Heavy metal contamination to the environment is a serious problem in the developing countries due to anthropogenic activities, a threat needs to remediate to sustain the life on earth, technology includes use of micro...Heavy metal contamination to the environment is a serious problem in the developing countries due to anthropogenic activities, a threat needs to remediate to sustain the life on earth, technology includes use of microorganisms and different plant species. In consideration of biomass, phytoremediation is a very useful techniques above all, can be exploit by identification of hyperaccumulator, which accumulates the heavy metal under metal stress condition. In view of constraints of efficient plant species in present study thirty seven different plant species were screened for the identification of heavy metal accumulators. Croton bonplandianum, sedges and Balanites aegyptiaca amongst the all exhibit superior potential of heavy metal accumulation. This is the first report to unravel the heavy metal accumulation property of three different plant species which can be exploited for the bioremediation of heavy metals.展开更多
Wet sedge meadows are the most productive plant communities in the High Arctic.However,the controls on carbon dioxide(CO_(2))exchange processes within wet sedge communities-and the scale at which they operate-are poor...Wet sedge meadows are the most productive plant communities in the High Arctic.However,the controls on carbon dioxide(CO_(2))exchange processes within wet sedge communities-and the scale at which they operate-are poorly understood.Here,the factors controlling CO_(2)exchange of wet sedge meadows experiencing different moisture regimes are examined.Environmental data are used to create predictive models of CO_(2)exchange on multiple temporal scales.Automated chamber systems recorded CO_(2)fluxes at 30-minute intervals at wet sedge sites in the Canadian High Arctic from June to August in 2014 and 2015.Static chambers were also deployed over a larger spatial extent in 2014.Our results show that wet sedge communities were strong CO_(2)sinks during the growing season(−7.67 to−44.36 g C·m^(−2)).CO_(2)exchange rates in wetter and drier areas within wet sedge meadows differed significantly(Wilcoxon,p<0.001),suggesting that soil moisture regimes within vegetation types influence net CO_(2)balance.Random Forest models explained a significant amount of the variability in CO_(2)flux rates over time(R2=0.46 to 0.90).The models showed that the drivers of CO_(2)exchange in these communities vary temporally.Variable moisture regimes indirectly influenced CO_(2)fluxes given that they exhibit different vegetation and temperature-response characteristics.We suggest that the response of a single vegetation type to environmental changes may vary depending on microenvironment variability within that community.展开更多
Water level fluctuations (WLF) are natural patterns that are necessary for the survival of various plants,and WLF guarantee both the productivity and the biodiversity of wetlands.However,the underlying mechanisms of h...Water level fluctuations (WLF) are natural patterns that are necessary for the survival of various plants,and WLF guarantee both the productivity and the biodiversity of wetlands.However,the underlying mechanisms of how changes in vegetation are linked to seasonal WLF remain unclear.Using vegetation and hydrological data from 1989 to 2009,we identified the key seasonal fluctuations and their impacts on vegetation in the Poyang Lake wetland by utilizing a tree-based hierarchical model.According to our results: 1) WLF in summer had significant impacts on both sedges and reeds.The severe summer floods promoted the expansion of sedges,while they inhibited the expansion of reeds;2) WLF in autumn also greatly impacted sedges,while reeds were severely affected in spring.Specifically,we found that low water levels in autumn led to the expansion of sedges,and low water levels in spring led to the expansion of reeds.The results were well corroborated through comparisons of the vegetation distribution patterns over the last two decades (i.e.,the 1990s and 2000s),which may shed light on corresponding water resource and wetland management.展开更多
文摘Heavy metal contamination to the environment is a serious problem in the developing countries due to anthropogenic activities, a threat needs to remediate to sustain the life on earth, technology includes use of microorganisms and different plant species. In consideration of biomass, phytoremediation is a very useful techniques above all, can be exploit by identification of hyperaccumulator, which accumulates the heavy metal under metal stress condition. In view of constraints of efficient plant species in present study thirty seven different plant species were screened for the identification of heavy metal accumulators. Croton bonplandianum, sedges and Balanites aegyptiaca amongst the all exhibit superior potential of heavy metal accumulation. This is the first report to unravel the heavy metal accumulation property of three different plant species which can be exploited for the bioremediation of heavy metals.
基金ArcticNet NCE,the Natural Sciences and Engineering Research Council,Natural Resources Canada(Polar Continental Shelf Program)the Northern Scientific Training Program,and Queen’s University。
文摘Wet sedge meadows are the most productive plant communities in the High Arctic.However,the controls on carbon dioxide(CO_(2))exchange processes within wet sedge communities-and the scale at which they operate-are poorly understood.Here,the factors controlling CO_(2)exchange of wet sedge meadows experiencing different moisture regimes are examined.Environmental data are used to create predictive models of CO_(2)exchange on multiple temporal scales.Automated chamber systems recorded CO_(2)fluxes at 30-minute intervals at wet sedge sites in the Canadian High Arctic from June to August in 2014 and 2015.Static chambers were also deployed over a larger spatial extent in 2014.Our results show that wet sedge communities were strong CO_(2)sinks during the growing season(−7.67 to−44.36 g C·m^(−2)).CO_(2)exchange rates in wetter and drier areas within wet sedge meadows differed significantly(Wilcoxon,p<0.001),suggesting that soil moisture regimes within vegetation types influence net CO_(2)balance.Random Forest models explained a significant amount of the variability in CO_(2)flux rates over time(R2=0.46 to 0.90).The models showed that the drivers of CO_(2)exchange in these communities vary temporally.Variable moisture regimes indirectly influenced CO_(2)fluxes given that they exhibit different vegetation and temperature-response characteristics.We suggest that the response of a single vegetation type to environmental changes may vary depending on microenvironment variability within that community.
基金the National Key Research and Development Project of China (No.2016YFC0402204)the National Natural Science Foundation of China (Grant No.41571107)+1 种基金the Key Research Program of the Chinese Academy of Sciences (No.KFZD-SW-318)the Key Project of Water Resources Department of Jiangxi Province (No.KT201503).
文摘Water level fluctuations (WLF) are natural patterns that are necessary for the survival of various plants,and WLF guarantee both the productivity and the biodiversity of wetlands.However,the underlying mechanisms of how changes in vegetation are linked to seasonal WLF remain unclear.Using vegetation and hydrological data from 1989 to 2009,we identified the key seasonal fluctuations and their impacts on vegetation in the Poyang Lake wetland by utilizing a tree-based hierarchical model.According to our results: 1) WLF in summer had significant impacts on both sedges and reeds.The severe summer floods promoted the expansion of sedges,while they inhibited the expansion of reeds;2) WLF in autumn also greatly impacted sedges,while reeds were severely affected in spring.Specifically,we found that low water levels in autumn led to the expansion of sedges,and low water levels in spring led to the expansion of reeds.The results were well corroborated through comparisons of the vegetation distribution patterns over the last two decades (i.e.,the 1990s and 2000s),which may shed light on corresponding water resource and wetland management.