Gonial apospory and somatic apospory, Biology

Assignment Help:

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.


Related Discussions:- Gonial apospory and somatic apospory

Non - pharmacological management, Great importance is being given to life s...

Great importance is being given to life style modifications because of definite benefits observed in patients who follow this. Life style changes have advantages not only in the co

Messenger rna (mrna), Messenger RNA (mRNA) are the proteins are not synthe...

Messenger RNA (mRNA) are the proteins are not synthesized directly from the genomic DNA. Insteadof that an RNA template (a precursor mRNA) is constructed from the sequence of gene

What is the natural habitat of e.coli, What is the natural habitat of E.col...

What is the natural habitat of E.coli? The E.coli was first recognized in the colon region of large intestine and so it was given the name "coli" (found in colon) they are coli

Morphogenesis of an ectodermal derivative, Morphogenesis of an Ectodermal D...

Morphogenesis of an Ectodermal Derivative During the development of vertebrate body the dissimilar regions in the three germ layers of the gastrula become segregated from each

How d-glucose differs from d-galactose, D-glucose differs from D-galactose ...

D-glucose differs from D-galactose only in the arrangement around carbon 4. Therefore D-glucose and D-galactose are- Select one: a. enantiomers b. epimers c. mirror ima

Define self monitoring of blood glucose, Q. Define Self Monitoring of Blood...

Q. Define Self Monitoring of Blood Glucose? Self Monitoring of Blood Glucose (SMBG): A patient can monitor the glucose level at home by self using the glucometer for checking t

Define type of chemical reaction used in volumetric analysis, Define the Ty...

Define the Type of chemical reaction used in volumetric analysis? The titration has to be based on some rapid chemical reaction. Although any type of chemical reactions may be

What is sick sinus syndrome, Q. What is Sick Sinus Syndrome? Ans. ...

Q. What is Sick Sinus Syndrome? Ans. When a slow resting pulse fails to accelerate normally with exercise, it has been labeled chronotropic incompetence, however, there i

What are examples of the ecological and economic, What are examples of the ...

What are examples of the ecological and economic importance of molluscs? Molluscs are significant players in several food chains in ecosystems. Many marine molluscs are part of

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd