Gonial apospory and somatic apospory, Biology

Gonial Apospory and Somatic Apospory

Gonial Apospory

There is no meiosis. The megaspore mother cell enlarges; a small vacuole appears above and below the nucleus. The cell thus becomes 1-nucleate embryo sac. Three successive mitotic divisions result into an 8-nucleate embryo sac. In Brachycome, the polar nuclei function directly as the first 2 endosperm nuclei.

Somatic Apospory

Meiosis is apparently normal but megaspores play no part in the embryo sac formation. Either during or soon after meiosis one or more sporophytic cells (nucellar or chalazal) enlarge and invade the nucellar lobe destroying and replacing the megaspore. After 3 successive nuclear divisions each such cell becomes differentiated into an aposporic 2n embryo sac with normal organization. Thus, gametophytic generation is completely eliminated.

Posted Date: 1/23/2013 5:57:42 AM | Location : United States







Related Discussions:- Gonial apospory and somatic apospory, Assignment Help, Ask Question on Gonial apospory and somatic apospory, Get Answer, Expert's Help, Gonial apospory and somatic apospory Discussions

Write discussion on Gonial apospory and somatic apospory
Your posts are moderated
Related Questions
The substance that is worked on by an enzyme is called: a. product b. coenzyme c. substrate d. inhibitor

Define the Basic Types of Drying Process? Primarily, there are three basic types of drying process: a) Sun drying and solar drying;  b) Atmospheric drying including batch

How can the concept of recombination frequency be used in genetic mapping? Genetic mapping is the determination of the location of the genes in a chromosome. By determining

Q. Briefly explain about Type Specimens ? The specimens on which the names of the species are based are kept as type specimens. Do not replace these specimens because these wi

Determine the term - Akinetic and Myoclonic Seizures Akinetic seizures are ordinarily seen only in children. Usually, an affected child collapses suddenly and without warning.

Define about the Probiotics? Dietary Sources and their Mode of Action/Effects We can have specific preparations designed for probiotic use, as well as, foods. Probiotic product

A vertical section of an ovule is shown below.  The correct ploidy levels of the four structures P, Q, R and S respectively are: a.  n, 2n, n, n b.  2n, n, n, n c.


What is Iris Coloboma Coloboma is a congenital abnormality due to non-fusion of the embryonic choroidal fissure. It can affect any part of the eye and may involve the optic ner

Explain the Evaluation of the Perimplant Marginal Tissues This is to be followed by Evaluation of the Perimplant Marginal Tissues: This includes the following parameters: 1)