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

How are the transparency and functions of cornea evaluated, How are the tra...

How are the transparency and functions of cornea evaluated? Physiological roles of barrier function, refractive function (with interaction of tear film), response to wound and

Proteins, Amino Acid - compound with an amino group and a carboxyl group a...

Amino Acid - compound with an amino group and a carboxyl group attached to a central carbon Proteins make up 50% of dry mass of cells in our bodies E.g. of proteins are

What is nagel''s anomaloscope, What is Nagel's Anomaloscope The patient...

What is Nagel's Anomaloscope The patient is asked to match a yellow with a mixture of red and green wave lengths. A defect can be detected based on the amount of red and green

Explain about the absorbed moisture - water found in food, Explain about th...

Explain about the Absorbed Moisture - water found in food? It is the moisture that has passed through cell walls and entered the cytoplasm of the cell. It is this form of water

What is yersiniosis, What is yersiniosis? Give its symptoms. Yersiniosi...

What is yersiniosis? Give its symptoms. Yersiniosis caused by the bacteria Yersinia enterolytica.   •  Causes severe abdominal pain, fever and diarrhoea.

What is the function of the umbilical cord, What is the function of the umb...

What is the function of the umbilical cord? The umbilical cord haves blood vessels which convey blood among the fetus and the placenta.

Northern blot, Northern blot is a technique for analyzing mixtures of RNA ...

Northern blot is a technique for analyzing mixtures of RNA by transfer of size-separated RNA fragments to a synthetic membrane, the presence and rough size of one particular type

Cell theory, why is virus an exception of cell theory

why is virus an exception of cell theory

Reproductive mechanisms, Normal 0 false false false EN-...

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

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