Invasive plant Ageratina adenophora(Sprengel)R.King&H.Robinson has invaded majority of the temperate forests in Kumaun,Central Himalaya.Information on A.adenophora invaded forest types,their structural attributes,...Invasive plant Ageratina adenophora(Sprengel)R.King&H.Robinson has invaded majority of the temperate forests in Kumaun,Central Himalaya.Information on A.adenophora invaded forest types,their structural attributes,population demography and regeneration status are still at rudimentary level.Considering this,the present study was conducted to assess the impacts of A.adenophora on vegetational attributes and regeneration status of three forest types,viz.,Oak(Quercus oblongata D.Don),Pine(Pinus roxburghii Sarg.)and Cypress(Cupressus torulosa D.Don).We selected three sites for each forest type and each site was further purposively stratified into paired sampling plots of 1 ha each i.e.,A.adenophora invaded and uninvaded sites.Our results showed large densities of cut stumps or felled trees throughout invaded sites,but with fewer fire signs in comparison to uninvaded sites.In uninvaded sites,total density and basal area calculated for woody species were relatively higher than those in invaded sites,although results were insignificant(p>0.05).With the exception for Cypress forests,vegetation indices showed low woody species richness and diversity in invaded Oak and Pine forests.Also,regeneration of Q.oblongata,P.roxburghii and C.torulosa tree species did not differ significantly(p>0.05)between invaded and uninvaded sites.These insignificant differences clearly imply that A.adenophora's presence has not entirely changed the perennial plant communities in terms of composition,structure and natural regeneration.However,tree species with poor or no regeneration status requires special attention and needs management strategies involving control of invasive species in forest ecosystems.展开更多
Rhizosphere microbial communities play important roles in facilitating or inhibiting the establishment of exotic species.Since some invasive plants interact with soil microbial communities such as rhizosphere bacteria...Rhizosphere microbial communities play important roles in facilitating or inhibiting the establishment of exotic species.Since some invasive plants interact with soil microbial communities such as rhizosphere bacteria,changes triggered by rhizosphere bacteria may alter competitive interactions between exotic and native plants.This study compared the Bacillus cereus content in soils with different degrees of Ageratina adenophora invasion,and investigated the effects of A.adenophora allelochemicals on B.cereus growth and soil characteristics and the feedback effects of B.cereus on A.adenophora growth.Bacillus cereus content in the rhizosphere of A.adenophora increased with intensification of the invasion process,and newly invaded soil contained almost twice as much bacteria as noninvaded soil.When rhizosphere soil was added to the root exudates of A.adenophora,the contents of B.cereus were twice as much as the control,except on the first day.Certain soil parameters increased significantly,such as ammonium nitrogen(NH_(4)^(+)-N)and available phosphorus(AP),which were increased by 41 and 27%,respectively.Soil treatment with B.cereus promoted the degradation of two allelochemicals from the rhizosphere of A.adenophora,amorpha-4,7(11)-dien-8-one and 6-hydroxy-5-isopropy1-3,8-dimethyl-4 a,5,6,7,8,8 ahexahydraphthalen-2(1 H)-one,to varying degrees;and increased the germination rate by 50%,root length by 117%,shoot length by 48%and fresh weight by 81%for A.adenophora compared to those of untreated soil.Our results confirmed that the invasion of A.adenophora will promote an increase of B.cereus,a beneficial rhizosphere bacterium,which in turn induces a positive feedback effect on A.adenophora.展开更多
Allelopathy of Ageratina adenophora plays an important role in its invasion. However, we have little knowledge of its allelpathic effects on ferns. In Petri dish bioassays, the inhibitory potential of aqueous leachate...Allelopathy of Ageratina adenophora plays an important role in its invasion. However, we have little knowledge of its allelpathic effects on ferns. In Petri dish bioassays, the inhibitory potential of aqueous leachates from roots, stems and leaves of A. adenophora was studied on the spore germination and gametophyte development of Macrothelypteris torresiana. All leachatss inhibited the spore germination and growth of the first rhizoid of M. torresiana and inhibitory effects increased with increasing leachate concentrations. Root leachates proved most inhibitory. Gametophyte rhizoids of M. torresiana treated with stem and leaf leachates of A. adenophora were erect, which was similar to those of the control. However, gametophyte rhizoids of M. torresiana treated with root leachates of A. adenophora were erect, but also curving or swollen. Moreover, curving and swollen rhizoids increased with increasing concentrations. As time went by, rhizoids treated with root leachates were not so curved and the swelling almost disappeared. Possible causes are discussed in the present study. The increasing concentrations of leaf leachates also delayed the stages of gametophyte development. With the treatment of root leachates, the delay was more obvious. Thus A. adenophora inhibited the spore germination and gametophyte development of M. torresiana and the root leachates were most inhibitory.展开更多
Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investi...Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investigate the soil chemical and microbiological properties along an altitudinal gradient on a mountain colonized by the invader Ageratina adenophora.Rhizosphere soil of A.adenophora was collected over an altitudinal gradient(1400–2400 m)in Ailao Shan,China.We determined soil organic carbon(C),nutrient contents,enzyme activities,bacterial community composition as well as C and nitrogen(N)contents of the plant roots.Ecoenzymatic stoichiometric indices were calculated to estimate the relative C,N or P limitations of the microbial community.There was a significant effect of altitude on soil organic C in the rhizosphere,and a turning point in these measured variables was detected at an altitude of 2000 m.At low elevations,the rapid growth of invasive plants depleted the deficient phosphorus(P)in tropical soils,leading to microbial P limitation;at high elevations,microbes invested more energy to obtain C from resistant litter,leading to microbial C limitation.Bacterial beta diversity and soil pH contributed most to the altitudinal differences in ecoenzymatic stoichiometry,and Proteobacteria and Acidobacteria were the dominant bacterial phyla that determined the nutrient uptake status of microorganisms.These results demonstrate how microbial nutrient acquisition belowground of A.adenophora along an altitudinal gradient,which could contribute to further knowledge about the effects of altitude on biological invasion.展开更多
Aims Crofton weed,with a subtropical origin,has successfully invaded in diverse habitats that belong to different climate zones in southwest China.We tested whether local adaptation plays an important role in the succ...Aims Crofton weed,with a subtropical origin,has successfully invaded in diverse habitats that belong to different climate zones in southwest China.We tested whether local adaptation plays an important role in the successful invasion of crofton weed in heterogeneous environments.Methods Five populations from different habitats with an altitude ranging from 678 to 2356 m were selected.Plant height,biomass,seed yield and seed germination capability of these populations were investigated in the field.greenhouse and reciprocal transplant experiments with the five populations were conducted,and all the above characters were measured and compared among these populations.Important Findings Plant height,biomass,seed yield and seed germination rate were each significantly different among the five populations in field.However,there was no difference among these populations in the greenhouse experiment.In the reciprocal transplant experiment,plants from the five populations responded similarly to different habitats in the field,indicat-ing lack of local adaptation.Instead,phenotypic plasticity likely plays a key role in the invasion success of crofton weed in different habitats.展开更多
In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation,the formation of single dominant populat...In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation,the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion,interaction and competition between inter-and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.展开更多
紫茎泽兰(Ageratina adenophora)是多年生草本植物,主要分布于热带与温带,是入侵植物中危害最严重的物种之一。基于中国知网和Web of Science核心库集,对已发表的紫茎泽兰相关文献进行计量分析,旨在了解国内外对该植物防治、利用以及研...紫茎泽兰(Ageratina adenophora)是多年生草本植物,主要分布于热带与温带,是入侵植物中危害最严重的物种之一。基于中国知网和Web of Science核心库集,对已发表的紫茎泽兰相关文献进行计量分析,旨在了解国内外对该植物防治、利用以及研究的现状和发展趋势,明确研究前沿与热点问题,为进一步开展紫茎泽兰相关研究提供参考。结果表明,紫茎泽兰是国内外生态与环境保护领域重点研究的入侵物种。我国科研工作者在其防控、利用研究中发挥着重大作用,但科研机构、研究人员间的交流与合作有待加强,同时学科交叉发展不足。近年来该领域的研究热点主要集中于探究紫茎泽兰的性能及其开发利用上,未来应拓展更多的研究方向,尤其是在开发利用中的“变害为宝”方面应加大研究力度。展开更多
基金Department of Science&Technology,New Delhi(DST-SERB/CRG/2019/004139)for providing financial support。
文摘Invasive plant Ageratina adenophora(Sprengel)R.King&H.Robinson has invaded majority of the temperate forests in Kumaun,Central Himalaya.Information on A.adenophora invaded forest types,their structural attributes,population demography and regeneration status are still at rudimentary level.Considering this,the present study was conducted to assess the impacts of A.adenophora on vegetational attributes and regeneration status of three forest types,viz.,Oak(Quercus oblongata D.Don),Pine(Pinus roxburghii Sarg.)and Cypress(Cupressus torulosa D.Don).We selected three sites for each forest type and each site was further purposively stratified into paired sampling plots of 1 ha each i.e.,A.adenophora invaded and uninvaded sites.Our results showed large densities of cut stumps or felled trees throughout invaded sites,but with fewer fire signs in comparison to uninvaded sites.In uninvaded sites,total density and basal area calculated for woody species were relatively higher than those in invaded sites,although results were insignificant(p>0.05).With the exception for Cypress forests,vegetation indices showed low woody species richness and diversity in invaded Oak and Pine forests.Also,regeneration of Q.oblongata,P.roxburghii and C.torulosa tree species did not differ significantly(p>0.05)between invaded and uninvaded sites.These insignificant differences clearly imply that A.adenophora's presence has not entirely changed the perennial plant communities in terms of composition,structure and natural regeneration.However,tree species with poor or no regeneration status requires special attention and needs management strategies involving control of invasive species in forest ecosystems.
基金the National Natural Science Foundations of China(31772229 and 31660546)。
文摘Rhizosphere microbial communities play important roles in facilitating or inhibiting the establishment of exotic species.Since some invasive plants interact with soil microbial communities such as rhizosphere bacteria,changes triggered by rhizosphere bacteria may alter competitive interactions between exotic and native plants.This study compared the Bacillus cereus content in soils with different degrees of Ageratina adenophora invasion,and investigated the effects of A.adenophora allelochemicals on B.cereus growth and soil characteristics and the feedback effects of B.cereus on A.adenophora growth.Bacillus cereus content in the rhizosphere of A.adenophora increased with intensification of the invasion process,and newly invaded soil contained almost twice as much bacteria as noninvaded soil.When rhizosphere soil was added to the root exudates of A.adenophora,the contents of B.cereus were twice as much as the control,except on the first day.Certain soil parameters increased significantly,such as ammonium nitrogen(NH_(4)^(+)-N)and available phosphorus(AP),which were increased by 41 and 27%,respectively.Soil treatment with B.cereus promoted the degradation of two allelochemicals from the rhizosphere of A.adenophora,amorpha-4,7(11)-dien-8-one and 6-hydroxy-5-isopropy1-3,8-dimethyl-4 a,5,6,7,8,8 ahexahydraphthalen-2(1 H)-one,to varying degrees;and increased the germination rate by 50%,root length by 117%,shoot length by 48%and fresh weight by 81%for A.adenophora compared to those of untreated soil.Our results confirmed that the invasion of A.adenophora will promote an increase of B.cereus,a beneficial rhizosphere bacterium,which in turn induces a positive feedback effect on A.adenophora.
基金the Project of the Chinese Academy of Sciences (KSCX1-SW-13, KSCX2-YW-N-52)Project of the Ministry of Science and Technologyof China (2005DKA21006).
文摘Allelopathy of Ageratina adenophora plays an important role in its invasion. However, we have little knowledge of its allelpathic effects on ferns. In Petri dish bioassays, the inhibitory potential of aqueous leachates from roots, stems and leaves of A. adenophora was studied on the spore germination and gametophyte development of Macrothelypteris torresiana. All leachatss inhibited the spore germination and growth of the first rhizoid of M. torresiana and inhibitory effects increased with increasing leachate concentrations. Root leachates proved most inhibitory. Gametophyte rhizoids of M. torresiana treated with stem and leaf leachates of A. adenophora were erect, which was similar to those of the control. However, gametophyte rhizoids of M. torresiana treated with root leachates of A. adenophora were erect, but also curving or swollen. Moreover, curving and swollen rhizoids increased with increasing concentrations. As time went by, rhizoids treated with root leachates were not so curved and the swelling almost disappeared. Possible causes are discussed in the present study. The increasing concentrations of leaf leachates also delayed the stages of gametophyte development. With the treatment of root leachates, the delay was more obvious. Thus A. adenophora inhibited the spore germination and gametophyte development of M. torresiana and the root leachates were most inhibitory.
