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1.
紫茎泽兰入侵对土壤细菌的群落组成和多样性的影响   总被引:1,自引:0,他引:1  
外来生物入侵可能对生物群落结构和生态系统功能产生多种影响, 但入侵植物与土壤微生物群落组成和多样性的关系尚不清楚。为了揭示外来植物紫茎泽兰(Eupatorium adenophorum)入侵对土壤化学性质和细菌群落组成及多样性的影响, 本研究利用第二代高通量测序技术, 比较了紫茎泽兰不同入侵程度的生境(本地植物群落、紫茎泽兰与本地植物混生群落、紫茎泽兰单优群落)土壤中细菌群落的差异。土壤化学性质分析表明, 土壤pH值、有机质、全N和全K随着紫茎泽兰的入侵而逐渐降低, 而土壤全P则在入侵程度最高的生境土壤中最高。通过测序共获得7,755个细菌OUT (operational taxonomic unit)。结果表明, 紫茎泽兰入侵对土壤的细菌多样性影响较小, ACE和Chao指数在3种不同生境间的差异不显著。细菌在紫茎泽兰与本地植物混生群落中的Shannon指数最低, 即细菌的多样性在中等入侵程度的生境最低。此外, 紫茎泽兰入侵改变了土壤细菌组成和结构, 酸杆菌门(Acidobacteria)和疣微菌门(Verrucomicrobia)的相对丰度, 从本地植物群落、混合群落到紫茎泽兰单优群落, 呈现出先增加后减少的趋势。可见, 紫茎泽兰入侵一定程度上改变了土壤微生物的多样性和群落结构, 并改变了土壤的化学性质。  相似文献   

2.
入侵植物紫茎泽兰根围土壤化学及微生物属性海拔变化格局 热带地区山地生态系统是外来植物入侵的重要区域,是研究外来植物扩散机制的“天然实验室”。本研究试图探明入侵植物紫茎泽兰(Ageratina adenophora)根围土壤化学(pH及土壤养分)和微生物(酶活性和细菌群落)特性沿海拔梯度的变化规律。本研究以哀牢山(1400–2400 m)不同海拔梯度分布的紫茎泽兰为研究对象,采集根围土,测定土壤有机碳及养分含量,以及植物根系碳和氮含量。分析与土壤有机碳、氮及磷循环的酶活性,通过计算土壤酶化学计量参数,探究微生物生长代谢利用碳、氮及磷的规律。借助高通量测序技术对16S rDNA的V4区测序,分析细菌群落结构。研究结果显示,海拔显著影响紫茎泽兰根系氮及及其根围土壤有机碳含量,且这些测量指标在海拔2000 m  出现拐点。处在低海拔,入侵植物快速生长耗竭土壤中相对缺乏的磷,磷素是限制微生物生长的重要养分元素;而在高海拔,微生物需要投入更多的能量降解有机质获取碳,导致微生物生长的碳限制。细菌群落β多样性及pH  是决定不同海拔酶化学计量参数差异的重要因子;变形菌门和酸杆菌门是决定微生物养分利用状况的主要细菌门类。这些结果阐明了不同海拔梯度上紫茎泽兰根围土壤微生物的养分利用规律,有助于认识入侵植物沿海拔扩散机制。  相似文献   

3.
为了揭示外来植物紫茎泽兰入侵对入侵地土壤丛枝菌根真菌(AMF)群落及相关肥力的影响,比较测定了紫茎泽兰不同入侵程度土壤理化性质、AMF侵染率及AMF群落的差异。结果表明,紫茎泽兰入侵降低了土壤pH,使土壤中有机碳、全氮和速效钾含量分别增加83.0%,106.9%和111.0%;尽管对全磷含量没有显著影响,但有机磷含量呈升高的趋势,而速效磷呈降低的趋势。紫茎泽兰入侵降低了本地植物的AMF侵染率;随着入侵程度的加深,土壤中以膨胀无梗囊霉(Acauospora dilatata)为优势种的AMF群落结构逐渐转变为以近明球囊霉(Glomus claroideum )为优势种的结构,紫茎泽兰可在其根周选择培育近明球囊霉,而对其它AMF种,特别是对膨胀无梗囊霉则存在抑制作用;基于各AMF种多度的聚类分析表明,形成紫茎泽兰单优群落土壤中各AMF种多度与未入侵的本地植物群落及入侵程度较轻的紫茎泽兰与本地植物群落之间存在明显分歧。综合分析推断认为,紫茎法兰入侵改变了入侵地土壤理化性状,抑制AMF对土著植物的侵染,改变AMF群落,并在其根周选择培育近明球囊霉,这可能是紫茎泽兰入侵及扩张的重要途径之一。  相似文献   

