Understanding how nutrient absorption processes in plants are related to arbuscular mycorrhizal(AM)association is critical for predicting the effects of AM symbiosis on elemental cycling for plants. Both mulberry(Moru...Understanding how nutrient absorption processes in plants are related to arbuscular mycorrhizal(AM)association is critical for predicting the effects of AM symbiosis on elemental cycling for plants. Both mulberry(Morus alba) and Chinese prickly ash(Zanthoxylum bungeanum) are AM-associated plants, widely distributed in southwest China. It was hypothesized that if the nutrient absorption processes were efficiently associated with AM symbiosis in both mulberry and Chinese prickly ash, foliar nutrient concentrations—especially calcium(Ca)—would be primarily determined by the soil conditions in different regions. To investigate this, AM colonization levels of soils, nutrient levels in soils and leaves, and δ^(13)C values of leaves were analyzed for mulberry and Chinese prickly ash.In this study, spore density in soils with low p H was higher than that in soils with high p H. The average concentrations of sugar delivered to roots in both mulberry and Chinese prickly ash in soil with relatively low p H and soil extractable cations were higher than those in other areas.The values of foliar δ^(13)C in both mulberry and Chinese prickly ash in low soil-pH and soil extractable cations were lower than those in contrast areas, indicating that water availability was impacted by soil characteristics. The efficiency in AM-mediated processes might play an important role in translocation between soil nutrients and plant tissue.The results suggest uptake and translocation of nutrients,especially Ca, in AM-associated plants may be affected by an efficiency of AM-mediated processes. Since Sr does not appear to be similarly affected, expressing Ca and other nutrient concentrations relative to Sr could be used to evaluate whether the uptake and translocation of Ca and other nutrients are affected by AM-mediated processes.展开更多
Persistence behavior of imidacloprid and beta-cyfluthrin in black pepper was studied following application of formulation of Solomon at 0.6 （recommended dose） and 1.2 （double recommended dose） g a.i./ha for one pe...Persistence behavior of imidacloprid and beta-cyfluthrin in black pepper was studied following application of formulation of Solomon at 0.6 （recommended dose） and 1.2 （double recommended dose） g a.i./ha for one pepper production cycle. The results also showed that the Solomon at 0.6 mL/L concentration significantly suppressed the pest infestation in pepper vines. Pepper vine treated with Solomon produce more berries compared to control and showed no phytotoxicity. Analytical procedure of Solomon active ingredient was validated prior to actual analysis. Satisfactory recoveries ranging between 87.6%-106.7% were obtained for the fortified pepper berries samples. Results showed low level of imidacloprid and beta-cyfluthrin residues in dried pepper berries ranging between 〈 0.01 mg/kg to 1.43 mg/kg and 〈 0.01 mg/kg to 1.612 mg/kg respectively. The half-life value period for imidacloprid were found to be 2.06 and 2.30 days and for beta-cyfluthrin, these values were observed to be 1.57 and 1.49 days respectively at recommended and double recommended dose. Imidacloprid and beta-cyfluthrin residue dissipated below the limit of quantification （LOQ） of 0.01 mg/kg after 7 and 9 days respectively at recommended and double recommended dose. Soil sample collected 15 days after the last spray did not show the present of Imidacloprid and beta-cyfluthrin residue at their detection limit of 0.01 mg/kg.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant no.4121004)water project of MEP (2012ZX07503003001)
文摘Understanding how nutrient absorption processes in plants are related to arbuscular mycorrhizal(AM)association is critical for predicting the effects of AM symbiosis on elemental cycling for plants. Both mulberry(Morus alba) and Chinese prickly ash(Zanthoxylum bungeanum) are AM-associated plants, widely distributed in southwest China. It was hypothesized that if the nutrient absorption processes were efficiently associated with AM symbiosis in both mulberry and Chinese prickly ash, foliar nutrient concentrations—especially calcium(Ca)—would be primarily determined by the soil conditions in different regions. To investigate this, AM colonization levels of soils, nutrient levels in soils and leaves, and δ^(13)C values of leaves were analyzed for mulberry and Chinese prickly ash.In this study, spore density in soils with low p H was higher than that in soils with high p H. The average concentrations of sugar delivered to roots in both mulberry and Chinese prickly ash in soil with relatively low p H and soil extractable cations were higher than those in other areas.The values of foliar δ^(13)C in both mulberry and Chinese prickly ash in low soil-pH and soil extractable cations were lower than those in contrast areas, indicating that water availability was impacted by soil characteristics. The efficiency in AM-mediated processes might play an important role in translocation between soil nutrients and plant tissue.The results suggest uptake and translocation of nutrients,especially Ca, in AM-associated plants may be affected by an efficiency of AM-mediated processes. Since Sr does not appear to be similarly affected, expressing Ca and other nutrient concentrations relative to Sr could be used to evaluate whether the uptake and translocation of Ca and other nutrients are affected by AM-mediated processes.
文摘Persistence behavior of imidacloprid and beta-cyfluthrin in black pepper was studied following application of formulation of Solomon at 0.6 （recommended dose） and 1.2 （double recommended dose） g a.i./ha for one pepper production cycle. The results also showed that the Solomon at 0.6 mL/L concentration significantly suppressed the pest infestation in pepper vines. Pepper vine treated with Solomon produce more berries compared to control and showed no phytotoxicity. Analytical procedure of Solomon active ingredient was validated prior to actual analysis. Satisfactory recoveries ranging between 87.6%-106.7% were obtained for the fortified pepper berries samples. Results showed low level of imidacloprid and beta-cyfluthrin residues in dried pepper berries ranging between 〈 0.01 mg/kg to 1.43 mg/kg and 〈 0.01 mg/kg to 1.612 mg/kg respectively. The half-life value period for imidacloprid were found to be 2.06 and 2.30 days and for beta-cyfluthrin, these values were observed to be 1.57 and 1.49 days respectively at recommended and double recommended dose. Imidacloprid and beta-cyfluthrin residue dissipated below the limit of quantification （LOQ） of 0.01 mg/kg after 7 and 9 days respectively at recommended and double recommended dose. Soil sample collected 15 days after the last spray did not show the present of Imidacloprid and beta-cyfluthrin residue at their detection limit of 0.01 mg/kg.
