Sterility in angiosperms, Biology

Assignment Help:

Sterility in Angiosperms

Sterility in angiosperms may arise due to several causes. Either the anther may not be formed, or anthers are formed but meiosis may be abnormal.

A. In situations where anthers are not formed, they may take abortive forms and appear like petals or sepals. These conditions are referred to as petaloid and phyllody respectively. There are even cases where anther formation may be suppressed altogether. These cases of pollen sterility have premeiotic determination.

B. There are other examples in which anthers are produced but meiosis is abnormal resulting in the formation of non-viable pollen.

C. Sometimes normal pollen grains are formed but they are not released. This results from failure of anther dehiscence. Such a situation is also described by the term contabiscent anther.

D. Sometimes meiosis is normal but abortion can take place due to premature dissolution of callose. This can occur at any stage during microsporogenesis.


Related Discussions:- Sterility in angiosperms

Target organ damage, Central Nervous System   Hypertension is one of th...

Central Nervous System   Hypertension is one of the leading causes of cerebrovascular disease. It has been associated with accelerated age related cognitive decline. The most d

Dietary management of constipation, Q. Dietary Management of Constipation? ...

Q. Dietary Management of Constipation? Management of constipation lies in developing regularity of habit through a bowel- training programme and by establishing good healthy ha

How to investigate aortic stenosis by cardiaccatheterization, Q. How to inv...

Q. How to investigate aortic stenosis by Cardiac Catheterization? The indications are to confirm hemodynamics when the non-invasive tests are not conclusive or there is a disc

Animal Respiration, What type of respiration does earthworm has ? In many c...

What type of respiration does earthworm has ? In many complex animals, the cells of internal organs are distant from the outside environment; respiratory systems provide the passag

Glycogen synthesis, To synthesize glycogen two enzymes are needed: 1.  U...

To synthesize glycogen two enzymes are needed: 1.  UDP-glucose   pyrophosphorylase catalyzes the synthesis of UDP-glucose from UTP and glucose 1-phosphate:   The   py

Explain food plan for an anaemic pregnant lady, Explain Food plan for an an...

Explain Food plan for an anaemic pregnant lady? Justification of the Plan: The plan is for an anaemic pregnant lady, from a lower socio-economic level and doing moderate lev

Explain phenetic classification, Phenetic Classification This system is ...

Phenetic Classification This system is based exclusively upon face value of observed characters without direct reference to phylogeny. The taxa are either classified on the basi

Influence of lv function, Influence of LV Function :  LV functions, whethe...

Influence of LV Function :  LV functions, whether normal or impaired is important while selecting a patient for CABG and for long-term results of surgical revascularisation. If le

Pisces, what is the mode of nutrition in pisces

what is the mode of nutrition in pisces

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