4.
紫茎泽兰入侵对土壤酶活性和理化因子的影响   总被引:8,自引:0,他引:8  
刘潮  冯玉龙  田耀华 《植物研究》2007,27(6):729-735
紫茎泽兰是我国危害最严重的外来入侵植物之一,为探明其入侵对土壤肥力的影响,比较研究了紫茎泽兰、云南菅、狗尾草群落和撂荒地下0~30 cm的4层土壤中6种酶活性和12种理化因子。结果表明群落类型和土壤深度对测定的各参数均有显著影响。随土壤深度的增加,多酚氧化酶、碱性磷酸酶、脲酶活性,以及有机质、全氮、全磷、全钙、水解氮、有效磷、速效钾含量和pH值均降低。总的看来,紫茎泽兰群落下碱性磷酸酶和脲酶活性,有机质、全氮、全磷、全钙、水解氮和有效磷含量,以及pH值均较高,全钾含量较低,但速效钾含量并不低,表明紫茎泽兰入侵多年后土壤肥力水平提高,形成了对其生长有利的土壤环境。  相似文献   

5.
黄顶菊入侵对土壤氨氧化细菌群落结构及多样性的影响   总被引:1,自引:0,他引:1  
入侵植物通常会改变入侵地土壤微生物群落,进而影响到土壤养分循环以及物种之间的竞争格局。研究入侵植物对入侵地土壤微生物群落的影响不仅可以评估其对入侵地生态系统的影响,也为探明外来植物入侵的土壤微生物学机制提供理论依据。本文利用聚合酶链式反应变性梯度凝胶电泳(PCR-DGGE)技术及序列分析方法研究了入侵植物黄顶菊对入侵地土壤氨氧化细菌(AOB)多样性和系统发育的影响。结果表明:未入侵土壤(CK)、入侵地根围土(BS)和入侵地根际土(RPS)土壤AOB主要为亚硝化螺菌属(Nitrosospira sp.)、亚硝化弧菌属(Nitrosovibrio)、不可培养的亚硝化单胞菌属(Nitrosomonas)和不可培养的氨氧化细菌。其中,亚硝化螺菌群和不可培养的氨氧化细菌为各样地的优势类群。各样地AOB的Shannon指数(H)变化趋势为:RPSCKBS,土壤硝化潜势变化趋势与之一致,而影响H的关键理化因子分别是土壤硝态氮和铵态氮含量。黄顶菊入侵降低了BS的AOB活性,并表现出明显的根际效应,暗示黄顶菊可能通过加速自身根际氮素周转实现其成功入侵。  相似文献   

6.
外来入侵植物不仅影响植物群落组成、生物多样性以及生态系统的结构和功能, 而且显著影响土壤氮(N)的转化过程。外来入侵植物对N循环影响的研究已成为入侵生态学的研究热点。N循环与凋落物的分解和养分释放有关, 外来入侵植物能够改变凋落物的组成与结构, 进而影响土壤的N转化过程。另外, 外来入侵植物的化感作用也会影响土壤N转化过程, 这些作用与土壤微生物的结构与功能变化密不可分。该文主要从凋落物分解与养分释放及外来入侵植物化感作用两个方面综述了外来入侵植物对土壤N转化的影响, 总结了外来入侵植物对土壤N转化相关土壤微生物(尤其是氨氧化细菌与氨氧化古菌)的影响, 探讨了土壤N转化对外来植物入侵的反馈, 并探讨了丛植菌根真菌与外来入侵植物的互相影响。  相似文献   

