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

Levels of prevention and role of a nurse, LEVELS OF PREVENTION AND ROLE OF ...

LEVELS OF PREVENTION AND ROLE OF A NURSE: Caplan describes the levels of  prevention as follows:  1)   Primary Prevention  It is concerned with  reduction of  incidence

Objectives of dietary management of myocardial infarction, Q. Objectives of...

Q. Objectives of dietary management of myocardial infarction? The objectives of dietary management of myocardial infarction patients are as follows: - To provide rest to the

applied biology, what is definition of applied biology

what is definition of applied biology?

Hormones secreted by thyroid gland, Hormone s . The thyroid gland secretes...

Hormone s . The thyroid gland secretes following hormones. Thyroxine (tetraiodothyronine or T 4 )' and tri-iodothyronine or T 3 are secreted by the thyroid follicular cells.

Bacterial motility, What morphological structure is responsible for bacteri...

What morphological structure is responsible for bacterial motility?

Gastrulation in some animals, Gastrulation in some Animals As mentione...

Gastrulation in some Animals As mentioned before gastrulation marks the beginning of morphogenesis that is development of body form and organisation of cells in the embryo. By

Explain the right ventricle from the pulmonary artery, What is the valve th...

What is the valve that separates the right ventricle from the pulmonary artery? Why is that valve significant? The valve that divides the right ventricle and the base of the p

Determine about the accommodation of eye, Determine about the Accommodation...

Determine about the Accommodation of eye Accommodation is the ability of the overall refracting power of the eye to change to clearly view objects at different distances. This

Explain the principle of nelson-somogyi method, Explain the Principle of Ne...

Explain the Principle of Nelson-Somogyi Method? Glucose is estimated by Nelson-Somogyi method. We begin our study of this method by getting to know the principle involved in th

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