This paper presents a criterion for the similarity of length-two elements in a noncommutative principal ideal domain. The criterion enables the authors to develop an algorithm for determining whether B1A1 and B2A2 are...This paper presents a criterion for the similarity of length-two elements in a noncommutative principal ideal domain. The criterion enables the authors to develop an algorithm for determining whether B1A1 and B2A2 are similar, where A1, A2, B1, B2 are first-order differential （difference） operators. The main step in the algorithm is to find a rational solution of a parametric differential （difference） Risch＇s equation, which has been well-studied in symbolic integration （summation）.展开更多
Pinus tabulaeformis seedlings were grown under a factorial design to measure biomass accumulation and P, Na and K concentrations of plants, with 3 different ectomycorrhizal fungus (EMF) strains (Boletus edulis, Xeroco...Pinus tabulaeformis seedlings were grown under a factorial design to measure biomass accumulation and P, Na and K concentrations of plants, with 3 different ectomycorrhizal fungus (EMF) strains (Boletus edulis, Xerocomus chrysenteron and Gomphidius viscidus) and two P treatments (with or without extra P). Growth and mineral nutrition of pine seedlings were stimulated by three EMF under salinity stress. Na concentrations were changed and plant K and P concentrations were increased significantly by EMF. Adding extra P made no difference in accumulation of seedlings biomass, and did not assist element absorption of plants. Although three strains of EMF can all enhance the tolerance of pine seedlings to salinity stress, they may utilize different mechanisms because of different performance in absorption of elements. The increased P and K accumulation and the balance of ion concentrations might be due to the enhanced tolerance of EMF-inoculated plants to saline conditions.展开更多
基金supported by a 973 key project under Grant No.2004CB318000the National Natural Science Foundation under Grant No.76596100
文摘This paper presents a criterion for the similarity of length-two elements in a noncommutative principal ideal domain. The criterion enables the authors to develop an algorithm for determining whether B1A1 and B2A2 are similar, where A1, A2, B1, B2 are first-order differential （difference） operators. The main step in the algorithm is to find a rational solution of a parametric differential （difference） Risch＇s equation, which has been well-studied in symbolic integration （summation）.
基金Supported by the National Natural Science Foundation of China (No.4002101)
文摘Pinus tabulaeformis seedlings were grown under a factorial design to measure biomass accumulation and P, Na and K concentrations of plants, with 3 different ectomycorrhizal fungus (EMF) strains (Boletus edulis, Xerocomus chrysenteron and Gomphidius viscidus) and two P treatments (with or without extra P). Growth and mineral nutrition of pine seedlings were stimulated by three EMF under salinity stress. Na concentrations were changed and plant K and P concentrations were increased significantly by EMF. Adding extra P made no difference in accumulation of seedlings biomass, and did not assist element absorption of plants. Although three strains of EMF can all enhance the tolerance of pine seedlings to salinity stress, they may utilize different mechanisms because of different performance in absorption of elements. The increased P and K accumulation and the balance of ion concentrations might be due to the enhanced tolerance of EMF-inoculated plants to saline conditions.