7.
《植物生态学报》2018,42(11):1071
外来入侵植物不仅影响植物群落组成、生物多样性以及生态系统的结构和功能, 而且显著影响土壤氮(N)的转化过程。外来入侵植物对N循环影响的研究已成为入侵生态学的研究热点。N循环与凋落物的分解和养分释放有关, 外来入侵植物能够改变凋落物的组成与结构, 进而影响土壤的N转化过程。另外, 外来入侵植物的化感作用也会影响土壤N转化过程, 这些作用与土壤微生物的结构与功能变化密不可分。该文主要从凋落物分解与养分释放及外来入侵植物化感作用两个方面综述了外来入侵植物对土壤N转化的影响, 总结了外来入侵植物对土壤N转化相关土壤微生物(尤其是氨氧化细菌与氨氧化古菌)的影响, 探讨了土壤N转化对外来植物入侵的反馈, 并探讨了丛植菌根真菌与外来入侵植物的互相影响。  相似文献   

8.
土壤动物是土壤生态系统中十分活跃的生物类群之一,也是城市草坪生态系统的重要组成部分。由于外来植物白三叶入侵,草坪土壤动物可能受到直接或间接的影响,进而改变城市草坪生态系统功能及过程。研究白三叶入侵对城市草坪生态系统土壤动物的影响,可为进一步了解外来植物入侵机制及城市草坪的建植养护提供理论依据。采用野外调查的试验方法对4种不同入侵程度下城市草坪的土壤动物群落特征和土壤理化性质进行了研究。结果如下:4种不同入侵程度的草坪样地共捕获土壤动物30099只,隶属于19目43科,其中小杆科、线蚓科和跳虫科为优势类群;土壤动物个体数量和类群数量整体表现为中度入侵 > 轻度入侵 > 对照 > 重度入侵,符合中度干扰假说;土壤动物个体数量和类群数量的季节动态主要表现为夏秋较高,冬春较低。CCA分析显示,土壤理化因子中铵态N对土壤动物影响相对较小,可能与白三叶改善了草坪土壤的供N水平并使其不成为土壤动物分布的限制因子有关;同时,土壤理化因子对土壤动物优势类群影响较小,而主要影响常见和稀有类群。总体而言,一定程度的白三叶入侵增加了土壤动物群落的多样性,但当达到重度入侵时,白三叶形成单优群落,减少了植物多样性,进而使土壤动物可获得的生活资源减少,土壤动物群落多样性呈下降趋势;白三叶入侵后通过改变土壤理化性质,影响到土壤动物常见和稀有类群,并最终改变草坪土壤动物的群落结构。  相似文献   

9.
入侵植物三叶鬼针草(Bidens pilosa)对我国农牧业生产造成了重大的损失。本文主要研究三叶鬼针草入侵与不同本地植物竞争对土壤微生物群落结构和土壤养分的影响。利用磷脂脂肪酸方法(phospholipid fatty acids, PLFAs)测定土壤微生物群落组成, 同时测定土壤养分和酶活性, 并利用Canoco4.5软件分析了土壤微生物、土壤养分和土壤酶活性的相关性。结果表明: (1)三叶鬼针草对革兰氏阳性菌、革兰氏阴性菌、丛枝菌根真菌等土壤微生物具有较强的聚集能力, 且其根际土壤聚集的微生物类群与本地植物种类密切相关。(2)三叶鬼针草入侵显著增加了入侵地土壤的有机碳含量, 降低了铵态氮的含量; 土壤中的速效钾、速效磷和硝态氮的含量则与本地植物种类密切相关。(3)相关性分析表明, 16:00和16:1 ω5c对铵态氮的含量影响较大, 而三叶鬼针草入侵地16:00和16:1 ω5c的含量显著高于裸土对照, 进而推测这一状况导致了铵态氮含量的降低。(4) 15:1 anteiso A和18:1 ω5c与速效钾的含量呈显著正相关, 而其含量在狗尾草(Setaria viridis)中显著高于其他处理, 三叶鬼针草与狗尾草混种处理中土壤中速效钾的含量高于其他处理。以上结果说明, 三叶鬼针草通过改变土壤微生物群落结构影响了土壤酶活性和土壤养分, 且这种改变与入侵地本地植物种类有关。  相似文献   

