Leaf litter decomposition of plants with different origin time in the mid\| subtropical China
不同起源时间的植物叶凋落物在中亚热带的分解特性

Leaf litter decomposition of 9 species with different origin time was studied from June 2006 to June 2008 in the Qiandaohu region of Zhejiang province using litterbag method, trying to explore the evolution trends of the leaf litter decomposition characteristics in the plant evolution process. The 9 species belong to 4 taxa, pteridophyta (Dicranopteris dichotoma and Alsophila spinulosa), gymnosperm (Cycas panzhihuaensis, Metasequoia glyptostroboides, Cunninghamia lanceolata and Pinus massoniana), dicotyledon (Schima superba and Cyclobalanopsis glauca), monocotyledon (Phyllostachys pubescens), which are ranked in the order of the origin time from earlier to later. The litterbags were collected every other month; there are three repeats for each species. The results indicated that the decomposition rate of litter of different taxa showed more correlation with the initial N contents, lignin contents and lignin/ N ratio of litter. The initial N contents of litter are increased with the origin time from earlier to later, the pattern is monocotyledon > dicotyledon > gymnosperm > pteridophyte. The patterns of the Lignin contents and Lignin/N ratio are similar. The values are decreased with the origin time from earlier to later, the pattern is pteridophyte > gymnosperm > dicotyledon > monocotyledon. The range of the annual litter decomposition coefficient (k) is 0.25 to 0.63, the trend is P. pubescens > C. glauca > S. superba > M. glyptostroboides > P. massoniana> C. lanceolata> C. panzhihuaensis > A. spinulosa > D. dichotoma. The mean litter decomposition rate of the 4 taxa is monocotyledon > dicotyledon > gymnosperm > pteridophyte. The results preliminary showed the evolution trends of the leaf litter decomposition rate are from slow gradually evolved to fast.