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1.
外来植物成功入侵与菌根共生体存在着密不可分的关系,丛枝菌根真菌(AMF)侵染率是反映其侵染植物情况的重要指标,影响侵染率的因素很多,但是入侵植物与本地植物互作对AMF侵染率的影响目前还不清楚。因此,本研究以外来入侵植物黄顶菊Flaveria bidentis、豚草Ambrosia artemisiifolia、三叶鬼针草Bidens pilosa和本地植物狗尾草Setaria viridis、黄香草木犀Melilotus officinalis、藜Chenopodium album为研究对象,设置入侵植物单种处理、本地植物单种处理、每种入侵植物分别与本地植物两两混种处理以及每种入侵植物同时与所有本地植物混种处理,观察测定不同处理下入侵植物与本地植物根系丛枝、泡囊、菌丝及总侵染率,比较研究本地植物种类变化对入侵植物和本地植物根系AMF侵染率的影响,以及3种入侵菊科植物对本地植物AMF侵染率的影响规律是否一致。结果表明,与入侵植物单种相比,除豚草与藜、豚草同时与3种本地植物混种两个处理中,豚草根系的AMF菌丝及总侵染率显著增加外,其余所有处理中入侵植物总侵染率均无显著差异;与狗尾草或黄香草木犀单种相比,每种入侵植物同时与所有本地植物混种处理中,本地植物狗尾草和黄香草木犀根系上的AMF菌丝及总侵染率均显著降低,即随本地植物种类数目的增加,对本地植物根系的菌丝及总侵染率存在显著抑制作用,而对入侵植物无显著影响。  相似文献   

2.
氮水平和竞争对互花米草与芦苇叶特征的影响   总被引:1,自引:0,他引:1       下载免费PDF全文
 互花米草 (Spartina alterniflora) 和芦苇 (Phragmites australis) 是滨海盐沼湿地的多年生草本植物,从世界范围来看,它们二者具有区域性的相互入侵特征,因此研究生境条件对两物种互侵机制的影响是一个十分有意义的生态学命题。该文运用随机区组实验设计方法,模拟海滩环境、构建人工种群、控制可变因子,研究了外来种互花米草与本地种芦苇分别单种和混种时,叶特征对不同氮水平、不同植株密度的响应。结果表明:随着氮水平的升高,互花米草和芦苇的叶面积无论是在单种还是混种情况下都显著增加 (p<0.05),但混种条件下芦苇的叶面积在高氮水平下增幅减少,这与高氮状况下互花米草与芦苇的竞争加剧有关;氮水平对单种中两种植物的叶数影响最显著 (p<0.01),对混种中互花米草的叶数和芦苇的叶宽影响最大 (p<0.05)。植株密度增加导致种内和种间竞争加剧,无论在单种还是混种处理下,都造成两种植物叶面积的显著减少 (p<0.05)。单种处理中, 两物种的叶数受密度的响应最显著 (p<0.05);而混种处理中芦苇对互花米草的竞争显著减小了互花米草的叶宽和叶数(p<0.05),互花米草对芦苇的竞争则显著减小了芦苇 的叶长、叶宽和叶数 (p<0.05)。两种植物的竞争结果受到氮营养的调控,低、高氮水平下互花米草的种间竞争能力大于芦苇,中氮水平下则是芦苇的种间竞争能力大于互花米草。高氮水平下互花米草通过叶面积的快速增加抑制了芦苇的叶生长,使其叶面积减少,从而在竞争中占据优势,这可能是互花米草入侵我国海滩芦苇种群的机制之一。  相似文献   

3.
【背景】丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)能促进植物的养分吸收及生长发育。入侵中国华南地区的外来入侵植物南美蟛蜞菊(Wedelia trilobata)常分布于养分匮乏的荒地,却能迅速生长并排挤本地植物而快速扩张领地。【目的】探究丛枝菌根真菌是否促进南美蟛蜞菊的生长与竞争能力。【方法】采用南美蟛蜞菊及其同属本地植物蟛蜞菊(Wedelia chinensis)的盆栽对比控制试验,并设置接种及不接种AMF变形球囊霉(Glomus versiforme)、不同磷营养水平以及单种或混种的种植方式3种处理对两种植物的生长及竞争能力进行比较。【结果】AMF均能侵染上述两种植物,并且AMF对南美蟛蜞菊根系的侵染率显著高于其对蟛蜞菊根系的侵染,尤其是在低磷水平下南美蟛蜞菊的菌根侵染率更高,而且AMF的侵染显著促进了低磷水平下南美蟛蜞菊的生长及其对蟛蜞菊的竞争能力。【结论】丛枝菌根真菌能够促进南美蟛蜞菊的生长,增强其对本地植物的竞争优势,该效应很可能对外来植物南美蟛蜞菊的成功入侵产生一定的作用。  相似文献   