10.
侯玉平  柳林  初航  马淑杰  赵丹  梁荣荣 《生态学报》2015,35(16):5324-5330
生物入侵在世界范围内广泛发生,严重威胁当地生物多样性和生态系统稳定性。植物与土壤之间的相互作用在决定植物的竞争力以及分布格局中起着重要作用,是影响外来植物入侵力和生态系统可入侵性的一个重要方面。目前,有关研究已成为植被生态学与入侵生态学的研究热点。引自北美的外来植物火炬树(Rhus typhina L.)已成为我国北方主要的入侵木本植物之一。比较了火炬树单优林型、火炬树+刺槐(Robinia pseudoacacia L.)混交林、火炬树+麻栎(Quercus acutissima Carruth.)混交林、火炬树+银白杨(Populus alba L.)混交林4种不同林型的土壤微生物群落结构、土壤酶活性和土壤养分含量特征。结果表明:火炬树单优林土壤细菌、放线菌数量明显高于各混交林型,而真菌数量无显著差异;土壤酶活性方面,火炬树单优林脲酶、过氧化氢酶活性高,土壤磷酸酶活性低;火炬树的入侵显著提高了土壤全碳、全氮、全磷和硝态氮含量,同时明显降低了土壤铵态氮含量。硝态氮含量的增高可能与火炬树入侵造成土壤微生物群落组成变化、土壤硝化速率高有关;而火炬树入侵降低了土壤铵态氮含量,说明该物种可能更易于吸收利用铵态氮。以上研究结果表明,火炬树可以改变土壤生态系统的微生物群落组成和土壤酶活性并影响土壤相关营养元素循环,从而可能使其在与当地植物的竞争中获得优势,为自身的入侵创造有利条件。  相似文献   

11.
Exotic plant invasion may alter underground microbial communities, and invasion-induced changes of soil biota may also affect the interaction between invasive plants and resident native species. Increasing evidence suggests that feedback of soil biota to invasive and native plants leads to successful exotic plant invasion. To examine this possible underlying invasion mechanism, soil microbial communities were studied where Ageratina adenophora was invading a native forest community. The plant–soil biota feedback experiments were designed to assess the effect of invasion-induced changes of soil biota on plant growth, and interactions between A. adenophora and three native plant species. Soil analysis showed that nitrate nitrogen (NO3-N), ammonium nitrogen (NH4+-N), and available P and K content were significantly higher in a heavily invaded site than in a newly invaded site. The structure of the soil microbial community was clearly different in all four sites. Ageratina adenophora invasion strongly increased the abundance of soil VAM (vesicular-arbuscular mycorrhizal fungi) and the fungi/bacteria ratio. A greenhouse experiment indicated that the soil biota in the heavily invaded site had a greater inhibitory effect on native plant species than on A. adenophora and that soil biota in the native plant site inhibited the growth of native plant species, but not of A. adenophora. Soil biota in all four sites increased A. adenophora relative dominance compared with each of the three native plant species and soil biota in the heavily invaded site had greater beneficial effects on A. adenophora relative dominance index (20% higher on average) than soil biota in the non-invaded site. Our results suggest that A. adenophora is more positively affected by the soil community associated with native communities than are resident natives, and once the invader becomes established it further alters the soil community in a way that favors itself and inhibits natives, helping to promote the invasion. Soil biota alteration after A. adenophora establishment may be an important part of its invasion process to facilitate itself and inhibit native plants.  相似文献   

12.
Liu W X  Niu H B  Wan F H  Liu B 《农业工程》2010,30(4):196-200
The invasive plant Ageratina adenophora (Sprengel) changed soil microbial communities in the invaded area to facilitate its growth and inhibit native plants. However, little is known about the driving forces underlying the alteration of soil biota. Leachates from root and aerial part (stem and leaves) of A. adenophora were mixed into soil to imitate field invasion processes for evaluation of its impact on invasion of soil microbial community. The results indicated that soil microbial community was significantly changed when the soil taken from the newly-invaded area was treated with A. adenophora root and aerial part leachates for 3 and 5 weeks, respectively. The biota of newly invaded soil treated with concentration of 100 mg/mL A.adenophora leachates was much closer to that of heavily invaded soil, but was significantly different from that of control soil (newly invaded soil without treatment). A.adenophora leachates promoted growth of the seven dominant rhizosphere bacterial species in the invaded soil. The effect of A.adenophora leachates on soil biota and dominant rhizosphere bacteria was positively correlated with the concentration of leachates, however, the effect of root leachates was stronger than the aerial part leachates. It is assumed that A.adenophora change soil microbial community via nutritional and chemical communication, which helps it in better colonization of the invaded soil.  相似文献   

