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以典型湖南省衡阳紫色土丘陵坡地不同植被恢复阶段为研究对象,采用空间代替时间序列的方法,选用立地条件基本相似的草本(狗尾草,GS)、灌草(紫薇-狗尾草,FG)、灌丛(牡荆+剌槐,FX)和乔灌(枫香+苦楝-牡荆,AF)群落阶段,运用Biolog-ECO微平板技术,对4个不同恢复阶段0~10和10~20 cm土层的土壤微生物功能多样性进行研究,探讨植被恢复对土壤微生物功能多样性的影响.结果表明:植被恢复后土壤微生物群落代谢活性显著升高,同一土层不同恢复阶段AWCD值的大小顺序为乔灌群落>灌丛群落>灌草群落>草本群落,相同恢复阶段不同土层的AWCD值的大小顺序为0~10 cm>10~20 cm;主成分分析(PCA)表明,灌草群落与灌丛群落具有相似的土壤微生物C源利用方式及代谢功能,而草本群落、乔灌群落具有不同的C源利用方式及代谢功能,在主成分分离中起主要贡献作用的C源是糖类、氨基酸类以及代谢中间产物和次生代谢物;土壤微生物的Shannon物种丰富度指数(H)、Shannon均匀度指数(E)、Simpson优势度指数(D)和Mc Intosh指数(U)均以乔灌群落最高,灌草群落和灌丛群落次之,草本群落最低;相关分析表明,土壤含水量(SWC)、土壤总有机碳(STOC)、全氮(TN)、全磷(TP)和速效磷(AP)对土壤微生物代谢功能及功能多样性指数有重要影响,脲酶(URE)、磷酸酶(APE)、蔗糖酶(INV)和过氧化氢酶(CAT)活性与土壤微生物代谢功能及功能多样性指数存在显著相关关系.表明植被恢复可使土壤微生物代谢功能增强,土壤微生物繁殖加快、数量增大,从而促进土壤微生物对土壤C源的利用强度.
Taking the typical vegetation restoration stage of the purple hills in Hengyang, Hunan Province as the research object, the spatial substitution of time series was used to select the grass with similar site conditions (Setaria viridis, GS), shrub (Crape myrtle - foxtail grass, FG) (Vitis vinifera + Acacia, FX) and Qiao irrigation (Liquidambar formosana + Melia azedarach, AF), using Biolog-ECO microplate technique, The results showed that the metabolic activity of soil microbial community increased significantly after the restoration of vegetation, and the order of AWCD value in different recovery stages of the same soil was in the order of tree and shrub Shrub community> shrub-grass community> herb community. The order of AWCD values of different soil layers in the same restoration stage was 0 ~ 10 cm> 10 ~ 20 cm. The principal component analysis (PCA) The communities had similar C-source utilization patterns and metabolic functions of soil microorganisms. However, the herbaceous communities and tree-shrub communities had different utilization patterns of C sources and metabolic functions. The C sources that played a major role in the main component separation were sugars and amino acids And generation Intermediate and secondary metabolites. Shannon’s species richness index (H), Shannon evenness index (E), Simpson dominance index (D) and Mc Intosh index (U) The grass community and shrub community were the second, and the herb community was the lowest. The correlation analysis showed that SWC, STOC, TN, TP and AP Soil microbial metabolism and functional diversity index had significant effects. URE, APE, INV and CAT activities were significantly correlated with metabolic and functional diversity index of soil microorganisms The results show that vegetation restoration can enhance the metabolic function of soil microorganisms, accelerate the multiplication of soil microorganisms and increase the quantity of soil microorganisms, so as to promote the intensity of soil C source utilization by soil microorganisms.