4.
为了解广州地区7种菊科(Compositae)入侵植物与丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)的互作共生关系,调查了这7种菊科入侵植物在4种生境中的AMF侵染和根际土壤孢子密度,并分析土壤因子对AMF的影响。结果表明,7种入侵植物根内均受到AMF侵染,根际土壤中均检测到AMF孢子;AMF侵染在宿主间差异显著,生境间的差异不显著;孢子密度在生境和宿主间的差异均显著,人工绿地、农田果园的AMF孢子密度均显著高于森林周边和滨海地带。相关性分析表明,农田果园生境的根际土壤孢子密度与土壤有机质含量呈显著负相关关系;森林周边生境的AMF总侵染率与土壤全氮呈极显著正相关关系;人工绿地的AMF总侵染率与土壤速效氮含量呈显著负相关关系;滨海地带的AMF总侵染率与土壤有效磷含量呈显著负相关关系。这些对理解菊科植物入侵机理具有非常重要的作用。  相似文献   

5.
外来植物与入侵地土壤丛枝菌根真菌(AMF)的互作和反馈已被认为是许多入侵植物的重要入侵机制之一。为进一步探究入侵植物紫茎泽兰(Ageratina adenophora)竞争替代本地植物过程中AMF的作用,本研究首先测定了林下和林地边缘两类生境中紫茎泽兰和本地植物的AMF侵染率和AMF含量,结果表明,2种生境中紫茎泽兰的菌根侵染率和AMF含量均显著高于本地植物,且菌根侵染率与AMF含量呈显著正相关。温室盆栽试验结果进一步表明,接种AMF显著促进了紫茎泽兰的生长,且对硝态氮和有效磷的吸收能力优于本地植物香茶菜(Rabdosia amethystoides),同时降低了竞争中本地植物香茶菜的菌根依赖性,提高了紫茎泽兰对香茶菜的竞争优势度。本研究进一步证实AMF有利于促进紫茎泽兰的竞争性扩张。  相似文献   

6.
福建红树林植物丛枝菌根侵染研究   总被引:1,自引:0,他引:1  
2010年5月和12月,对福建沿海3个红树林生长区(洛阳江、九龙江口、漳江口)的红树林植物丛枝菌根(AM)侵染状况进行研究。结果表明:(1)红树林生长区中6种植物根内均发现AMF侵染结构,其中桐花树、秋茄、鱼藤和芦苇的丛枝为Arum(疆南星)型;(2)6种植物的丛枝菌根侵染率差异较大,老鼠簕的侵染率最高,鱼藤最低;(3)桐花树和秋茄的丛枝菌根侵染率呈显著差异,而其在不同生长区之间无差异;(4)桐花树和秋茄的丛枝菌根侵染率在不同时间呈显著差异,而钝草的丛枝菌根侵染率在不同时间的差异不显著。  相似文献   

7.
采用盆栽方法研究了增氮条件下丛枝菌根真菌(AMF)对无芒稗(Echinochloa crusgallivar.mitis L.)和陆稻(Oryza sativa L.)相互作用的调节.结果表明:在单种条件下,无芒稗的菌根侵染率增加,陆稻的菌根侵染率降低;无AMF和接种AMF处理陆稻的生物量分别提高13.48%和42.35%,总磷吸收分别提高2.55%和4.07%,总氮吸收分别提高62.09%和30.35%;无芒稗的生物量分别提高15.65%和20.24%,总磷吸收分别提高4.06%和3.88%,总氮吸收分别提高30.35%和15.10%.在混种条件下,无芒稗的菌根侵染率增加,而陆稻无显著变化;无AMF和接种AMF的无芒稗与陆稻的生物量比值降低,总氮吸收比值无显著变化,无AMF处理的总磷吸收比值增加,而接种AMF处理降低.表明增氮条件下AMF提高了无芒稗对陆稻的竞争.  相似文献   

