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

Why on earth would be drinking milk to feel better, If a person has a stoma...

If a person has a stomach ulcer (that is aggravated by excessive hydrochloric acid {HCl} secretion ), why on earth would he or she be drinking milk to feel better, when milk is als

How to devise a series of dilutions, A solution was prepared by dissolving ...

A solution was prepared by dissolving 25g NaOH powder in 100 ml water. Using not more than 15 ml water, devise a series of dilutions that will give a concentration of 5mg/ml NaOH.

Explain the bioavailability of vitamin d, Explain the Bioavailability of Vi...

Explain the Bioavailability of Vitamin D? The nutritional availability of vitamin D is less significant because it can be endogenously produced and retained for long periods by

Define vitamins requirement to avoid underweight problem, Define Vitamins r...

Define Vitamins requirement to avoid underweight problem? Vitamins and Minerals: If the diet provides good amounts of fresh fruits and vegetables, vitamin or mineral supplement

Metazoa, explain hadzi''s theory with reference to metazoa

explain hadzi''s theory with reference to metazoa

Define food behaviour - public nutrition, Define Food Behaviour - Public Nu...

Define Food Behaviour - Public Nutrition? Food is not merely a means to survival but the fuel that drives the human body and the economic engine. What influences what we decide

How are amphibians characterized, Q. Amphibian identity card. How are amphi...

Q. Amphibian identity card. How are amphibians characterized according to examples of representing beings, basic morphology, circulation, skin, nitrogen waste, respiration, thermal

Explain genital herpes, Explain Genital herpes Acyclovir  (Zovirax,  a...

Explain Genital herpes Acyclovir  (Zovirax,  and others), famciclovir (Famvir) or valacyclovir (Valtrex) taken orally for 7-10 days shortens the duration of pain, viral sheddi

What are the main classes into which the phylum is divided, What are the ma...

What are the main classes into which the phylum is divided? What are some examples of each and in which form (polyp or medusae) are they found? Coelenterates are separated into

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