Abstract:A technique has been recently developed in our lab to isolate embryo sacs by means of enzymatic maceration of ovules (Zhou and Yang, 1982). In the pre sent paper this method was adopted in observing the whole processes of mtgasporgcnsis and megagametophyte development in Pauiownia sp. and Sesamum indicum. FPA fixed ovules were macerated in peetinase-eellulase solution with a microshaker, eleared in lactophenol, and then observed under a microscope with Nomarski interference contrast or phase contrast equipments. In both species, various developmental stages, from megasporocyte till mature embryo sac, were successfully identificd and described (Plate Ⅰ and Ⅱ). As a kind of microtechnique, enzymatic method shows some merits as its rapidness in specimen preparation and convenience for obtaining whole structural image Several technical points are discussed hereof.