流沙区不同立地条件下防护林土壤微生物多样性分析

Diversity of Soil Microbe at Different Sites in Shelterbelt of Moving Sand Area

土壤微生物在极端干旱区土壤发育过程中至关重要。结合传统培养、PLFA和PCR-DGGE 3种方法,研究了塔里木沙漠公路防护林不同立地条件下土壤微生物数量、脂肪酸种类和DNA片段多样性。结果表明,不同立地条件下土壤微生物数量明显不同,脂肪酸种类和DNA片段多样性指数亦有显著差异(F<F0.05),表现为沙垄中部和基部大于沙垄顶部和板结平沙地,但均明显好于流沙地;土壤微生物区系中细菌为优势类群(>84%),放线菌次之,真菌很少(<0.05%);0～35cm采样范围内,土壤微生物多样性垂直差异不明显;相关分析表明,土壤微生物多样性指数高时林木生长也较好。说明塔里木沙漠公路防护林建设后土壤生物活性明显增强,但在防护林生态工程的营造、恢复与重建实践中需考虑地形地貌因素,以充分发挥防护林防风固沙效益,有效促进流沙地土壤的发育。

Soil microbe is crucial to soil development in extreme arid area.Methods of PLFA,PCR-DGGE,and cultivating and counting of microbe were used to investigate soil microbial quantity,fatty acid and microbial DNA segment at different sites in shelterbelt of Tarim Desert Highway because microbial isolation and culture techniques are able to culture less than 1% of the microbes present in soil.Results showed that the soil microbial amount,diversity indices of fatty acid and DNA segment differed notably among the different site conditions（FF0.05）,and they were bigger on middle parts and base parts of dunes than on top parts of dunes and harden flat sands,and all of them were better than on moving sands;Bacteria were dominant in soil microbial community（84%）,actinomycetes were second,and fungi were the least（0.05%）;Vertical difference of the soil microbial diversity was insignificant at 0~35 cm of soil.Correlation analysis indicated that the trees grew better as soil microbial diversity index enhanced.Therefore,the construction of shelterbelt along the Tarim Desert Highway promoted soil biological activities development,but we should consider effect of site condition on construction and regeneration of shelterbelt for enhancing sand control efficiency and promoting sandy soil development.