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

Complement system, Complement system is a chemical defense system which ki...

Complement system is a chemical defense system which kills the microorganisms directly, it supplements inflammatory response, and works with, or complements, the immune system.

Ecological adaptation in animals to aquatic environment, Ecological adaptat...

Ecological adaptation in animals to aquatic environment In the aquatic environment animals are confronted with the problem of excess water. Freshwater and marine animals try to

Bro cheese, so bro how do get rid of my bro cheese coz that bro stinks

so bro how do get rid of my bro cheese coz that bro stinks

Comparison to healthy lungs, The nature of the sounds produced by percussio...

The nature of the sounds produced by percussion (tapping) a patient's chest can tell a physician a great deal about the condition of the organs within the thoracic cavity. Healthy,

Coronary arteries, Coronary Arteries The right coronary artery origina...

Coronary Arteries The right coronary artery originates form the right aortic valvular cusp, its, SA nodal branch supplies the SA node and AV nodal branch supply the AV nod

What is the meaning of darwins expression, What is the meaning of Darwin's ...

What is the meaning of Darwin's expression "descent with modification"? Descent with modification refers to natural selection. Descent with modification refers to evolutionary chan

Define the theory or principle of drying, Define the Theory or Principle of...

Define the Theory or Principle of Drying? Drying can be illustrated as the application of heat under controlled conditions to eliminate the majority of the water generally avai

Protozoan slides, Protozoans are a group of animal protists of more than 50...

Protozoans are a group of animal protists of more than 50,000 species and are found under almost all natural conditions where there is moisture. A protozoa11 is not as simple an or

What are the major representatives of the pteridophytes, Q. What are the ma...

Q. What are the major representatives of the pteridophytes? Is this plant group phanerogamic or cryptogamic? The better known pteridophytes are the ferns and the maidenhairs, f

What structural features do these organisms, What STRUCTURAL features do th...

What STRUCTURAL features do these three organisms have in common in terms of a) excretory systems b) respiratory systems c) circulatory systems and d) nervous systems ? The species

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