Abstract: Two kinds of divisions, equal and unequal, of uni-nucleate pollen of poplar anthers were observed in artificial culture, particularly the former. The nucleus vegetatively derived from both divisions could developed into globular embryos, and formed an irregular callus further.By cytological observation, the callus which emerged from the anthers were originated from the pollen. Its chromosomes are haploid. The chromosome numbers in the root tip of plantlets which derived from the haploid callus are also haploid, such as Populus serotina 272, No, 11, 26, and 45.Callus were induced from poplar anthers which cultured in vitro on medium with MS+2,4-D 0.5-2mg/l+Kinetin 0.2—2mg/l. However, the callus of different species and varieties were in need of various combinations of MS medium composed of 2,4-D and kinetin, when the anthers of Poplus were treated by centrifuge at 2000 rev./min, for 20 minutes and cultivated on MS+2, 4-D 2mg/l+Kinetin 2mg/l medium, the frequency of callus was greatly increased. Adding 50—150mg/l yeast Ribonucleic acid (Y-RNA) to the above medium, the inducing frequency of pollen callus were also efficiently increased. Besides, it appeared that the Y-DNA played an important role in the promotion to initiate the pollen development.While the pollen callus were transfered on MS+BAP 2mg/l+NAA 0.3 mg/l+IAA 0.1mg/l medium, they differentialted into rootless plantlets. The differentiation frequency of shootlets was 90%. Medium with 1/2 MS+IAA 1mg/l was quits suitable for root-system formation in shootlets. Its induction frequency of plantlets was 80—90%.