Abstract: It's found that ⁶⁰Co and ¹³⁷Cs concentrated by Plalymonas sp.can be washed out with 0.5% ethylene diamine sodium teracetate.The washed amount is decreased with increasing time of concentration and stabilized in the range of 42—48% after 16 hours.Loss experiment shows thatthe amount of ⁶⁰Co and ¹³⁷Cs in Plalymonas sp.is influenced by biotic dilution after cell multiplication.Potasium cyanide and iodcacetic acid can slightly inhibit the concentration of ⁶⁰Coand ¹³⁷Cs when added previously.However,when the inhibitors are added with ⁶⁰Co and ¹³⁷C sat the same time,the concentration of nuclides are premoted.It's considered that this promotion is not physiological action but physical and chemical adsorption.

Key words: Natural forest, Pinus densiflora, Individual biomass, Stand density