Aims Invasive species occurrence and their effects on biodiversity may vary along latitudes.We examined the occurrence(species cover)and relative dominance(importance value)of invasive alligator weed,Alternanthera phi...Aims Invasive species occurrence and their effects on biodiversity may vary along latitudes.We examined the occurrence(species cover)and relative dominance(importance value)of invasive alligator weed,Alternanthera philoxeroides,in its terrestrial habitat in China through a large-scale latitudinal field investigation.Methods We established 59 plots along the latitudinal transect from 21°N to 37°N.We recorded species name,abundance,height and individual species coverage of plants in every quadrat.We then measuredα-species diversity variations associated with the A.philoxeroides community across the latitudinal range.We also analyzed the effect of latitude on plant species’distributions in this community by using canonical correspondence analysis(CCA).Important Findings We found that species cover and importance value of A.philoxe-roides increased in areas<35°N,but decreased at higher latitudes.Lower latitudes supported greater species diversity than higher latitudes.Small-scale invasion of A.philoxeroides was associated with higher species diversity,but community diversity was lower when A.philoxeroides species cover exceeded 36%.Community plant species changed from mesophyte to hygrophyte gradually from low to high latitude.Our research suggests that latitude had significant influences on community diversity which interacted with the biotic resistance of a community and impact of invasion.Consequently,A.philoxeroides may become more invasive and have greater negative impacts on community species diversity in higher latitudes as global climate changes.展开更多
Aims Clonal integration,i.e.resource sharing between interconnected ramets,can help clonal plants tolerate abiotic stress.However,few studies have directly examined the ecological significance of clonal integration in...Aims Clonal integration,i.e.resource sharing between interconnected ramets,can help clonal plants tolerate abiotic stress.However,few studies have directly examined the ecological significance of clonal integration in the ability of clonal plants to tolerate biotic stress such as herbivory.Methods We grew clonal fragments of an invasive clonal plant Alternanthera philoxeroides,each consisting of an apical part(relatively young)and a basal part(relatively old),at two levels(low and high)of soil nitrogen(N).For each fragment,the apical part was subjected to either no herbivory or herbivory for 2 weeks by a specialist insect,Agasicles hygrophila,and was either connected with or discon-nected from the basal part not subjected to herbivory.Important Findings Herbivory in the apical part severely reduced leaf growth(leaf mass,leaf number or leaf area)and ramet production of both apical and basal parts,and increased root to shoot ratio of the apical part.Irrespective of herbivory and soil N,stem connection between the apical and the basal part decreased root to shoot ratio of the ap-ical part,but did not change its growth measures.Meanwhile,con-nection increased stem N concentration of the apical part growing under high-N supply and decreased stem carbon(C)concentration of the apical part under low-N supply.By contrast,connection in-creased root to shoot ratio of the basal part,but reduced its leaf and ramet production.Connection also increased leaf and stem C concentrations of the basal part under low-N supply.Thus,clonal integration can be beneficial for the early development of young A.philoxeroides ramets,but not for their local adaptation to herbivory damage by A.hygrophila.展开更多
Plants growing in nutrient-rich environment are predicted to be less defended than conspecifics under nutrient limitation.However,less is known about the effects of nutrient levels on tolerance and induced resistance,...Plants growing in nutrient-rich environment are predicted to be less defended than conspecifics under nutrient limitation.However,less is known about the effects of nutrient levels on tolerance and induced resistance,and whether the effects differ between native and introduced populations of invasive plants.We performed a greenhouse experiment with introduced(the USA)and native(Argentina)genotypes of Alternanthera philoxeroides in order to study the effects of soil nitrogen levels on plant growth,constitutive and herbivore(Agasicles hygrophila)-induced chemical defense,and herbivory tolerance.We measured