A survey of 35 tree species （belonging to 28 genera in 19 families） in Aliyar, South India was carried out to ascertain their arbuscular mycorrhizal （AM） and dark septate endophyte （DSE） fungal status. All the t...A survey of 35 tree species （belonging to 28 genera in 19 families） in Aliyar, South India was carried out to ascertain their arbuscular mycorrhizal （AM） and dark septate endophyte （DSE） fungal status. All the tree species examined had AM association. AM and DSE coloni- zation is reported for the first time in 20 and 14 species respectively. Co- occurrence of AM and DSE was observed in 14 （40%） tree species. The extent of DSE colonization was inversely related to the extent of AM fungal colonization. Six tree species had Arum-type, 18 had intermediate- type and 11 had typical Paris-type AM morphology. AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil. AM fungal spore numbers were not related to the ex- tent of AM colonization and Glomus dominated spore diversity. AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species. The occur- rence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this asso- ciation in future conservation programmes of these species.展开更多
Ammonia(NH_(3))synthesis at mild conditions is of great significance,while the significant bottleneck of this process is the activation of N_(2) to realize the desired NH_(3) synthesis performance,which requires deep ...Ammonia(NH_(3))synthesis at mild conditions is of great significance,while the significant bottleneck of this process is the activation of N_(2) to realize the desired NH_(3) synthesis performance,which requires deep insight and rational design of active sites at the atomic level.Here,were synthesized atomically dispersed Co-based catalysts with different Co-N coordination numbers(CNs)to explore the coordination-sensitive NH_(3) synthesis reaction for the first time.Our studies showed that Co-based catalysts increased the NH_(3) synthesis rate gradually with a decrease in CN.The Co-N_(2) catalyst exhibited the highest NH_(3) synthesis rate of 85.3 mmol gCo^(−1) h^(−1) at 300℃ and 1 MPa,which outperformed most of the previously reported Co-based catalysts.Various characterizations and theoretical calculations demonstrated that atomically dispersed Co catalyst with low CN could generate more unoccupied Co 3d charges and tetrahedral cobalt(Ⅱ)sites.The unoccupied Co 3d charge,in turn,promoted the electron donation from the Co active center to the antibonding π-orbital(π*)of N_(2) and expedites N_(2) hydrogenation.Furthermore,the Co-N_(2) catalyst with more tetrahedral cobalt(II)sites could effectively facilitate the desorption of N-containing intermediate species(such as*NH_(3) and*N_(2)H_(4))to obtain a high NH_(3) synthesis rate.展开更多
Conversion of natural environments to human-modified landscapes is continuing at an unprecedented rate,exerting fundamental influences on global biodiversity.Understanding how wildlife communities respond to landscape...Conversion of natural environments to human-modified landscapes is continuing at an unprecedented rate,exerting fundamental influences on global biodiversity.Understanding how wildlife communities respond to landscape modifications is critical to improve biodiversity conservation in human-dominated landscapes.In this study,we surveyed bird communities in three common habitats(i.e.,farmland,village,and forest)in the southern Anhui Mountainous Area during summer(August 2019)and winter(December 2020).The diversity metrics and species compositions of the avian communities were compared among the habitats,and the effects of land use composition in these habitats were tested.During the field surveys,we recorded 7599 birds of 120 species along 45 line transects of 1km in length.The land use compositions differed among habitats,and land use diversity was the highest in villages and lowest in forests.The species richness and bird abundance in the two human-dominated habitats(i.e.,farmland and village)were higher than those in forest in both seasons.Bird species composition also differed across habitat types in both seasons.Bird species feeding on vertebrates,fish and carrion,and species feeding on plants and seeds were mainly found in habitats with less construction lands and lower land use diversity,while omnivorous species and species feeding on fruits and nectar or on invertebrates were less affected by these two variables.The indicator species analysis showed that most species associated with forest feed on invertebrates,while species feeding on plants and seeds were more correlated with farmland and village.The results indicated that the conversion of natural habitats to human-dominated landscapes has pronounced impacts on bird communities in the study area.Human-dominated habitats harboured more avian species that deserve conservation attention.Meanwhile,bird conservations should not be relaxed in forests because there were more than 20 species that had a high specificity for forests.展开更多
文摘A survey of 35 tree species （belonging to 28 genera in 19 families） in Aliyar, South India was carried out to ascertain their arbuscular mycorrhizal （AM） and dark septate endophyte （DSE） fungal status. All the tree species examined had AM association. AM and DSE coloni- zation is reported for the first time in 20 and 14 species respectively. Co- occurrence of AM and DSE was observed in 14 （40%） tree species. The extent of DSE colonization was inversely related to the extent of AM fungal colonization. Six tree species had Arum-type, 18 had intermediate- type and 11 had typical Paris-type AM morphology. AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil. AM fungal spore numbers were not related to the ex- tent of AM colonization and Glomus dominated spore diversity. AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species. The occur- rence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this asso- ciation in future conservation programmes of these species.
