Abstract: In the experiments with hybridization between Populus alba × P.tomentosa and p. alba var. pyramidalis,the branches with male flowers were treated with rare earth element solutions at concentrations of 10,50 and 200ppm.The results showed that rare earth treatments increased the germination percentage of fresh pollens and delayed their vitality decline.And rare earth treatment at 200ppm was observed to have the best effects.The female flower oranches were also treated with rare earth solutions at 5,80,200 and 500ppm.The viability of seeds could be maitained for a long time after the treatments.These experiments proved that rare earth treatments could keep the cell membranes intact and slowed down the leakage of metabolities.t was found that the amount of oxygen absorbed by seeds and the vitality of dehydrogenase were inhanced,and the transportation rate of stored substances was speeded up.

Key words: P.alba × P.tomentosa, P.alba var. pyramidalis, Pollen, Seed, Activity of enzyme, Element of rare earth