8.
测定了崇明东滩湿地典型植物群落内芦苇和互花米草各器官及土壤中的N、P含量和N∶P,揭示了它们的季节性动态,并对其N、P利用对策进行了生态化学计量学分析.结果表明:两种植物的N、P含量差异显著且芦苇>互花米草;不同植物以及同一植物不同器官的N、P含量随生长节律发生明显变化;N、P含量的器官分配模式对于芦苇和互花米草均是叶>茎>根;两种植物地上部分和地下部分N、P含量5月>9月>7月;芦苇N、P积累量>互花米草;2种植物地上部分N、P含量差异显著;互花米草生境土壤各月份N含量均高于芦苇生境土壤;P含量仅在5月份高于芦苇生境土壤,其它月份均低于芦苇生境土壤.芦苇叶片N含量与生境土壤N含量相关不显著,叶片P含量与土壤P含量显著正相关;互花米草叶片N含量与土壤N含量极显著正相关,叶片P含量与土壤P含量相关不显著.芦苇和互花米草叶片N∶P与土壤N、P含量及N∶P间相关均不显著.芦苇在生长初期和生长末期的N∶P<14,表明其生长受到N限制;处于生长旺季时,14<N∶P<16,表明其受到N、P共同限制.互花米草在各月份的N∶P<14,说明其主要受到N限制.总体而言,N素是芦苇和互花米草净初级生产力的主要而经常性的限制因子.  相似文献   

9.
种间相互作用是影响湿地植物群落构建的关键因子,其形式、强度和机制可能随着生长发育的过程而发生改变。种子萌发是植物生命周期的关键环节,一定程度上决定了植物种群分布和群落结构。野外种子萌发过程受到邻近同种或异种种子间相互作用的影响,但对于种子萌发过程中种内、种间相互作用强度及其影响因素的了解仍十分有限。该研究通过培养皿萌发实验探讨了种子密度(每皿80粒、每皿160粒)及比例(单种、3:1混种、2:2混种、1:3混种)对互花米草(Spartina alterniflora)、海三棱藨草(Scirpus×mariqueter)、芦苇(Phragmites australis)种子萌发率、平均萌发时间的影响,并采用相对邻株效应(RNE)评估了这3个物种的种内、种间相互作用强度。结果表明,密度对互花米草、海三棱藨草、芦苇种子的萌发率均有一定的促进作用。与互花米草混种时,芦苇种子在占比最低(25%)处理下的平均萌发时间显著长于单种及其他混种比例处理。3种植物种子的竞争能力没有明确的等级关系,存在非传递性竞争,萌发时海三棱藨草相对互花米草具有一定的竞争优势,互花米草相对芦苇具有一定优势,而芦苇的竞争能...  相似文献   

10.
明确丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)侵染率对喀斯特坡地坡位与物种的响应及其关键影响因子,是合理利用土壤AMF促进喀斯特植被恢复的前提。该研究在充分调查喀斯特峰丛洼地典型灌丛坡地环境背景信息的基础上,采用曲利苯蓝染色-镜检法检测并计算典型灌木黄荆(Vitex negundo)、红背山麻杆(Alchornea trewioides)和火棘(Pyracantha fortuneana)根系AMF侵染频度、侵染强度和丛枝丰度等侵染率参数。结果表明:(1)相同坡位火棘的侵染频度、侵染强度和丛枝丰度均显著低于红背山麻杆和黄荆;下坡位黄荆和火棘的侵染强度均高于中、上坡位,而中坡位红背山麻杆的丛枝丰度显著高于上、下坡位(P<0.05)。(2)物种显著影响AMF侵染频度、侵染强度和丛枝丰度,坡位显著影响AMF侵染强度,物种与坡位的交互作用仅对AMF丛枝丰度有显著影响(P<0.05)。(3)影响AMF侵染率的关键土壤因子是土壤深度和全钾含量(P<0.05)。因此,合理利用土壤AMF促进喀斯特地区植被恢复需要考虑地形与物种的选择,并应注重兼...  相似文献   

