Increasing use of pyrethroid insecticides has resulted in concerns regarding potential effects on human health and ecosystems. Cypermethrin and its metabolite 3-phenoxybenzoic acid(PBA) have exerted adverse biological...Increasing use of pyrethroid insecticides has resulted in concerns regarding potential effects on human health and ecosystems. Cypermethrin and its metabolite 3-phenoxybenzoic acid(PBA) have exerted adverse biological impacts on the environment;therefore,it is critically important to develop different methods to enhance their degradation. In this study,incubation experiments were conducted using samples of an Aquic Inceptisol supplied with nitrogen(N) in the form of NH4NO3 at different levels to investigate the effect of nitrogen on the degradation of cypermethrin and PBA in soil. The results indicated that appropriate N application can promote the degradation of cypermethrin and PBA in soil. The maximum degradation rates were 80.0% for cypermethrin after 14 days of incubation in the treatment with N at a rate of 122.1 kg ha-1 and 41.0% for PBA after 60 days of incubation in the treatment with N at a rate of 182.7 kg ha-1. The corresponding rates in the treatments without nitrogen were 62.7% for cypermethrin and 27.8% for PBA. However,oversupplying N significantly reduced degradation of these compounds. Enhancement of degradation could be explained by the stimulation of microbial activity after the addition of N. In particular,dehydrogenase activities in the soil generally increased with the addition of N,except in the soil where N was applied at the highest level. The lower degradation rate measured in the treatment with an oversupply of N may be attributed to the microbial metabolism shifts induced by high N.展开更多
Aims Although soil environments exist extensive heterogeneity for many plants with a wide range of distribution,researches about effects of soil conditions on plants’tolerance and adaptation are particularly inadequa...Aims Although soil environments exist extensive heterogeneity for many plants with a wide range of distribution,researches about effects of soil conditions on plants’tolerance and adaptation are particularly inadequate.In our study,the aims are to reveal physiological strategies of Populus deltoides against drought stress under different soil conditions and to select the most suitable soil type for P.deltoides plantation.Methods Under controlled conditions,we used P.deltoides as a model species to detect differences in gas exchange rate,antioxidative capacity,nitrogen metabolism and biomass accumulation and partitioning in response to drought stress under three mineral soil types with distinct physicochemical characters,i.e.red soil(RS),yellow soil(YS)and yellow-brown soil(BS).Important Findings Exposure to 25%of field water holding capacity in soil for 3 months had significantly decreased biomass of all organs,photosynthetic rate,enzyme activities related to N assimilation,but increased H2O2,malondialdehyde and content of both NO3−and NH4+,when P.deltoides was planted in both RS and YS.In contrast,under BS,there are slightly negative effects exerted by water deficit on total biomass,gas exchange rate,activities of enzymes related to nitrogen metabolism and membrane damage caused by reactive oxygen species,which can be associated with a consistent increase in superoxide dismutase,peroxidase and catalase,and a higher ratio of root mass to shoot mass.It is concluded that,such higher capacity in tolerance and adaptation against drought stress under BS relative to both RS and YS could be accounted for more sufficient nutrient provision in soil parental materials and better soil aeration conditions which play a vital role in plant acclimation to water shortage.Our study also revealed that,distribution areas of BS might be preferable for cultivation of P.deltoides,when compared with those of RS and YS.展开更多
基金the National Key Basic Research Program of China (No.2002CB410810) and the PPI/PPIC Chinaprogram.
文摘Increasing use of pyrethroid insecticides has resulted in concerns regarding potential effects on human health and ecosystems. Cypermethrin and its metabolite 3-phenoxybenzoic acid(PBA) have exerted adverse biological impacts on the environment;therefore,it is critically important to develop different methods to enhance their degradation. In this study,incubation experiments were conducted using samples of an Aquic Inceptisol supplied with nitrogen(N) in the form of NH4NO3 at different levels to investigate the effect of nitrogen on the degradation of cypermethrin and PBA in soil. The results indicated that appropriate N application can promote the degradation of cypermethrin and PBA in soil. The maximum degradation rates were 80.0% for cypermethrin after 14 days of incubation in the treatment with N at a rate of 122.1 kg ha-1 and 41.0% for PBA after 60 days of incubation in the treatment with N at a rate of 182.7 kg ha-1. The corresponding rates in the treatments without nitrogen were 62.7% for cypermethrin and 27.8% for PBA. However,oversupplying N significantly reduced degradation of these compounds. Enhancement of degradation could be explained by the stimulation of microbial activity after the addition of N. In particular,dehydrogenase activities in the soil generally increased with the addition of N,except in the soil where N was applied at the highest level. The lower degradation rate measured in the treatment with an oversupply of N may be attributed to the microbial metabolism shifts induced by high N.
基金supported by Sichuan Science and Technology Program(no.2016NYZ0035-07,2019YJ0416 and 2019YJ0427).
文摘Aims Although soil environments exist extensive heterogeneity for many plants with a wide range of distribution,researches about effects of soil conditions on plants’tolerance and adaptation are particularly inadequate.In our study,the aims are to reveal physiological strategies of Populus deltoides against drought stress under different soil conditions and to select the most suitable soil type for P.deltoides plantation.Methods Under controlled conditions,we used P.deltoides as a model species to detect differences in gas exchange rate,antioxidative capacity,nitrogen metabolism and biomass accumulation and partitioning in response to drought stress under three mineral soil types with distinct physicochemical characters,i.e.red soil(RS),yellow soil(YS)and yellow-brown soil(BS).Important Findings Exposure to 25%of field water holding capacity in soil for 3 months had significantly decreased biomass of all organs,photosynthetic rate,enzyme activities related to N assimilation,but increased H2O2,malondialdehyde and content of both NO3−and NH4+,when P.deltoides was planted in both RS and YS.In contrast,under BS,there are slightly negative effects exerted by water deficit on total biomass,gas exchange rate,activities of enzymes related to nitrogen metabolism and membrane damage caused by reactive oxygen species,which can be associated with a consistent increase in superoxide dismutase,peroxidase and catalase,and a higher ratio of root mass to shoot mass.It is concluded that,such higher capacity in tolerance and adaptation against drought stress under BS relative to both RS and YS could be accounted for more sufficient nutrient provision in soil parental materials and better soil aeration conditions which play a vital role in plant acclimation to water shortage.Our study also revealed that,distribution areas of BS might be preferable for cultivation of P.deltoides,when compared with those of RS and YS.
