In Rhododendron spp. and Ledum groenlandicum a callose wall is laid down around the zygote in the first 2 days after fertilization. The periodic acid/Schiff-positive, aniline blue-fluorescence-positive callosic wall is initiated adjacent to the degenerating synergid, extends to cover the entire zygote surface, and remains visible during the initiation of embryogeny as the zygote elongates befor...

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 ...

background: multiple factors have been suggested for prediction of pregnancy in intracytoplasmic sperm injection (icsi) cycles such as the number of injected oocytes, fertilization rate, embryo morphology and quality of transferred embryos. predictive value of these factors is important in icsi outcome. objectives: to evaluate the role of embryo morphology for prediction of pregnancy in icsi cy...

The green alga Chlamydomonas reinhardtii elaborates two biochemically and morphologically distinct cell walls during its life cycle: one surrounds the vegetative and gametic cell and the other encompasses the zygote. Hydroxyproline-rich glycoproteins (HRGPs) constitute a major component of both walls. We describe the isolation and characterization of a zygote-specific gene encoding a wall HRGP....

In most flowering plants, the apical-basal body axis is established by an asymmetric division of the polarized zygote. In Arabidopsis, early embryo patterning is regulated by WOX homeobox genes, which are coexpressed in the zygote but become restricted to apical (WOX2) and basal (WOX8/9) cells. How the asymmetry of zygote division is regulated and connected to the daughter cell fates is largely...

The formation of the zygote in cotton is accompanied by marked changes in the number and aggregation of the ribosomes. The zygote is formed approximately 14 hr after pollination but does not divide for some 56-60 hr. Electron microscope studies of the zygote during this period reveal a series of changes in the size and distribution of polysomes which may provide information on this important st...

Auxin is an important plant growth regulator, and plays a key role in apical-basal axis formation and embryo differentiation, but the mechanism remains unclear. The level of indole-3-acetic acid (IAA) during zygote and embryo development of Nicotiana tabacum L. is investigated here using the techniques of GC-SIM-MS analysis, immunolocalization, and the GUS activity assay of DR5::GUS transgenic ...

The formation of the zygote in cotton is accompanied by marked changes in the number and aggregation of the ribosomes. The zygote is formed approximately 14 hr after pollination but does not divide for some 56-60 hr. Electron microscope studies of the zygote during this period reveal a series of changes in the size and distribution of polysomes which may provide information on this important st...