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 vitamin e is directly related to selenium and pufa, How Vitamin E is di...

How Vitamin E is directly related to selenium and PUFA? Selenium: An inter-relationship exists between vitamin E and selenium, as selenium functions as an integral par1

A decrease in blood plasma levels of calcium, A decrease in blood plasma le...

A decrease in blood plasma levels of calcium will lead to A. an increase in the calcium ion excretion in the urine. B. an increase in the calcium ion absorption from the con

Explain the structure of a human sperm, (a) Explain the structure of a hum...

(a) Explain the structure of a human sperm. (b) Give a schematic representation showing the events of Spermatogeninesis in human male.

What is population density, What is population density? Population dens...

What is population density? Population density is the relation among the number of individuals of a population and the area or volume they occupy. For instance, in 2001 the hum

What is av block, Q. What is AV Block ? First Degree AV Block At ...

Q. What is AV Block ? First Degree AV Block At rest commonly disappears with exercise owing to the vagal withdrawal. The development of a prolonged PQ segment after exerc

Antiparkinsonian drugs, Antiparkinsmian Drugs: Antiparkinsonian drugs ...

Antiparkinsmian Drugs: Antiparkinsonian drugs are  the  specific drugs  to treat the extrapynnidal side effects  of  antipsychotic agents.  Anticholinergic drugs  block

Define causes of vitamin a deficiency - inadequate diet, Define Causes of V...

Define Causes of Vitamin A Deficiency - Inadequate diet? A child is born with poor stores of vitamins and minerals due to maternal malnutrition. Diets of pregnant women are def

Bottleneck for external sources for health care, Bottleneck for External So...

Bottleneck for External Sources for Health Care The implementation bottlenecks arising out of funding by external sources have important implications for the resource allocati

Explain about the connecting models and data, Explain about the Connecting ...

Explain about the Connecting models and data? Perhaps the most dramatic change in quantitative environmental biology in recent years has been the burgeoning progress in the dir

Objectives of psychological components, Objectives of psychological compon...

Objectives of psychological components It is essential to have objective scores, in order to identify and classify deficits in psychological components and processes. The nee

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