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

Prevention and control of staphylococcal food poisoning, Q. Prevention and ...

Q. Prevention and Control of Staphylococcal food poisoning? Staphylococcal food poisoning can be prevented by: 1. Avoiding contamination of food with S. aureus. 2. Prev

What are heterochromatin and euchromatin, Chromatin is uncondensed nuclear ...

Chromatin is uncondensed nuclear DNA, the typical DNA morphology in interphase (the phase of the cell cycle in which the cells is not separating itself). In this phase of the cell

Define equilibrium between two solid phases and a gas phase, Define Equilib...

Define Equilibrium between two solid phases and a gas phase? Consider the following reaction equilibrium: 3 CuO(s) + 2NH 3 (g) ↔ 3 Cu(s) + 3H 2 O (g) + N 2 (g) Accordin

How time affecting taste quality, Q. How Time affecting taste quality? ...

Q. How Time affecting taste quality? Time- Time is another factor which affects sensation. Salt on tongue is sensed in a fraction of a second; whereas, bitter things may requir

How to reduce the stresses on the implant, How to reduce the stresses on th...

How to reduce the stresses on the implant i) There is need to reduce the stresses on the implant - ii) Frequent recall for maintenance or hygiene appointments. iii) Gingi

Parasitology, how trematodes/nematodes adapt to their parasitic mode of fee...

how trematodes/nematodes adapt to their parasitic mode of feeding

Cardinal manifestation of cardiovascular disorders, CARDINAL MANIFESTATION ...

CARDINAL MANIFESTATION OF CARDIOVASCULAR DISORDERS Cardiovascular symptoms that most often trouble patients are: 1. Chest Pain 2. Shortness of Breath 3. Palpitation

Anaemia, A n a e m i a It is defined as decrease in the amount of...

A n a e m i a It is defined as decrease in the amount of haemoglobin (Hb) per unit of blood. This may or may not be accompanied by a reduction in the red blood cells (RBC

Phylum annelida, describe the diversity in the feeding habits and locomotio...

describe the diversity in the feeding habits and locomotion of annelids

Show the circulatory system present in arthropods, Q. What is the kind of c...

Q. What is the kind of circulatory system present in arthropods? Do these animals have respiratory pigments and heart? In arthropods the respiratory system is open (lacunar). B

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