Development of microsporesin vivo andin vitro inBrassica napus L.

Summary Populations of highly homogeneous uninucleate and binucleate microspores ofBrassica napus cv. Topas were obtained by bud selection and percoll fractionation. The development of the uninucleate and the binucleate microspores in culture was compared to thosein vivo using the fluorochrome DAPI to stain DNA. The major developmental pathway of the uninucleate microsporesin vitro resulted in embryo formation. The characteristic of this pathway was that the first division produced two diffusely stained nuclei and subsequent divisions gave rise to a multinucleate embryoid. The second pathway which occurred in a small number of the uninucleate microspores led to callus formation. The majority of the binucleate microsporesin vitro followed the developmental pattern of their counterpartsin vivo and were not embryogenic. The embryogenic binucleate microspores produced embryos through the divisions of the vegetative nucleus.Plant Research Centre Contribution # 1147