total biomass,elongation rate(as proxy of growth rate),carbon and nitrogen,and the concentration of triterpenoid saponins(defensive chemicals)in leaves and roots.Constitutive resistance(+33%higher leaf triterpenoid saponins in control treatment at low nitrogen level)and tolerance[less decreased total biomass after herbivory treatment(−24%and−15%for high and low nitrogen levels)]were favored at lower nitrogen level,while induced resistance was favored at higher nitrogen level(+24%increased leaf triterpenoid saponins after herbivory treatment at high nitrogen level).Constitutive resistance and tolerance exhibited trade-offs with growth rate,while induced resistance positively correlated with growth rate.Additionally,the introduced genotypes had−6%lower content of leaf carbon in the presence of herbivores than the native genotypes at low nitrogen level,but such difference was absent at high nitrogen level.Our results indicate that soil nitrogen levels influence the preference of different defensive strategies of plant,and interweave with herbivory to determine the performance of introduced genotypes.展开更多
A greenhouse experiment was conducted to determine the influence of the environmental factors such as low-temperature, drought stress, salt-alkali and flooding on the survival rate, propagation rate, fresh biomass and...A greenhouse experiment was conducted to determine the influence of the environmental factors such as low-temperature, drought stress, salt-alkali and flooding on the survival rate, propagation rate, fresh biomass and viability of the Altemanthera philoxeroides and its competitive ability against rice by using bioassay method. A high viability of 84% was found when the stems were treated at 4℃ and then grew under normal conditions, while no viable plant was noted when the stems were treated at -20℃ and grew under normal conditions. Compared to the fresh stem with water content of 93.5%, the survival rate, number of propagated stems and fresh biomass of A. philoxeroides derived from the stems with water content of 30.2% were reduced by 45%, 33% and 74% respectively. The treatments of 0.1% salt-alkaline solution led to loss of viability of A, philoxeroides. The stems of A. philoxeroides could grow in wet soil with different depths of water-layer. The A. philoxeroides at density of 23-180 plants/m^2 reduced the rice grain yield by 43-50% at the rice plant density of 100 plants/m^2.展开更多
设计对照组(120 m L接种物)和试验组(120 m L接种物+71 g空心莲子草),采用全混合批量式发酵模式,在中温30℃的条件下,进行沼气发酵试验,研究空心莲子草(Alternanthera philoxeroides Griseb.)的产沼气潜力。结果表明,试验组的沼气发酵历...设计对照组(120 m L接种物)和试验组(120 m L接种物+71 g空心莲子草),采用全混合批量式发酵模式,在中温30℃的条件下,进行沼气发酵试验,研究空心莲子草(Alternanthera philoxeroides Griseb.)的产沼气潜力。结果表明,试验组的沼气发酵历时27 d,净产气量为3 080 m L。由试验结果计算得出,空心莲子草的TS产气潜力为319 m L/g,VS产气潜力为403 m L/g。展开更多
This study evaluated the physiological characteristics(e.g.,growth parameters,chlorophyll content,metabolites and antioxidative enzymes activity)of Alternanthera philoxeroides(A.philoxeroides),as a hyperaccumulator pl...This study evaluated the physiological characteristics(e.g.,growth parameters,chlorophyll content,metabolites and antioxidative enzymes activity)of Alternanthera philoxeroides(A.philoxeroides),as a hyperaccumulator plant,during the phytoremediation of cadmium(Cd)from water.After cultivating A.philoxeroides in a Cd-containing medium for 30 days,the growth rate was inhibited by up to 33.5%as the exposed Cd concentration increased to 0.80 mmol·L−1.Cd exposure interfered with the photosynthesis of A.philoxeroides and caused oxidative stress as indicated by the rise of malondialdehyde(MDA)and H2O2,which increased by 8 times and 3 times compared to the control group.Moreover,high exposure concentrations of Cd also reduced the activities of multiple antioxidants(e.g.,GSH and AsA),indicating the inhibition of Cd on the plant’s ability to mitigate oxidative damage.Finally,the fluorescent patterns of the rhizosphere dissolved organic matter(rDOM)revealed three major components(humic,fulvic substances and protein-like substances)well correlated with the changes in antioxidant activities.Partial least-squares discriminant analysis(PLS-DA)visualized the difference in the activity of the antioxidative enzymes between different groups.The study unravelled deep insights into the potential mechanisms of tolerance and resistance of A.philoxeroides for phytoremediation of Cd pollution.展开更多
基金Knowledge Innovation Program of Wuhan Botanical Garden(Y455437H05)supported by a National Science Foundation Postdoctoral Research Fellowship.
