气温急变带工程创面植生层土壤及微生物群落特征研究

CHANGES OF SOIL PROPERTIES AND MICROBIAL COMMUNITY CHA RACTERISTICS IN THE PLANT-GROWTH MATRIX OF THE RESTORED ENGINEERING SLOPES UNDER DIFFERENT ELEVATIONS

青藏高原地处高寒缺氧的环境条件下,对人类扰动及气候变化非常敏感。人类活动如公路修建形成众多工程创面,对高原生态环境影响较大。创面生态修复的开展促进高原生态的恢复,但关于环境因子对生态修复过程中土壤及生物恢复的影响尚未探明。本研究选取青藏高原派墨公路中不同海拔的工程创面重构植生层,探究海拔变化下植生层土壤养分、酶活性及微生物群落的特征。研究结果表明:随着海拔变化,土壤氮磷养分含量总体随海拔升高先增加后减小,其中海拔3100 m左右的修复样地土壤养分整体优于其他海拔,其速效磷含量最高,同时全氮、氨态氮和全磷含量较高。此外,随着海拔的升高,土壤酸性蛋白酶和淀粉酶含量整体上略有升高的趋势。海拔变化对土壤酸性磷酸酶、纤维素酶、葡萄糖苷酶活性没有显著影响。海拔变化显著改变了土壤养分及土壤微生物的相对丰度(P<0.05),其中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)为优势种群,分别占土壤群落的35.81%~53.82%,8.49%~40.74%、5.98%~24.61%、3.17%~8.70%。微生物α和β多样性结果表明海拔显著影响土壤细菌群落多样性,不同海拔下的微生物群落组成在门水平上物种差异与标志物种不同。以上研究结果揭示了海拔梯度下创面生态修复重构土壤及微生物变化规律,对生态修复效果的科学评价具有重要意义。

The Qinghai-Tibet Plateau is located in cold region with high altitude and anoxic environmental conditions,which is very sensitive to human disturbance and climate change.Human activities,such as road construction,have formed numerous engineering slopes,which have a large impact on the ecosystem.The development of ecological restoration of engineering slopes promotes the recovery of ecosystems.But the influence of environmental factors on soil and biological recovery in the ecological restoration process has not been investigated.In this study,we investigate the characteristics of soil nutrients,enzyme activities and microbial communities in the plant-growth matrix under the altitude change on Pai-Mo Highway on the Qinghai-Tibet Plateau.The results of the study showed that the soil nitrogen and phosphorus nutrient contents increased and then decreased with the increasing elevation.The soil nutrients in the restoration sample site at an elevation of about 3100m were better than those in other elevations,and its available phosphorus content was the highest,while the contents of total nitrogen,available nitrogen and total phosphorus were also higher.In addition,the soil acid protease and amylase contents increased slightly with increasing altitude.Elevation did not significant effect soil acid phosphatase,cellulase,and sucrase activities.Besides,elevation changes significantly altered the relative abundance of soil nutrients and soil microorganisms(P<0.05),with Proteobacteria,Actinobacteria,Acidobacteria,and Chloroflexi being the dominant populations,accounting for 35.81%~53.82%,35.81%~53.82%,8.49%~40.74%,5.98%~24.61%,and 3.17%~8.70%of the soil community,respectively.The results of microbial alpha and beta diversity indicated that altitude significantly affected soil bacterial community diversity,and the microbial community composition differed from the markers in species with different altitudes.The results of the study reveal the change pattern of soil and microorganisms in the reconstructed soil of ecological restoration under the altitude gradient,which is important for the scientific evaluation of ecological restoration effect.