11.
研究了培养基质、储藏方式和盐度对3种海滨植物互花米草(Spartina alterniflora)、盐地碱蓬(Suaeda salsa)和芦苇(Phragmites australis)种子萌发的影响,探索在潮间带环境下海滨植物种子萌发适应策略。结果表明:3种植物的干藏种子和湿藏芦苇种子随着盐度的升高,萌发率和萌发速率均显著下降,湿藏互花米草和盐地碱蓬种子在各盐度下萌发率和萌发速率差异不显著。各盐度-土培-干藏互花米草,中、高盐度-土培-干藏盐地碱蓬,土培各处理,中、高盐度-水培-干藏,高盐度-水培-湿藏芦苇种子萌发失败。湿藏提高了各盐度处理下土培互花米草,中、高盐度-水培和土培盐地碱蓬,淡水、中盐度-水培芦苇种子的萌发率和萌发速率。干藏互花米草种子在中、高盐度和土埋条件下种子的萌发受到抑制,限制了互花米草向高潮带与潮上带的扩展;而经常受潮水浸淹保持湿润的种子能抵抗高盐和泥沙沉积,导致互花米草种群逐步向低潮带方向发展;湿藏芦苇种子在淡水中萌发率和萌发速率最高,当潮上带盐度降低时,芦苇具有很强的竞争优势,但是对盐度和土埋敏感,限制了其向海的拓展;盐地碱蓬在中、高盐度和土培条件下萌发速率最高,快速萌发的适应策略和广适应性在盐地碱蓬占据高潮带和中潮带广大区域的过程中起到了重要的作用。  相似文献   

12.
Effects of arbuscular mycorrhizal fungi (AMF) and salt stress on nutrient acquisition and growth of two tomato cultivars exhibiting differences in salt tolerance were investigated. Plants were grown in a sterilized, low-P (silty clay) soil-sand mix. Salt was applied at saturation extract (ECe) values of 1.4 (control), 4.9 (medium) and 7.1 dS m–1 (high salt stress). Mycorrhizal colonization occurred irrespective of salt stress in both cultivars, but AMF colonization was higher under control than under saline soil conditions. The salt-tolerant cultivar Pello showed higher mycorrhizal colonization than the salt-sensitive cultivar Marriha. Shoot dry matter (DM) yield and leaf area were higher in mycorrhizal than nonmycorrhizal plants of both cultivars. Shoot DM and leaf area but not root DM were higher in Pello than Marriha. The enhancement in shoot DM due to AMF inoculation was 22% and 21% under control, 31% and 58% under medium, and 18% and 59% under high salinity for Pello and Marriha, respectively. For both cultivars, the contents of P, K, Zn, Cu, and Fe were higher in mycorrhizal than nonmycorrhizal plants under control and medium saline soil conditions. The enhancement in P, K, Zn, Cu, and Fe acquisition due to AMF inoculation was more pronounced in Marriha than in the Pello cultivar under saline conditions. The results suggest that Marriha benefited more from AMF colonization than Pello under saline soil conditions, despite the fact that Pello roots were highly infected with the AMF. Thus, it appears that Marriha is more dependent on AMF symbiosis than Pello. Accepted: 22 January 2001  相似文献   

13.
An invasive variety of Phragmites australis (Poaceae, common reed), the M haplotype, has been implicated in the spread of this species into North American salt marshes that are normally dominated by the salt marsh grass Spartina alterniflora (Poaceae, smooth cordgrass). In some European marshes, on the other hand, Spartina spp. derived from S. alterniflora have spread into brackish P. australis marshes. In both cases, the non-native grass is thought to degrade the habitat value of the marsh for wildlife, and it is important to understand the physiological processes that lead to these species replacements. We compared the growth, salt tolerance, and osmotic adjustment of M haplotype P. australis and S. alterniflora along a salinity gradient in greenhouse experiments. Spartina alterniflora produced new biomass up to 0.6 M NaCl, whereas P. australis did not grow well above 0.2 M NaCl. The greater salt tolerance of S. alterniflora compared with P. australis was due to its ability to use Na(+) for osmotic adjustment in the shoots. On the other hand, at low salinities P. australis produced more shoots per gram of rhizome tissue than did S. alterniflora. This study illustrates how ecophysiological differences can shift the competitive advantage from one species to another along a stress gradient. Phragmites australis is spreading into North American coastal marshes that are experiencing reduced salinities, while Spartina spp. are spreading into northern European brackish marshes that are experiencing increased salinities as land use patterns change on the two continents.  相似文献   