基金supported by the National Key Natural Science Foundation of China(grant no.22038002)the National Natural Science Foundation of China(grant no.21972019).
文摘Ammonia(NH_(3))synthesis at mild conditions is of great significance,while the significant bottleneck of this process is the activation of N_(2) to realize the desired NH_(3) synthesis performance,which requires deep insight and rational design of active sites at the atomic level.Here,were synthesized atomically dispersed Co-based catalysts with different Co-N coordination numbers(CNs)to explore the coordination-sensitive NH_(3) synthesis reaction for the first time.Our studies showed that Co-based catalysts increased the NH_(3) synthesis rate gradually with a decrease in CN.The Co-N_(2) catalyst exhibited the highest NH_(3) synthesis rate of 85.3 mmol gCo^(−1) h^(−1) at 300℃ and 1 MPa,which outperformed most of the previously reported Co-based catalysts.Various characterizations and theoretical calculations demonstrated that atomically dispersed Co catalyst with low CN could generate more unoccupied Co 3d charges and tetrahedral cobalt(Ⅱ)sites.The unoccupied Co 3d charge,in turn,promoted the electron donation from the Co active center to the antibonding π-orbital(π*)of N_(2) and expedites N_(2) hydrogenation.Furthermore,the Co-N_(2) catalyst with more tetrahedral cobalt(II)sites could effectively facilitate the desorption of N-containing intermediate species(such as*NH_(3) and*N_(2)H_(4))to obtain a high NH_(3) synthesis rate.
基金supported by the National Natural Science Foundation of China (grant numbers 31970500 and 31770571)the Excellent Youth Project of the Anhui Natural Science Foundation (2108085Y09)the Biodiversity Investigation,Observation and Assessment Program (2019-2023) of Ministry of Ecology and Environment of China
文摘Conversion of natural environments to human-modified landscapes is continuing at an unprecedented rate,exerting fundamental influences on global biodiversity.Understanding how wildlife communities respond to landscape modifications is critical to improve biodiversity conservation in human-dominated landscapes.In this study,we surveyed bird communities in three common habitats(i.e.,farmland,village,and forest)in the southern Anhui Mountainous Area during summer(August 2019)and winter(December 2020).The diversity metrics and species compositions of the avian communities were compared among the habitats,and the effects of land use composition in these habitats were tested.During the field surveys,we recorded 7599 birds of 120 species along 45 line transects of 1km in length.The land use compositions differed among habitats,and land use diversity was the highest in villages and lowest in forests.The species richness and bird abundance in the two human-dominated habitats(i.e.,farmland and village)were higher than those in forest in both seasons.Bird species composition also differed across habitat types in both seasons.Bird species feeding on vertebrates,fish and carrion,and species feeding on plants and seeds were mainly found in habitats with less construction lands and lower land use diversity,while omnivorous species and species feeding on fruits and nectar or on invertebrates were less affected by these two variables.The indicator species analysis showed that most species associated with forest feed on invertebrates,while species feeding on plants and seeds were more correlated with farmland and village.The results indicated that the conversion of natural habitats to human-dominated landscapes has pronounced impacts on bird communities in the study area.Human-dominated habitats harboured more avian species that deserve conservation attention.Meanwhile,bird conservations should not be relaxed in forests because there were more than 20 species that had a high specificity for forests.
