The interactive eff ects of ozone,soil nutrient availability and root microorganisms on physiological,growth,and productivity traits were studied for the fi rst time for Japanese larch(Larix kaempferi)seedlings grown ...The interactive eff ects of ozone,soil nutrient availability and root microorganisms on physiological,growth,and productivity traits were studied for the fi rst time for Japanese larch(Larix kaempferi)seedlings grown in containers over a growing season,using a free air ozoneconcentration enrichment exposure system.High nutrient availability altered leaf and root nutrient dynamics and enhanced plant growth;however,it also enhanced seedling susceptibility to damping-off disease compared to low nutrient availability.Negative eff ects of elevated ozone,as compared with ambient ozone,on leaf gas exchange and plant stem form were neither off set nor exacerbated by soil nutrient availability and root colonizers.Such negative eff ects suggest that elevated ozone may have implications for ecological health even when plant vigor is limited by factors other than ozone.Inoculation of roots with ectomycorrhizae had negligible infl uence on the eff ects of either soil nutrient availability or ozone.However,this lack of eff ect may be upon impeded formation of complete mycorrhizal root tips due to factors other than the manipulated variables.B and Na appeared to have an important role in stress responses,so further studies to examine their link with physiological mechanisms as a function of time.This study provides an important perspective for designing forestry practices to enhance seedling health.展开更多
The role of N2 fixation in structuring plant communities and influencing ecosystem function will be potentially large. In previous study, we investigated nodule biomass and activity, and calculated the amount of N2 fi...The role of N2 fixation in structuring plant communities and influencing ecosystem function will be potentially large. In previous study, we investigated nodule biomass and activity, and calculated the amount of N2 fixation in a naturally established 18-year-old alder (Alnus hirsute (Turcz.) var. sibirica) stand following disturbance by road construction in Takayama, central Japan. In this study, to estimate the facilitation effects by alder on the spatial distribution of the regenerated tree species, we examined the distribution pattern of the regenerated tree species in this naturally established 18-year-old alder stand. The distribution pattern of alder and the regenerated woody species was analyzed in terms of spatial point processes and the regenerated species tended to distribute near the alder site. In particular, bird-dispersed tree species (endozoochory species) with relatively high shade tolerance showed a significant attraction to alder. These results suggest that alder will be used as roost trees and play the role of mother trees for these regenerated species at the degraded site. It was also suggested that the endozoochory species, which occupy 13 of 26 regenerated species in this stand, might regenerate faster than other species at this alder stand.展开更多
基金The authors are grateful to Mr.Tatsushiro Ueda of Dalton Co.(Hokkaido Branch,Japan)for managing the O3 FACE system and to Mr.Yamamoto and Mr.Noda of Hokkaido University,Japan,for contributing to the ectomycorrhizae analysis.E.A.acknowledges multiyear support from The Startup Foundation for Introducing Talent of Nanjing University of Information Science&Technology(NUIST),Nanjing,China(Grant No.1411021901008).
文摘The interactive eff ects of ozone,soil nutrient availability and root microorganisms on physiological,growth,and productivity traits were studied for the fi rst time for Japanese larch(Larix kaempferi)seedlings grown in containers over a growing season,using a free air ozoneconcentration enrichment exposure system.High nutrient availability altered leaf and root nutrient dynamics and enhanced plant growth;however,it also enhanced seedling susceptibility to damping-off disease compared to low nutrient availability.Negative eff ects of elevated ozone,as compared with ambient ozone,on leaf gas exchange and plant stem form were neither off set nor exacerbated by soil nutrient availability and root colonizers.Such negative eff ects suggest that elevated ozone may have implications for ecological health even when plant vigor is limited by factors other than ozone.Inoculation of roots with ectomycorrhizae had negligible infl uence on the eff ects of either soil nutrient availability or ozone.However,this lack of eff ect may be upon impeded formation of complete mycorrhizal root tips due to factors other than the manipulated variables.B and Na appeared to have an important role in stress responses,so further studies to examine their link with physiological mechanisms as a function of time.This study provides an important perspective for designing forestry practices to enhance seedling health.
文摘The role of N2 fixation in structuring plant communities and influencing ecosystem function will be potentially large. In previous study, we investigated nodule biomass and activity, and calculated the amount of N2 fixation in a naturally established 18-year-old alder (Alnus hirsute (Turcz.) var. sibirica) stand following disturbance by road construction in Takayama, central Japan. In this study, to estimate the facilitation effects by alder on the spatial distribution of the regenerated tree species, we examined the distribution pattern of the regenerated tree species in this naturally established 18-year-old alder stand. The distribution pattern of alder and the regenerated woody species was analyzed in terms of spatial point processes and the regenerated species tended to distribute near the alder site. In particular, bird-dispersed tree species (endozoochory species) with relatively high shade tolerance showed a significant attraction to alder. These results suggest that alder will be used as roost trees and play the role of mother trees for these regenerated species at the degraded site. It was also suggested that the endozoochory species, which occupy 13 of 26 regenerated species in this stand, might regenerate faster than other species at this alder stand.
