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 the other name given to the sex chromosomes, Q What is the other na...

Q What is the other name given to the sex chromosomes? What is the function of the sex chromosomes? Sex chromosomes are also known as allosomes the other chromosomes that are n

Why is knowledge of chemistry necessary for study, Why is knowledge of chem...

Why is knowledge of chemistry necessary for the study of living organisms?

What is megalobastic anemia, Question 1) What is megalobastic anemia? Disc...

Question 1) What is megalobastic anemia? Discuss briefly its lab diagnosis. How would you differentiate megaloblastic anemia from other anemias? Question 2) What is hem

Why low ca++ in the body fluid cause in body, Low Ca ++ in the body fluid ...

Low Ca ++ in the body fluid may be the cause of: 1.  Tetany 2. Anaemia 3. Angina pectoris 4. Gout  Tetany cause low ca ++

How do genetic mutations influence biological diversity, How do genetic mut...

How do genetic mutations influence biological diversity? Too frequent or too extensive genetic mutations usually are deleterious for individuals and species. These mutations fr

Neo-zoonoses, Neo-zoonoses In recent times, some of the pre-existing l...

Neo-zoonoses In recent times, some of the pre-existing low profile and less frequent zoonoses and some entirely newly recognized zoonoses are emerging with a new dimension. Th

Gene targeting, Gene targeting: There is always a debate on gene integrat...

Gene targeting: There is always a debate on gene integration in to the host animal. It is random gene integration Vs gene targeting. Perhaps most significantly, pro-nuclear in

Explain digestion and of digestive system of platyhelminthes, Q What are th...

Q What are the kinds of digestion and of digestive system of platyhelminthes? Flatworms have incomplete digestive systems and they present intracellular and extracellular compl

Respiration, how do flatworm and round worms respire?

how do flatworm and round worms respire?

Geographic speciation, In almost all animal groups, the mode of speciation ...

In almost all animal groups, the mode of speciation is geographic speciation. It is essential that a population which is a prospective new species is geographically isolated from t

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