W13 Flashcards
How is the cell fate of Aradopsis unusual for plants?
Cell divisions are regular and are exactly predictable.
What happens at the 1st division of arabidopsis?
Cell divides asymmetrically to produce a small top cell (embryo) and a larger bottom cell (extra-embryonal suspensor.
What is the role of the endosperm in the embryos development?
Gives nourishment to the plant- different from plat to plant.
What are the two types of maternal effect?
- Sporophytischer Maternaleffekt
- gametophytischer maternaleffekt.
1. cytoplasmatischer Effekt
2. genetische Prägugn (Genomic imprinting)
3. dene dosage effect in endosperm - media-mutante : 50% Embryomortalität.
What is the o’-line?
It seems to be a compartment boundary, as cell cannot cross.
Develops at 16 cell stage
What does the phenomenon of twin mutants show?
In twin mutants one of the cells in the suspensor becomes a second embryo. This shows that all cells have the potential to become an embryo, and positional information stops it.
The embryo proper normally inhibits this.
How does the knolle mutation affect pattern formation?
The error in pattern formation can be traced back to the fist divisions of the embryo. They do not happen in the stereotypical way.
How do knolle and gnome function?
They influence vesicle transport.
What is the important substance in pattern formation?
Auxin and pin transportation.
e.g gnome affects the location of pin.
What are the parts of the seed?
- Sameschale (2n maternal)
- Embryo (2n maternal and paternal)
- Endosperm (3n, 2 maternal 1 paternal)
What are the stages of Arabidopsis development?
- zygote (one cell)
- 1 cell (first division separated embryo and suspensor)
- 8 cell stage (vertical division occurs before horizontal division)
- 16 cell stage (0’-line forms)
- early globular
- late globular (LSC-lense shaped cell forms)
- transition
- torpedo (late heart)
- seedling.