文摘Aims Invasive species occurrence and their effects on biodiversity may vary along latitudes.We examined the occurrence(species cover)and relative dominance(importance value)of invasive alligator weed,Alternanthera philoxeroides,in its terrestrial habitat in China through a large-scale latitudinal field investigation.Methods We established 59 plots along the latitudinal transect from 21°N to 37°N.We recorded species name,abundance,height and individual species coverage of plants in every quadrat.We then measuredα-species diversity variations associated with the A.philoxeroides community across the latitudinal range.We also analyzed the effect of latitude on plant species’distributions in this community by using canonical correspondence analysis(CCA).Important Findings We found that species cover and importance value of A.philoxe-roides increased in areas<35°N,but decreased at higher latitudes.Lower latitudes supported greater species diversity than higher latitudes.Small-scale invasion of A.philoxeroides was associated with higher species diversity,but community diversity was lower when A.philoxeroides species cover exceeded 36%.Community plant species changed from mesophyte to hygrophyte gradually from low to high latitude.Our research suggests that latitude had significant influences on community diversity which interacted with the biotic resistance of a community and impact of invasion.Consequently,A.philoxeroides may become more invasive and have greater negative impacts on community species diversity in higher latitudes as global climate changes.
基金This work was supported by National Key Research and Development Program of China(2016YFC1201101,2016YFC1202102)the National Natural Science Foundation of China(31500331,31670428)+1 种基金the Fundamental Research Funds for the Central Universities(2015ZCQ-BH-01)Undergraduate Innovation and Entrepreneurship Training Program of Beijing Forestry University(X201710022152).
文摘Aims Clonal integration,i.e.resource sharing between interconnected ramets,can help clonal plants tolerate abiotic stress.However,few studies have directly examined the ecological significance of clonal integration in the ability of clonal plants to tolerate biotic stress such as herbivory.Methods We grew clonal fragments of an invasive clonal plant Alternanthera philoxeroides,each consisting of an apical part(relatively young)and a basal part(relatively old),at two levels(low and high)of soil nitrogen(N).For each fragment,the apical part was subjected to either no herbivory or herbivory for 2 weeks by a specialist insect,Agasicles hygrophila,and was either connected with or discon-nected from the basal part not subjected to herbivory.Important Findings Herbivory in the apical part severely reduced leaf growth(leaf mass,leaf number or leaf area)and ramet production of both apical and basal parts,and increased root to shoot ratio of the apical part.Irrespective of herbivory and soil N,stem connection between the apical and the basal part decreased root to shoot ratio of the ap-ical part,but did not change its growth measures.Meanwhile,con-nection increased stem N concentration of the apical part growing under high-N supply and decreased stem carbon(C)concentration of the apical part under low-N supply.By contrast,connection in-creased root to shoot ratio of the basal part,but reduced its leaf and ramet production.Connection also increased leaf and stem C concentrations of the basal part under low-N supply.Thus,clonal integration can be beneficial for the early development of young A.philoxeroides ramets,but not for their local adaptation to herbivory damage by A.hygrophila.
基金supported by the National Natural Science Foundation of China(grant no.41771053,32071659,31961133028 and 32030067).
