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

Explain identifying features of rhizopus - food microbiology, Explain Ident...

Explain Identifying features of Rhizopus? Macroscopically Rhizopus appears as a white cottony mass (look at rhizopus growth on media above) growing rapidly and spread over enti

Explain the characteristics of a biological community, Which one of the fol...

Which one of the following is one of the characteristics of a biological community? 1.  Stratification 2. Natality 3. Mortality 4. Sex-ratio   Stratification

Galvanotaxis - modes of cell movement, Galvanotaxis - Modes of Cell Movemen...

Galvanotaxis - Modes of Cell Movement Galvanotaxis considers to the movement of cells in response to a potential variation between cells. It is suggested that there are voltag

Postparturient haemoglobinuria, Post pa r turient haemoglobinuria It...

Post pa r turient haemoglobinuria It is also known as puerperal haemoglobinuria or nutritional haemoglobinurea and results in intravascular haemolysis, haemoglobinuria and a

Duck septicemia (duck pasteurellosis/new duck disease), D uck septicemia (...

D uck septicemia (duck pasteurellosis/new duck disease) The disease is caused by Pasteruella anatipestifer (Syn. Riemerella anatipestifer ) that mostly affects growing duck

Dissimmilarity between an ecosystem and a biome, What is the difference bet...

What is the difference between an ecosystem and a biome?

Nematodes, how nematodes adapt to their mode of feeding

how nematodes adapt to their mode of feeding

Bones, which bone forms the non-moving muscle attachment in the hip joint

which bone forms the non-moving muscle attachment in the hip joint

Immediate and longer term adjustment to altitude hypoxia, Define Immediate ...

Define Immediate and Longer term Adjustment to Altitude Hypoxia? Arterial hypoxia precipitates the immediate physiological adjustments to altitude and process of acclimatizatio

Laws of cleavage, L A W S OF CLEAVAGE - 1. Sac's Law - According t...

L A W S OF CLEAVAGE - 1. Sac's Law - According this law, during cleavage each blastomere to form similar blastomere. New cleavae always take place at the right angle of 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