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 irradiation, Explain Irradiation The physical process of expos...

Explain Irradiation The physical process of exposing an object, system, or a material to a high radiant energy for the sterilization or preservation.

What is the absolute pressure at the bottom of the container, A container i...

A container is filled to a depth of 20.0 cm with water. On top of the water floats a 30.0-cm-thick layer of oil with specific gravity 0.700. What is the absolute pressure at the bo

What are the symptoms of pectic ulcer, Q. What are the Symptoms of pectic u...

Q. What are the Symptoms of pectic ulcer? Increased gastric tone and painful hunger contraction when stomach is empty. Hunger contraction 1-3 hours after meals is the main com

What are the three main parts of a eukaryotic cell, Q. What are the three m...

Q. What are the three main parts of a eukaryotic cell? The eukaryotic cell can be separated into two major portions: the cell membrane that separates the intracellular space fr

Extravascular compression, Most of the coronary blood flow to the left vent...

Most of the coronary blood flow to the left ventricular myocardium occurs during diastole. Thus the contracting heart obstructs its own blood supply. The systolic compressive force

Agro industrial-zinc, Zinc Zinc regulates over a dozen important enzym...

Zinc Zinc regulates over a dozen important enzyme systems involved in metabolism of protein and carbohydrates. Zinc is also required for maintaining responsiveness of the immu

What is sarcoplasmic reticulum, An increase in the calcium conductance of a...

An increase in the calcium conductance of all sarcoplasmic reticulum membranes of a skeletal muscle with no external forces on it leads to A. an increase in the amount of calci

Grazing food chain - food chain, Grazing Food Chain - Food Chain Grazi...

Grazing Food Chain - Food Chain Grazing food chains are quite familiar to most of us. Cow or deer grazing in a field represent a grazing food chain. Similarly, eating of phyto

Signs and symptoms of emphysema, Pathophysiology Distension and damage...

Pathophysiology Distension and damage of the respiratory bronchioles selectively occur. Opening develops in the walls of the bronchioles. and they become enlarged and conf

How can the reactions of the nervous system be classified, Q. Concerning vo...

Q. Concerning volition of the individual how can the reactions of the nervous system be classified? The efferences (reactions) of the nervous system can be classified into volu

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