in lignin decomposition was not found between two forest types at 30℃. Improved temperature increased the lignin decomposition for both broadleaf and coniferous forest. Additionally, the functional group of microorganism from broadleaf forest showed marginally higher carbohydrate loss than that from coniferous forest at both temperatures. Temperature increase reduced the carbohydrate decomposition for broadleaf forest, while only a little reduce was found for coniferous forest. Remarkable differences occurred in responses between most enzymes （Phenoloxidase, peroxidase, !5-glucosidase and endocellulase） and decomposition rate of leaf litter to forest type and temperature, although there exist strong relationships between measured enzyme activities and decomposition rate in most cases. The reason is that more than one enzyme contribute to the mass loss of leaf litter and organic chemical components. In conclusion, at a community scale the coniferous and broadleaf forests differed in their temperature-decomposition relationships.
本研究分析了亚热带常绿阔叶林两个重要林型-针叶林与阔叶林在凋落物降解-温度关系的差异。研究表明,低温处理下阔叶林内微生物降解者所引起的凋落叶失重量高于针叶林,然而高温处理下两种林型内叶片失重量并未表现出显著差异。温度升高未引起针叶林内叶片失重量的变化,却显著降低了阔叶林内叶片失重量。低温处理下阔叶林内微生物功能群产生的木质素失重较针叶林高,但高温处理并未引起两林型内木质素失重的差异。温度升高提高两林型内木质素的降解。另外,两种温度处理下,阔叶林内微生物降解者功能群引起的碳水化合物降解高于针叶林。温度升高减少了阔叶林内碳水化合物降解,但并未改变针叶林内碳水化合物降解水平。尽管多数微生物降解酶活性与凋落物失重之间存在较强的相关性,但大多数酶对林型和温度的反应与叶片降解对林型和温度的反应不一致。原因在于叶片与其有机组分的降解是由多种降解酶共同作用的结果。总体上来说,针叶林与阔叶林表现出不同的温度-降解关系。
基金
This study was supported by National Natural Sci-ence Foundation of China (30470299)
Key Project of National Sci-ence Foundation of China (30430570).
