毛竹凋落物对阔叶林土壤微生物群落功能多样性的影响

Impacts of Litter of Phyllostachy pubescens on Functional Biodiversity of Soil Microorganism Communities in Broad-Leaved Forest

To investigate the effect of bamboo leaves on soil microorganism a microcosm experiment of soil mixture with different percentage of bamboo leaf powder was conducted.The biolog GN2 microtial plate was used to determine diversity indices of microorganism with the incubation time. The results showed that significant differences in microbial activities measured by average well color density（AWCD） were found among treatments,and treatments 2（with 2% of leaf powder） was lower AWCD than（P<0.05） the other treatments in the 10th week.Control（with 0% of leaf powder） was higher AWCD than（P<0.05） the treatments with bamboo leaf powder in the 20th and the 30th week.It was found that in short-term bamboo leaf had improved the soil microbial activity,and AWCD values of treatments 1（with 1% of leaf powder）,2 and 3（with 4% of leaf powder） respectively reached the maximum during 2 and 10 weeks,2 and 5 weeks,5 and 10 weeks,which ware all bigger（P<0.05） than that of non-cultured soil.However,a sharp decline was observed from the time of week 20 to week 30 at which the AWCD values of treatments 1,2 and 3 with 192（hour’s） incubation after microbes being inoculated were decreased by 64.8%,55.7% and 60.4% respectively compared with non-cultured soil.The control was found no remarkable changes before the 20th week,and then a sharp decline（by 40.4% compared to non-cultured soil） was measured from the 20th to the 30th week.No significant changes in Shannon index（H） and Evenes index（J’） in the control were found,whereas a sharp decline（P<0.05） was observed for treatments with bamboo leaf from the 20th to the 30th week.McIntosh index（U） sharply decline（P<0.05） for leaf treatments from the 10th to the 20th week and till the end of this experiment（week 30）,while a significant decline in McIntosh index of the control was found from the 20th to the 30th week.In summary the added amount of leaves did not led significant difference in soil microbial diversity indices analyzed.The diversity indices of control are significantly greater（P<0.05） than the leaf treatments at the 30th week,which indicated that single litter input of bamboo leaf for long-term caused a reduction of microbial functional diversity.