14.
以濒危植物七子花二年生幼苗为研究材料,采用盆栽试验方法,研究干旱胁迫和接种丛枝菌根真菌(AMF)处理对幼苗不同器官C、N、P化学计量关系和非结构性碳水化合物(NSC)含量的影响。试验共设计4个处理:对照(CK)、干旱胁迫(D)、接种AMF(AMF)、干旱胁迫和接种AMF(D+AMF)。结果表明: 在干旱胁迫下七子花根系AMF的侵染率显著下降,但接种AMF处理植株的株高、叶片数显著高于未接种处理。接种AMF显著提高了干旱胁迫下植株根、叶可溶性糖和NSC含量及茎、叶淀粉含量,且茎和叶可溶性糖与淀粉比显著下降。干旱胁迫导致植株C含量在根和叶中显著增加,P含量在茎中显著减少;与干旱胁迫相比,胁迫下接种AMF植株根、茎、叶P含量及叶C含量显著提高,而根C、N含量及茎C含量显著降低。胁迫下接种AMF植株根、茎C∶N、C∶P、N∶P和叶N∶P均显著低于单一胁迫处理。NSC与C∶N∶P计量比的相关性分析表明,根、叶P含量与可溶性糖和NSC含量呈显著正相关,茎P含量与淀粉和NSC含量呈显著正相关,各器官N∶P与NSC含量呈显著负相关。综上,干旱胁迫显著抑制了七子花幼苗的生长,接种AMF通过提高植株根和叶的可溶性糖含量、根的可溶性糖/淀粉,增加地上部分淀粉含量,促进P元素吸收和降低各器官N∶P来增强植株耐旱性,从而提高七子花幼苗在干旱环境中的存活率。  相似文献   

15.
山西历山珍稀药用植物AM真菌资源与土壤因子的关系   总被引:2,自引:0,他引:2  
以山西历山自然保护区暴马丁香、连香树、南方红豆杉和领春木4种珍稀药用植物为材料,研究其根际土壤中丛枝菌根真菌(AMF)的菌根结构类型和种属分布,同时分析土壤因子与其侵染率和孢子密度的关系。结果表明:(1)暴马丁香菌根类型为中间型(I-型),连香树和领春木为重楼型(P-型),南方红豆杉为疆南星型(A-型);4种植物根际共鉴定AMF 27种,分别隶属于球囊霉属(Glomus)、无梗囊霉属(Acaulospora)、盾巨孢囊霉属(Scutellos-pora)、多孢囊霉属(Diversispora)和原囊霉属(Archaeospora)5属,其中Glomus为优势属。(2)pH与暴马丁香和领春木的侵染率和孢子密度呈正相关,但与连香树和南方红豆杉呈负相关;速效磷与暴马丁香、南方红豆杉和领春木的侵染率和孢子密度呈正相关,但与连香树呈负相关;碱解氮、有机质与暴马丁香、连香树和领春木的侵染率和孢子密度呈正相关,但与南方红豆杉呈负相关。(3)4种药用植物的菌根侵染率主要受其根际土壤碱解氮的影响,而根际AMF孢子密度主要受根际土壤pH制约。可见,历山自然保护区内AMF资源丰富,多样性程度也较高;宿主植物不同,土壤因子对其侵染率和孢子密度的影响也不同。  相似文献   

