Study of Floral Organ Differentiation and Embryology in Eupatorium adenophorum — an Exotic Plant

We observed floral organ differentiation, megasporogenesis, microsporogenesis and the embryogenetic process in Eupatorium adenophorum by the paraffin section method. The floral bud differentiated when the diameter of the anthodium was between 0 and 1.6-1.8 mm, and microspores, megaspores, microgametophytes and megagametophytes developed when the diameter of the anthodium was between 1.8-2.0 mm and 3.8-4.0 mm. Pollen mother cell meiosis mainly occurred when the diameter of the anthodium was between 2.3 and 3.5 mm. Simultaneous cytokine styles, secretory tapeta, 3-celled mature pollen grains, dicotylous-developed anther walls and the polygonum type of mature embryo sacs were detected. In addition, the mature ovule was anatropous, unitegmic and tenuinucellate. A biembryo was found during the embryonic development period.