Abstract Detail

Recent Topics Posters

Jones, Daniel [1], Chesnut, Joshua [2], Russell, Scott [1].

Three-dimensional visualization of the embryo sac of Oryza sativa through fertilization.

In most angiosperms the female gametophyte consists of a seven celled, eight nucleate Polygonum type embryo sac containing two synergids, an egg cell, a diploid central cell (with two fused polar nuclei) and three antipodals. These cell types have been defined to have unique functions during reproduction, ranging from pollen tube attraction (synergids) to double fertilization (egg cell (EC) and the central cell (CC)). The processes that occur within the embryo sac (ES) during fertilization have been well-studied using light and transmission electron microscopy. However, the complex, three-dimensional nature of this system can make it difficult to fully understand these dynamics using a two-dimensional media. In this study, we imaged the ES of Oryza sativa ssp. japonica on the day of anthesis and after fertilization (30 min – 14 hrs) using a Leica TCS SP8 multiphoton microscope. Images were taken in a z-series using cubic voxels (~150nm X 150nm X 150nm) through the entirety of the ES. Three-dimensional images were then rendered with the raw fluorescence data using Imaris (Bitplane) in order to reconstruct the structure of the ES. This 3D visualization highlights the complexity of the CC membrane and its associations throughout the ES. At maturity, the EC and two synergids (egg apparatus) are highly associated at the micropylar end of the ES, enclosed within an inlet of the CC membrane with the partially fused polar nuclei closely positioned above. The group of 10-15 antipodal cells is positioned directly across from the egg apparatus along the middle of the opposing ES wall also associated with the CC membrane. At 30min the pollen tube aperture can be identified along with a degenerate synergid, suggesting the delivery of sperm cells. By 2hrs plasmogomy and karyogamy have both occurred and a zygote is formed. After 14hrs the zygote has undergone an asymmetric division producing a basal and apical cell and at least six primary endosperm nuclei are present indicating several rounds of endosperm divisions. During each time point, an increase in the number of antipodals was observed. The 3D rendering of embryo sacs gives a novel view into structures and processes only previously captured in single sections. The optimization of a fixation protocol will lead to more insights into the native progression of ES development and fertilization events. 

Broader Impacts:

1 - University of Oklahoma, Department of Microbiology And Plant Biology, 770 Van Vleet Oval, Norman, OK, 73019-6155, USA
2 - The University of Oklahoma, Department of Microbiology and Plant Biology, 770 Van Vleet Oval, Norman, OK, 73019, USA

Keywords:
Embryo Sac
reproduction
Confocal laser scanning microscopy.

Presentation Type: Recent Topics Poster
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PRT044
Abstract ID:1341
Candidate for Awards:None