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

What is phospholipids, What is Phospholipids ? Phospholipids :  Ph...

What is Phospholipids ? Phospholipids :  Phospholipids are similar to triglycerides, except that they contain only two fatty acid, and one or both of the fatty acids have

Can you explain coronary angioplasty, Q. Can you explain Coronary Angioplas...

Q. Can you explain Coronary Angioplasty? The concept of coronary angioplasty - enlargement of the lumen of a stenotic vessel by a catheter technique was first proposed by Dotte

Describe the complex spatial patterns of biodiversity, Q. Describe the comp...

Q. Describe the complex spatial patterns of biodiversity? To describe the complex spatial patterns of biodiversity, ecologists and biogeographers have found it useful to expres

What is the difference between catabolism and anabolism, Q What is the diff...

Q What is the difference between catabolism and anabolism? Metabolism comprises two opposing processes: catabolism and anabolism. Anabolism is a set of synthesis reactions that

Define direct visualisation of coronary arteries, Q. Define Direct Visualis...

Q. Define Direct Visualisation of Coronary Arteries? Ans. Coronary arteries cad be directly visualized using two-dimensional echocardiography, especially in patients with

What are taenias and diseases caused by them, Q. What are taenias? What are...

Q. What are taenias? What are the diseases caused by them? The Taenias, as well know as tapeworms, are platyhelminth animals (flatworms). The major diseases caused by taenias a

Zoology, differences regarding Tiger Planaria and the Iridescent Phyllodoce...

differences regarding Tiger Planaria and the Iridescent Phyllodoce

Determine the chance of developing cancer, A typical chest x-ray exposes th...

A typical chest x-ray exposes the patient to a radiation dose of 0.01 rem. If a man receives 10 such x-rays in a lifetime, what is his chance of developing cancer as a result of th

What is the gross primary production of an ecosystem, What is the gross pri...

What is the gross primary production of an ecosystem? How does GPP relate to photosynthesis? Gross primary production of an ecosystem, or GPP, is the amount of organic material

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