Ultrastructural Observations on Microspore Development in Rice Anther Culture
The plants produced from rice anther culture varied in ploidy level. Genetic analysis of anther-derived plants indicated genome multiplication occurred in microspore development in vitro. Cytological studies on early roicrospore division suggested endoreduplication and nuclear fusion may be related to the production of nonhaploid plants. In the present study, fine structures of callus ontogeny in anther culture were emphasized.Anthers of rice(Oryza sativa L. c. v. Hsinchu 4, 2n=24) containing mid-uninucleate microspores were excised and cultured in Ng liquid medium, supplimented with 60 g/l sucrose, 1 mg/l kinetin and 2 mg/l naphthalenacetic acid. Cultured anthers were collected at 2 days intervals for 20 days and fixed in 2.5% glutaraldehyde in 0.1M cacodylate buffer(pH=7.0), postfixed in osmium tetraoxide, and then embedded in Spurr's resin. Thin sections were stained with uranyl acetate and lead citrate, observed under Hitachi H-600 at 75 KV.