13.
The invasive plant Ageratina adenophora (Sprengel) changed soil microbial communities in the invaded area to facilitate its growth and inhibit native plants. However, little is known about the driving forces underlying the alteration of soil biota. Leachates from root and aerial part (stem and leaves) of A. adenophora were mixed into soil to imitate field invasion processes for evaluation of its impact on invasion of soil microbial community. The results indicated that soil microbial community was significantly changed when the soil taken from the newly-invaded area was treated with A. adenophora root and aerial part leachates for 3 and 5 weeks, respectively. The biota of newly invaded soil treated with concentration of 100 mg/mL A.adenophora leachates was much closer to that of heavily invaded soil, but was significantly different from that of control soil (newly invaded soil without treatment). A.adenophora leachates promoted growth of the seven dominant rhizosphere bacterial species in the invaded soil. The effect of A.adenophora leachates on soil biota and dominant rhizosphere bacteria was positively correlated with the concentration of leachates, however, the effect of root leachates was stronger than the aerial part leachates. It is assumed that A.adenophora change soil microbial community via nutritional and chemical communication, which helps it in better colonization of the invaded soil.  相似文献   

14.
 植物对土壤有效养分的影响是植物竞争取胜的重要生态策略之一, 土壤酶活性对土壤有效养分的变化具有重要作用。该文研究了紫茎 泽兰(Ageratina adenophora)单种(A)、非洲狗尾草(Setaria sphacelata)单种(S)和两物种混种(A+S)群落4种重要的土壤酶活性和土壤养分的 变化及其规律, 并对土壤酶活性与土壤养分进行了相关分析。结果表明: 1)群落S土壤有效氮(NH4+-N和NO3--N)含量高于群落A对应养分含量, 而与群落A+S该养分含量没有显著差异; 群落S土壤有效磷和有效钾含量低于群落A对应指标, 而群落A+S其含量最低。2)群落S、A+S和A土壤蛋 白酶和脲酶活性的高低次序分别为S>A+S>A、A+S>S>A; 群落A+S、S和A磷酸酶活性依次升高; 群落A+S、A和S蔗糖酶活性依次降低。3)在生长 过程中, 3类群落土壤NO3--N、有效磷和有效钾含量在生长初期(5月)最高, 随后逐渐降低; 土壤NH4+-N含量呈现单峰趋势, 在生长后期(9月)最 高。3类群落土壤蛋白酶和蔗糖酶活性随生长时间推移而升高, 在生长末期(11月)最高; 土壤磷酸酶和脲酶酶活性在生长过程中呈现单峰趋势, 在生长旺盛期(7月)最高。3类群落间土壤酶活性与土壤肥力具有较一致的相关性。由此推断, 非洲狗尾草对土壤含氮化合物的活化能力比紫茎 泽兰强, 且在种间竞争中能够强烈抑制紫茎泽兰对土壤含磷、含钾化合物的活化能力是其竞争取胜的可能原因; 不同植物群落土壤酶活性的差 异是引起土壤有效养分变化的重要驱动机制之一。  相似文献   

15.
为明确不同入侵地植物群落和土壤生态对黄顶菊入侵的反馈机制,选取天津静海(JH)、河北沧州(CZ)、河北衡水(HS)及河南安阳(AY)4个黄顶菊入侵典型区域,研究黄顶菊对不同入侵地植物群落多样性、土壤理化及土壤微生物群落结构的影响,并进一步揭示植物群落、土壤养分和土壤微生物之间的相关关系。结果表明,黄顶菊入侵显著降低了JH、CZ和HS的植物群落多样性指数(P0.05),改变了四个地区的土壤理化性质,显著升高了不同入侵地真菌PLFA的含量、总PLFA的含量、真菌/细菌和革兰氏阴性菌/革兰氏阳性菌(P0.05),降低了土壤微生物的Margalef丰富度指数(P0.05),但均存在地区间差异;RDA和相关分析的结果表明,硝态氮、全氮的含量对植物群落的影响较大,而铵态氮的含量对土壤微生物群落结构的影响较大,除丰富度指数外,植物群落与土壤微生物群落的多样性指数之间存在显著的负相关关系(P0.05)。总之,黄顶菊改变了入侵地植物群落多样性,并且对入侵地土壤理化性质和土壤微生物群落结构产生了显著影响,且存在地区差异。本研究将为更好的理解外来植物的入侵机制及制定相应的防控策略提供理论依据。  相似文献   

