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

Foot-and-mouth disease, Foot-and-mouth disease Foot-and-mouth disease ...

Foot-and-mouth disease Foot-and-mouth disease (FMD) is an extremely contagious viral disease of cloven footed animals most notably cattle, pig and sheep. It is well known for

Compute the amount of nacl need, A saline drip is to be prepared for a lab ...

A saline drip is to be prepared for a lab experiment that is looking at hydration in lab rats. Calculate the amount of NaCl need to make 4 liters of a 0.9% solution.

Define the best describes this autopsy finding, A 70-year old woman present...

A 70-year old woman presents with a 1-hour history of crushing substernal chest pain. Shortly after admission, the patient expires. An autopsy reveals calcium deposits in the intim

How many different molecules composed, How many different molecules compose...

How many different molecules composed of (A) two (B) three, and (C) four amino acids, linked together by peptide bonds, can be made from the set of 20 naturally occurring amino aci

Experiments do not support the hypothesis, If experiments do not support th...

If experiments do not support the hypothesis, the hypothesis is always rejected or wrong. True or False?

Compare between mummers of dna vs monomers of rna, Name few polymers in the...

Name few polymers in the eukoratic cell? Name the mummers that make up the DNA? Compare and contrast between mummers of DNA VS monomers of RNA?

Define visible hazards in food, Normal 0 false false false ...

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

Cell membrane, CELL MEMBRANE It is biological, thin, elastic, flexib...

CELL MEMBRANE It is biological, thin, elastic, flexible & selective permeable membrane. Term "Cell membrane" was coined by Negeli & Crammer 1855. Term " Plasma membr

Medicinal value - conservation of wildlife, Medicinal Value - Conservation ...

Medicinal Value - Conservation of Wildlife About 40% of all drugs used throughout the world have active ingredients extracted from plants and animals. The world-wide annual sa

Historically what were the two main evolutionary theories, Historically wha...

Historically what were the two main evolutionary theories? The two major evolutionary theories were darwinism and lamarckism.

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