16.
Responses of Puccinellia distans, a halophytic grass to low (50 mM) and high (200 mM) NaCl salinity, were studied in a sand culture experiment without or with inoculation by arbuscular mycorrhizal fungus (AMF), Claroideoglomus etunicatum isolated from its saline habitat. Plant biomass was not influenced by salinity levels, while a tendency to a higher biomass was observed in AMF plants under both control and saline conditions. Leaf photosynthesis increased by both salinity and AMF inoculation. Despite higher transpiration rate, AMF plants had higher water-use efficiency under sever saline conditions. AMF inoculation decreased proline concentration, but increased significantly leaf osmotic potential. Antioxidative enzymes responded differently to the salt and AMF treatments depending on the salt concentration and plant organ. Nonetheless, salt-induced malondialdehyde accumulation in the leaves diminished by AMF colonization. K and Ca contents were not affected by salt, while fungal colonization increased K in the roots and Ca in both leaves and roots. Our results indicated that enhancement of photosynthesis and ion homeostasis is involved in the tolerance of P. distans to both low and high salinity. AMF inoculation increased plants’ tolerance by augmentation of the above mechanisms accompanied by improvement of water relations and protection against oxidative damage in the leaves.  相似文献   

17.
Arbuscular mycorrhizal fungi (AMF) are root obligate biotrophs that provide the host with nutrients and pathogen protection, in exchange of photosynthetic products. A decline in AMF diversity can reduce the overall benefit for host plants. A sustainable strategy to re-establish AMF diversity is to supply the target soil with AMF inoculants. After inoculation, it is essential to verify whether the inoculants successfully colonize the host plant and persist, and if the resident AMF community is affected. The AMF components of a microbial inoculum (including other saprotrophs) that was applied to maize were identified and traced in field by 454-pyrosequencing of the partial rRNA 18S gene. In addition, mycorrhizal colonization and plant biomass were monitored in inoculated and non-inoculated maize. The inoculated AMF taxa failed to colonize roots and lacked soil persistence. Nevertheless, the inoculation process reduced species dominance and increased diversity in the pre-existing AMF community. No differences were seen between mycorrhizal colonization in treated and control maize. We suggest that the slightly significant increase in treated plant biomass was potentially due to (i) marginally colonizing inoculated AMF that remained unseen and other saprotroph inoculants applied and/or (ii) the effect of inoculation on the pre-existing AMF community in treated maize roots.  相似文献   

18.
Legume roots in nature are usually colonized with rhizobia and different arbuscular mycorrhizal fungi (AMF) species. Light microscopy that visualizes the presence of AMF in roots is not able to differentiate the ratio of each AMF species in the root and nodule tissues in mixed fungal inoculation. The purpose of this study was to characterize the dominant species of mycorrhiza in roots and nodules of plants co-inoculated with mycorrhizal fungi and rhizobial strains. Glomus intraradices (GI), Glomus mosseae (GM), their mix (GI + GM), and six Mesorhizobium ciceri strains were used to inoculate chickpea. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to assess occupancy of these fungal species in roots and nodules. Results showed that GI molecular ratio and relative density were higher than GM in both roots and nodules. These differences in molecular ratio and density between GI and GM in nodules were three folds higher than roots. The results suggested that M. ciceri strains have different effects on nodulation and mycorrhizal colonization pattern. Plants with bacterial S3 and S1 strains produced the highest root nodulation and higher fungal density in both the roots and nodules.  相似文献   

19.
闽江河口湿地枯落物分解及主要影响因子   总被引:3,自引:0,他引:3  
以闽江河口湿地挺水植物本地种芦苇和入侵种互花米草的花和叶枯落物为研究对象,采用分解袋法分析其分解过程及主要影响因素.结果表明:立枯分解(0~90 d)是2种湿地盐沼植物重要的分解阶段,芦苇和互花米草的花和叶质量损失率分别为(15.0±3.5)%、(13.3±1.1)%和(31.9±1.1)%、(20.8±1.4)%.倒伏分解阶段(91 ~210 d),芦苇和互花米草的花和叶质量损失率分别为(69.5±0.6)%、(71.5±2.5)%和(76.8±1.9)%、(67.5±2.1)%.在立枯分解阶段,2种挺水植物枯落物的分解速率与C/N呈正相关,与N/P呈负相关,分解过程受到P的限制程度较大.倒伏分解阶段,枯落物C/N、C/P和N/P的影响降低,而大气温湿度、土壤水分、酸碱度、盐度和沉积物特性等的影响加大.不同分解阶段枯落物分解影响因子的差异主要与其所处的微域环境和潮汐因素有关.  相似文献   

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