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

Which organs form the human respiratory system, Q. What are the organs that...

Q. What are the organs that form the human respiratory system? The organs that are part of the human respiratory system can be divided into three groups: lungs, respiratory mus

Compound or multilayered epithelia, COMPOUN D EPITHELIA (MULTILAYERED EPIT...

COMPOUN D EPITHELIA (MULTILAYERED EPITHELIA) - These are made up of more than one layer of cells. The compound epithelia may be stratified and transitinal. 1 .

Give an introduction to intensive care, Give an introduction to intensive c...

Give an introduction to intensive care ? Intensive Care Medicine has its origins from the polio epidemic of 1952 in Copenhagen. Patients who suffered respiratory paralysis were

Limnology, Limnology : It is the study of organisms present in rivers or fr...

Limnology : It is the study of organisms present in rivers or fresh water lakes. Limnology is also called as freshwater science. This is the study of inland waters. Limnology is of

Define the activation of an agonist during movement, Explain the relationsh...

Explain the relationship between an agonist muscle and its antagonist as it relates to positional control, functional movement and neuromuscular activation. For example, how the th

What is protein synthesis, What is Protein Synthesis? Protein Synthesi...

What is Protein Synthesis? Protein Synthesis :  Protein synthesis begins in the nucleus, with the formation of mRNA from a DNA template through transcription. The function of

Explain complete and incomplete digestive system , Normal 0 fal...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Explain the principle of development, Explain the Principle of Development ...

Explain the Principle of Development The final guiding principle is that assessment involves the measure of change, or development, across multiple levels of analysis. Developm

What are the main events of the first mitotic period, What are the main eve...

What are the main events of the first mitotic period? The first mitotic period is prophase. During prophase the following events happen: migration of each centriole pair (centr

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