FLOW CYTOMETRIC CHARACTERIZATION OF EMBRYOGENIC AND GAMETOPHYTIC DEVELOPMENT IN BRASSICA-NAPUS MICROSPORE CULTURES

Microspore cultures are ideal systems for studying plant embryogenesis because the resulting embryos are very similar to zygotic embryos, al l the stages of development are readily accessible and the process can be induced by a simple heat treatment. However, not all microspores a re embryogenic and the mixture of cells that develops in the cultures complicates the use of this system. Brassica napus microspore cultures cultured at 30 degrees C (induced) and at 25 degrees C (non-induced) were compared by flow cytometry to obtain structure and function infor mation for several types of cells in the culture. Clear differences in light scatter and fluorescence were found between induced and nonindu ced cultures that are related to early stages of embryo development. V iable, round cells that were unique to induced cultures were sorted in to culture media and developed into embryos confirming that they were embryogenic. The present study provided flow cytometric identifiers fo r embryogenic and gametophytic cells, demonstrated how flow sorting ca n be used to isolate specific cell types and defined benchmarks for as sessing the embryogenic potential of microspore cultures.