title: Positional relationship between the gamete fusion site and the first division plane in the rice zygote.
abstract: In angiosperms, a zygote generally divides into a two-celled proembryo consisting of an apical and a basal cell that possess different cell fates. This first division of the zygote is a putative step in the formation of the apical-basal axis of the proembryo. The gamete fusion activates the egg, and the gamete fusion site on the zygote has been reported to provide a possible cue for subsequent zygotic development and/or embryonic patterning in animals and plants. In this study, the gamete fusion site on the rice zygote was labelled by in vitro fertilization of a rice egg cell with a fluorescence-stained sperm cell. The positional relationship between the gamete fusion site and the division plane formed by zygotic cleavage was monitored using a fixed culture of the fusion site-labelled zygote until the two-celled proembryo stage. The results indicate that gamete fusion sites exist on two-celled proembryos with no relation to the position of the first division plane, and that the gamete fusion site on the rice zygote does not function as a determinant for positioning the zygote division plane.
authors.affiliation: Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa Hachioji, Tokyo 192-0397, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nakajima
authors.forename: Takao
authors.initials: T
authors.lastname: Uchiumi
authors.forename: Takashi
authors.initials: T
authors.lastname: Okamoto
mesh_terms: D002455:Cell Division; D002459:Cell Fusion; D055993:Germ Cells, Plant / Q000166:cytology*; D012275:Oryza / Q000166:cytology*; D015053:Zygote / Q000166:cytology*
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