Rejection reaction, Biology

Assignment Help:

Rejection Reaction

For rejection reaction the physiological and biochemical processes are set in the pistil by the recognition reaction specific to the type of pollen that lands on stigma. In contrast to systems where inhibition can occur on stigma itself thus preventing germination of pollen or its entry into style, in GSI system it may occur in style leading to either inhibition of pollen tube growth or its bursting.

The pollen wall and its protein content plays an important role in pollen stigma interaction. Through cytochemical studies it has been observed that the pollen wall is perforated by protoplasmic strands giving the appearance of a living physiological structure playing a very responsible role in the process of interchange between the pollen grain and the substrate. The incorporation of proteinaceous substances in the exine and the intine has been demonstrated by EM studies of the pollen wall during development. A good amount of mobile proteins of the pollen grains is S-gene specific. The recognition proteins of incompatibility are held extra-cellularly in the pollen wall. In GSI plants, these proteins are present in the intine while in SSI plants they occur in the exine.


Related Discussions:- Rejection reaction

What is echocardiography, Q. What is Echocardiography? Ans. Echoca...

Q. What is Echocardiography? Ans. Echocardiography has become an established and powerful tool for diagnosing presence of CAD and defining its consequence. It can help in

What is the fluid that fills the nucleus called, Q. What is the fluid that ...

Q. What is the fluid that fills the nucleus called? The aqueous fluid that fills the nuclear region is called nucleoplasm or karyolymph. In the fluid there are enzymes, protein

Production of disease-free plants, Production of Disease-free Plants U...

Production of Disease-free Plants Under normal conditions plants are infected by a wide range of pathogens such as bacteria, fungi, viruses, viroids, and insects like nematode

Factors affecting normal blood sugar levels, Q. Factors Affecting Normal Bl...

Q. Factors Affecting Normal Blood Sugar Levels? Earlier in our discussion, we learnt that insulin is the most important factor responsible for normal blood sugar levels. Now we

Explain about pre - diabetes, Q. Explain about Pre - Diabetes? Pre - Di...

Q. Explain about Pre - Diabetes? Pre - Diabetes is a condition where blood sugar level is above normal but below to be diagnosed as diabetes mellitus. It has been found that

Nitrogen cycle, Nitrogen is very important constituents of all organisms li...

Nitrogen is very important constituents of all organisms life  because it forms the structural parth of proteins, nucleic acids and chlorophyll molecules.               Earth 's

Describe the structure of lipoprotein, There are several different lipoprot...

There are several different lipoprotein species found in plasma but their basic structures are similar. The insoluble lipid (cholesterol ester and triglyceride) forms a central cor

Name of structures you would expect to find in the dermis, Name of the stru...

Name of the structures you would expect to find in the dermis. In the dermis you would expect to search sensory nerve endings, nerve fibres, capillaries, arterioles and venules

Ciliary and flagellar movements, Normal 0 false false false...

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

What is fermentation, What is fermentation? Name any two organic compounds ...

What is fermentation? Name any two organic compounds formed in this process

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