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

State the limitations of intra oral periapical radiographs, Limitations of ...

Limitations of Intra Oral Periapical Radiographs  It is not optimal in pre operative planning of cases with severely resorbed ridges  Anatomical structure of importance can'

Explain about homeostatic regulation, What is an example of negative feebac...

What is an example of negative feeback of the homeostatic regulation? Negative feedback happens when the response to a given action makes an effect that inhibits that action. F

What is the function of vitamin e, Q. What is the function of vitamin E? In...

Q. What is the function of vitamin E? In which foods can it be found? Vitamin E is also known as tocopherol is a fat-soluble vitamin that participates as coenzyme in the respir

Define the recommended dietary allowance for vitamin b12, Define the Recomm...

Define the Recommended Dietary Allowance for Vitamin B 12 (RDA)? Vitamin B 12 deficiency is common in true vegans who can be treated with small doses since the daily requirem

Active transport, Active Transport We have mentioned above that Transm...

Active Transport We have mentioned above that Transmembrane potential develops due to active transport of ions (H + ) outside the cell. Since this transport takes place again&

Termination and follow-up in diabetes mellitus, Q. Termination and Follow-u...

Q. Termination and Follow-up in diabetes mellitus? After plan is implemented, you have to assess the progress. Slowly start winding up the contact with the client and the famil

Explain about the deficiency of riboflavin, Explain about the Deficiency of...

Explain about the Deficiency of Riboflavin? Riboflavin deficiency results in the condition of hypo- or ariboflavinosis, with sore  throat, hyperaemia (condition in which the bl

Define the skin capillary fragility test, Define the Skin Capillary Fragili...

Define the Skin Capillary Fragility Test? One of the earliest signs of ascorbic acid deficiency is the fragility of the capillaries. Capillary fragility is measured by applyin

Define oven - nutritional biochemistry, Define Oven - Nutritional Biochemis...

Define Oven - Nutritional Biochemistry? Oven is a general term used to describe a chamber or enclosed compartment for heating, baking, or roasting food, as in a stove, or for f

How are the major classes of arthropods classified, Q. How are the major cl...

Q. How are the major classes of arthropods classified according to the presence of larval stage in their embryonic development? In crustaceans there are others with indirect an

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