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

Pumps, The pumps The blood from the operating field is sucked with t...

The pumps The blood from the operating field is sucked with the help of the cardiotomy sucker and pump, which is filtered to remove all particulate matter and then pass

Nursing assessment of acute glomerulonephritis, Nursing Assessment   Du...

Nursing Assessment   During assessment the child's parents will give you history of upper respiratory infection or skin infection  in the previous one to three weeks. Initially

Describe the clinical evaluation mvp murmur in details, Describe the Clinic...

Describe the Clinical Evaluation MVP Murmur in details? Characteristic: Mid systolic click followed by a late systolic murmur which usually extends to A2. The click may be abse

Objective of nutrient needs during periods of pregnancy, Define Objective o...

Define Objective of nutrient needs during periods of pregnancy? describe the various physiological changes during pregnancy, describe foetal growth and development and

Stress - responses of plants to stress, Stress - Responses of Plants to Str...

Stress - Responses of Plants to Stress Let us recall what happens within the natural communities occupying the same habitat. The relative location of two plants may place them

Major cell types that form the osseous tissue, Q. What are the three major ...

Q. What are the three major cell types that form the osseous tissue? What are their functions? The three major cell types of the osseous tissue are the osteocytes, the osteobla

Heart in amphibians, Amphibia n - 3 chambered heart 2 auricles and ...

Amphibia n - 3 chambered heart 2 auricles and 1 ventricle. Sinus venosus and truncus arteriosus (its main part is pylengium) present. Incomplete double circulation prese

Define affluence availability of food as factor for obesity, Define Affluen...

Define Affluence and abundant availability of food as factor for obesity? With increasing affluence, increase in purchasing power and abundance of food, people tend to eat more

Function of cholecystokin in the digestive process, Q.How is it produced an...

Q.How is it produced and what is the function of cholecystokin in the digestive process? The fat level of the chyme detected in the duodenum stimulates the secretion of cholecy

Define behaviour modification - combat from obesity problem, Define Behavio...

Define Behaviour modification - combat from obesity Problem? It is very important. A heavy parental hand and parent attitude and behaviours towards child's eating, interferes i

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