基金supported by Yunnan Fundamental Research Projects(202101AU070150)the National Natural Science Foundation of China(31870524,32071663,32071661).
文摘Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investigate the soil chemical and microbiological properties along an altitudinal gradient on a mountain colonized by the invader Ageratina adenophora.Rhizosphere soil of A.adenophora was collected over an altitudinal gradient(1400–2400 m)in Ailao Shan,China.We determined soil organic carbon(C),nutrient contents,enzyme activities,bacterial community composition as well as C and nitrogen(N)contents of the plant roots.Ecoenzymatic stoichiometric indices were calculated to estimate the relative C,N or P limitations of the microbial community.There was a significant effect of altitude on soil organic C in the rhizosphere,and a turning point in these measured variables was detected at an altitude of 2000 m.At low elevations,the rapid growth of invasive plants depleted the deficient phosphorus(P)in tropical soils,leading to microbial P limitation;at high elevations,microbes invested more energy to obtain C from resistant litter,leading to microbial C limitation.Bacterial beta diversity and soil pH contributed most to the altitudinal differences in ecoenzymatic stoichiometry,and Proteobacteria and Acidobacteria were the dominant bacterial phyla that determined the nutrient uptake status of microorganisms.These results demonstrate how microbial nutrient acquisition belowground of A.adenophora along an altitudinal gradient,which could contribute to further knowledge about the effects of altitude on biological invasion.
基金The National Natural Science Foundation of China(No.U1133605)Natural Science Foundation of Yunnan Province(No.2006C0056M)Project of‘Hundred Talents Program of Chinese Academy of Science’(No.BRJH2002098).
文摘Aims Crofton weed,with a subtropical origin,has successfully invaded in diverse habitats that belong to different climate zones in southwest China.We tested whether local adaptation plays an important role in the successful invasion of crofton weed in heterogeneous environments.Methods Five populations from different habitats with an altitude ranging from 678 to 2356 m were selected.Plant height,biomass,seed yield and seed germination capability of these populations were investigated in the field.greenhouse and reciprocal transplant experiments with the five populations were conducted,and all the above characters were measured and compared among these populations.Important Findings Plant height,biomass,seed yield and seed germination rate were each significantly different among the five populations in field.However,there was no difference among these populations in the greenhouse experiment.In the reciprocal transplant experiment,plants from the five populations responded similarly to different habitats in the field,indicat-ing lack of local adaptation.Instead,phenotypic plasticity likely plays a key role in the invasion success of crofton weed in different habitats.
基金supported by the National Basic Research Program of China (Grant Nos.2009CB119200 and 2002CB111400)the National Natural Science Foundation of China (Grant No.30871654)
文摘In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation,the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion,interaction and competition between inter-and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.
文摘紫茎泽兰(Ageratina adenophora)是多年生草本植物,主要分布于热带与温带,是入侵植物中危害最严重的物种之一。基于中国知网和Web of Science核心库集,对已发表的紫茎泽兰相关文献进行计量分析,旨在了解国内外对该植物防治、利用以及研究的现状和发展趋势,明确研究前沿与热点问题,为进一步开展紫茎泽兰相关研究提供参考。结果表明,紫茎泽兰是国内外生态与环境保护领域重点研究的入侵物种。我国科研工作者在其防控、利用研究中发挥着重大作用,但科研机构、研究人员间的交流与合作有待加强,同时学科交叉发展不足。近年来该领域的研究热点主要集中于探究紫茎泽兰的性能及其开发利用上,未来应拓展更多的研究方向,尤其是在开发利用中的“变害为宝”方面应加大研究力度。