【作者】 杨洁；

【导师】 段昌群；

【作者基本信息】 云南大学 ， 生态学， 2023， 硕士

【摘要】 采矿活动为人类社会提供大量物质基础的同时也对生态系统造成了巨大损害。形成的大量矿区废弃地亟待治理修复。植物修复作为一种绿色且低成本的矿区修复方式受到科研人员的广泛关注。野外调查发现,一种适生于铅锌矿区废弃地的本土植物——马桑(Coriarianepalensis)对污染和极端生境的适应性以及对周围微环境的改良作用,以其形成植物群落可能有助于矿区废弃地自然恢复。为此,本研究以自然定植在会泽县矿山镇铅锌矿区废弃地中的保育植物马桑为研究对象,采用野外植物样方调查取样和土壤理化性质测定等方法,探究不同废弃年限下以马桑为建群种的群丛生态特征及马桑对土壤理化性质、土壤重金属赋存特征和土壤微生物群落的影响,全面综合分析马桑在不同年限铅锌矿区废弃地中的环境改良效能及机制。具体研究结果如下:1.在铅锌矿区废弃地中,马桑对植物具有良好的保育作用,可帮助其他植物物种在其冠下定植。在斑块及样地尺度上,均增加了物种丰富度。各样地马桑群丛样方生物量均显著高于草本样方。而随着废弃年限的不断增加,马桑群丛中优势物种的组成从废弃前期以禾本科、豆科为主转变为以禾本科、豆科、菊科及玄参科为主,再到后期以菊科为主。同时,随着废弃年限的不断增加,马桑群丛中出现灌木幼苗及乔木幼苗的物种数不断增加。2.马桑可改变原生栖息地,减少非生物胁迫对冠下植物的危害。与草本样点相比,不仅马桑冠幅内土壤性状有所改善,马桑冠幅外的土壤性状也有所改良。表明马桑群丛促进冠下土壤结构趋于稳定,土壤局部资源增加并出现“肥岛”效应。其土壤改良效应体现在以下三方面:(1)改善物理特性:相较于草本样点,马桑群丛土壤容重显著低于草本样点;土壤含水率显著高于草本样点。(2)提升土壤营养:大多样地马桑根际土的有机质、全氮、全磷、铵态氮、有效磷含量均显著高于草本样点。(3)减轻土壤重金属对植物的毒性:虽然马桑群丛重金属总量及有效态均显著高于草本样方,但马桑群丛下植物多样性及生物量并未受到影响,反而更高,这表明马桑减缓了重金属对其冠下植物的胁迫及毒害,使得植物能够在冠下定植生长。3.基于马桑根际及草本样点微生物组成研究发现,各样点微生物组成相似,但每个菌门丰度存在差异。对于细菌而言,马桑根际细菌群落的变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)的丰度均高于草本样点,而草本样点的绿弯菌门(Chloroflexi)的丰度则高于马桑根际。马桑根际真菌群落的子囊菌门(Ascomycota)、担子菌门(Basidiomycota)的丰度均高于草本样点,而草本样点的球囊菌门(Glomeromycota)、壶菌门(Chytridiomycota)的丰度则高于马桑根际。4.基于FAPROTAX的细菌功能预测发现,马桑根际与固氮作用、硝酸盐还原、氮呼吸、硝酸盐呼吸相关的细菌功能丰度更高。基于Bugbase的细菌功能预测发现,在大多样地,马桑根际存在更多的压力耐受、兼性厌氧菌、形成生物膜、好氧菌、包含移动原件及革兰氏阴性菌。而基于FUNGuild的真菌功能预测发现,马桑根际腐生营养型相关的功能丰度更高,进一步细分功能群发现木质腐生真菌相关的功能丰度更高。综上所述,马桑在铅锌矿区废弃地可通过改善微生境土壤特性及调节土壤微生物群落结构对其冠下植物产生保育作用,从而使退化环境植物群落演替。通过全面综合分析马桑在铅锌矿区废弃地中的环境改良效能及机制,旨在为铅锌矿区废弃地植被重建及修复提供理论依据。更多还原