文摘Plants growing in nutrient-rich environment are predicted to be less defended than conspecifics under nutrient limitation.However,less is known about the effects of nutrient levels on tolerance and induced resistance,and whether the effects differ between native and introduced populations of invasive plants.We performed a greenhouse experiment with introduced(the USA)and native(Argentina)genotypes of Alternanthera philoxeroides in order to study the effects of soil nitrogen levels on plant growth,constitutive and herbivore(Agasicles hygrophila)-induced chemical defense,and herbivory tolerance.We measured total biomass,elongation rate(as proxy of growth rate),carbon and nitrogen,and the concentration of triterpenoid saponins(defensive chemicals)in leaves and roots.Constitutive resistance(+33%higher leaf triterpenoid saponins in control treatment at low nitrogen level)and tolerance[less decreased total biomass after herbivory treatment(−24%and−15%for high and low nitrogen levels)]were favored at lower nitrogen level,while induced resistance was favored at higher nitrogen level(+24%increased leaf triterpenoid saponins after herbivory treatment at high nitrogen level).Constitutive resistance and tolerance exhibited trade-offs with growth rate,while induced resistance positively correlated with growth rate.Additionally,the introduced genotypes had−6%lower content of leaf carbon in the presence of herbivores than the native genotypes at low nitrogen level,but such difference was absent at high nitrogen level.Our results indicate that soil nitrogen levels influence the preference of different defensive strategies of plant,and interweave with herbivory to determine the performance of introduced genotypes.
基金This paper was translated from its Chinese version in Chinese Journal of Rice Science.
文摘A greenhouse experiment was conducted to determine the influence of the environmental factors such as low-temperature, drought stress, salt-alkali and flooding on the survival rate, propagation rate, fresh biomass and viability of the Altemanthera philoxeroides and its competitive ability against rice by using bioassay method. A high viability of 84% was found when the stems were treated at 4℃ and then grew under normal conditions, while no viable plant was noted when the stems were treated at -20℃ and grew under normal conditions. Compared to the fresh stem with water content of 93.5%, the survival rate, number of propagated stems and fresh biomass of A. philoxeroides derived from the stems with water content of 30.2% were reduced by 45%, 33% and 74% respectively. The treatments of 0.1% salt-alkaline solution led to loss of viability of A, philoxeroides. The stems of A. philoxeroides could grow in wet soil with different depths of water-layer. The A. philoxeroides at density of 23-180 plants/m^2 reduced the rice grain yield by 43-50% at the rice plant density of 100 plants/m^2.
文摘设计对照组(120 m L接种物)和试验组(120 m L接种物+71 g空心莲子草),采用全混合批量式发酵模式,在中温30℃的条件下,进行沼气发酵试验,研究空心莲子草(Alternanthera philoxeroides Griseb.)的产沼气潜力。结果表明,试验组的沼气发酵历时27 d,净产气量为3 080 m L。由试验结果计算得出,空心莲子草的TS产气潜力为319 m L/g,VS产气潜力为403 m L/g。
基金supported by National Natural Science Foundation of China(52070122,42007176)Taishan Scholar Foundation,Natural Science Foundation of Shandong Province(ZR2020QD125,ZR2020ME222)+1 种基金Key Scientific and Technological Innovation Foundation of Shandong Province(No.2020CXGC011404)the program of 20 Policies for University in Jinan(202228056).
文摘This study evaluated the physiological characteristics(e.g.,growth parameters,chlorophyll content,metabolites and antioxidative enzymes activity)of Alternanthera philoxeroides(A.philoxeroides),as a hyperaccumulator plant,during the phytoremediation of cadmium(Cd)from water.After cultivating A.philoxeroides in a Cd-containing medium for 30 days,the growth rate was inhibited by up to 33.5%as the exposed Cd concentration increased to 0.80 mmol·L−1.Cd exposure interfered with the photosynthesis of A.philoxeroides and caused oxidative stress as indicated by the rise of malondialdehyde(MDA)and H2O2,which increased by 8 times and 3 times compared to the control group.Moreover,high exposure concentrations of Cd also reduced the activities of multiple antioxidants(e.g.,GSH and AsA),indicating the inhibition of Cd on the plant’s ability to mitigate oxidative damage.Finally,the fluorescent patterns of the rhizosphere dissolved organic matter(rDOM)revealed three major components(humic,fulvic substances and protein-like substances)well correlated with the changes in antioxidant activities.Partial least-squares discriminant analysis(PLS-DA)visualized the difference in the activity of the antioxidative enzymes between different groups.The study unravelled deep insights into the potential mechanisms of tolerance and resistance of A.philoxeroides for phytoremediation of Cd pollution.