16.
Plant invasions have dramatic aboveground effects on plant community composition, but their belowground effects remain largely uncharacterized. Soil microorganisms directly interact with plants and mediate many nutrient transformations in soil. We hypothesized that belowground changes to the soil microbial community provide a mechanistic link between exotic plant invasion and changes to ecosystem nutrient cycling. To examine this possible link, monocultures and mixtures of exotic and native species were maintained for 4 years in a California grassland. Gross rates of nitrogen (N) mineralization and nitrification were quantified with 15N pool dilution and soil microbial communities were characterized with DNA‐based methods. Exotic grasses doubled gross nitrification rates, in part by increasing the abundance and changing the composition of ammonia‐oxidizing bacteria in soil. These changes may translate into altered ecosystem N budgets after invasion. Altered soil microbial communities and their resulting effects on ecosystem processes may be an invisible legacy of exotic plant invasions.  相似文献   

17.
The complexities of the relationships between plant and soil microbial communities remain unresolved. We determined the associations between plant aboveground and belowground (root) distributions and the communities of soil fungi and bacteria found across a diverse tropical forest plot. Soil microbial community composition was correlated with the taxonomic and phylogenetic structure of the aboveground plant assemblages even after controlling for differences in soil characteristics, but these relationships were stronger for fungi than for bacteria. In contrast to expectations, the species composition of roots in our soil core samples was a poor predictor of microbial community composition perhaps due to the patchy, ephemeral, and highly overlapping nature of fine root distributions. Our ability to predict soil microbial composition was not improved by incorporating information on plant functional traits suggesting that the most commonly measured plant traits are not particularly useful for predicting the plot‐level variability in belowground microbial communities.  相似文献   

18.
Aims Changes in soil microbial communities after occupation by invasive alien plants can represent legacy effects of invasion that may limit recolonization and establishment of native plant species in soils previously occupied by the invader. In this study, for three sites in southern Germany, we investigated whether invasion by giant goldenrod (Solidago gigantea) leads to changes in soil biota that result in reduced growth of native plants compared with neighbouring uninvaded soils.Methods We grew four native plant species as a community and treated those plants with soil solutions from invaded or uninvaded soils that were sterilized, or live, with live solutions containing different fractions of the soil biota using a decreasing sieve mesh-size approach. We measured aboveground biomass of the plants in the communities after a 10-week growth period.Main Findings Across all three sites and regardless of invasion, communities treated with <20 μm soil biota or sterilized soil solutions had significantly greater biomass than communities treated with the complete soil biota solution. This indicates that soil biota>20 μm are more pathogenic to the native plants than smaller organisms in these soils. Across all three sites, there was only a non-significant tendency for the native community biomass to differ among soil solution types, depending on whether or not the soil was invaded. Only one site showed significant differences in community biomass among soil solution types, depending on whether or not the soil was invaded; community biomass was significantly lower when treated with the complete soil biota solution than with soil biota <20 μm or sterilized soil solutions, but only for the invaded soil. Our findings suggest that efforts to restore native communities on soils previously invaded by Solidago gigantea are unlikely to be hindered by changes in soil microbial community composition as a result of previous invasion.  相似文献   

19.
Soil legacy effects are commonly highlighted as drivers of plant community dynamics and species co‐existence. However, experimental evidence for soil legacy effects of conditioning plant communities on responding plant communities under natural conditions is lacking. We conditioned 192 grassland plots using six different plant communities with different ratios of grasses and forbs and for different durations. Soil microbial legacies were evident for soil fungi, but not for soil bacteria, while soil abiotic parameters did not significantly change in response to conditioning. The soil legacies affected the composition of the succeeding vegetation. Plant communities with different ratios of grasses and forbs left soil legacies that negatively affected succeeding plants of the same functional type. We conclude that fungal‐mediated soil legacy effects play a significant role in vegetation assembly of natural plant communities.  相似文献   

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