【Abstract】 Mining activities provide a large material base for human society,they also cause significant damage to ecosystems.The large amount of mine waste land formed is in urgent need of treatment and restoration.Phytoremediation has received a lot of attention from researchers as a green and low-cost way to remediate mine sites.Field survey revealed that a native plant,Coriaria nepalensis,adapted to the abandoned sites of Pb-Zn mines for its adaptability to pollution and extreme habitats and its improvement of the surrounding microenvironment,with its formation of plant communities may contribute to the natural recovery of the abandoned sites of mines.For this reason,the present study was conducted on the nurse plant,C.nepalensis,which was naturally colonized in the abandoned land of the Pb-Zn mine in Mine Town,Huize County.Using methods such as field plant sample survey sampling and soil physical and chemical property determination,to investigate the ecological characteristics of association C.nepalensis as a constructive species and the effects of C.nepalensis on soil physicochemical properties,soil heavy metal existence speciation and soil microbial community under different years of abandonment.A comprehensive and integrated analysis of the environmental improvement efficacy and mechanisms of C.nepalensis in abandoned sites of Pb-Zn mines of different ages.The specific results of the study are as follows:1.In abandoned sites of Pb-Zn mines,C.nepalensis has a good nurse effect on plants and can help other plant species to colonize under its canopy.Species richness was increased at both the patch and sample site scales.The biomass was significantly higher in all sample sites in the C.nepalensis association samples than in the herbaceous samples.As the number of years of abandonment increased,the composition of dominant species in the C.nepalensis association changed from predominantly Gramineae and Leguminosae to predominantly Gramineae,Leguminosae,Asteraceae and Geniculaceae in the early stages of abandonment,and then to predominantly Asteraceae in the later stages.At the same time,the number of species with shrub seedlings and tree seedlings appearing in the C.nepalensis association is increasing with the increasing number of years of abandonment.2.C.nepalensis can alter native habitats and reduce abiotic stresses on subcanopy plants.Compared with the herbaceous sample sites,not only the soil properties within the C.nepalensis canopy were improved,but also the soil properties outside the C.nepalensis canopy were improved.It shows that the C.nepalensis association promotes the stabilization of the soil structure under the canopy,and the local resources of the soil increase and the"fertilizer island" effect appears.Its soil improvement effect is reflected in the following three aspects:(1)Improvement of physical properties:Compared with the herbaceous sample sites,the soil bulk density of the C.nepalensis association was significantly lower than that of the herbaceous sample sites;the soil moisture content was significantly higher than that of the herbaceous sample sites.(2)Enhancement of soil nutrients:organic matter,total nitrogen,total phosphorus,ammonium nitrogen,and effective phosphorus contents of the inter-rhizosphere soil in a large variety of C.nepalensis sites were significantly higher than those of the herbaceous sample sites.(3)Reducing the toxicity of soil heavy metals to plants:Although the total amount and effective state of heavy metals in the C.nepalensis association were significantly higher than those in the herbaceous samples,the plant diversity and biomass under the C.nepalensis association were not affected but higher,indicating that the C.nepalensis reduced the stress and toxicity of heavy metals to the plants under its canopy,allowing the plants to colonize and grow under the canopy.3.Based on the microbial composition of C.nepalensis inter-rhizosphere and herbaceous sample sites,it was found that the microbial composition of each site was similar,but there were differences in the abundance of each phylum.For bacteria,the abundance of Proteobacteria and Bacteroidetes in the C.nepalensis inter-rhizosphere bacterial community was higher than that in the herbaceous sample sites,while the abundance of Chloroflexi in the herbaceous sample sites was higher than that in the C.nepalensis inter-rhizosphere.The abundance of Ascomycota and Basidiomycota in the C.nepalensis inter-rhizosphere fungal community was higher than that in the herbaceous sample sites,while the abundance of Glomeromycota and Chytridiomycota in the herbaceous sample sites was higher than that in the C.nepalensis inter-rhizosphere.4.The prediction of bacterial functions based on FAPROTAX revealed higher abundance of bacterial functions related to nitrogen fixation,nitrate reduction,nitrogen respiration,and nitrate respiration in the C.nepalensis inter-rhizosphere.Bugbase based prediction of bacterial function revealed the presence of more stress tolerant,parthenogenic anaerobic bacteria,biofilm forming,aerobic bacteria,mobile progenitor containing and Gram-negative bacteria at large diverse sites in the C.nepalensis inter-rhizosphere.while FUNGuild-based fungal function prediction revealed higher abundance of functions associated with C.nepalensis inter-rhizosphere.saprophytic trophic type,and further subdivision of functional groups revealed higher abundance of functions associated with woody saprophytic fungi.To sum up,C.nepalensis in Pb-Zn mine abandoned sites can nurse under-canopy plants by improving microhabitat soil properties and regulating soil microbial community structure,thus enabling plant community succession in degraded environments.Through a comprehensive analysis of the environmental improvement efficacy and mechanism of C.nepalensis in abandoned sites of Pb-Zn mines,we aim to provide a theoretical basis for the revegetation and restoration of abandoned sites of Pb-Zn mines.更多还原