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

#titlemicrobiology.., topics relating research on microorganisms and their ...

topics relating research on microorganisms and their application ?

Ecosystem, what is the main excretory organ of a lizard

what is the main excretory organ of a lizard

Do you know what the recommendations for fibre are, Do you know what the re...

Do you know what the recommendations for fibre are? Well, the crude fibre intake should be 14 g/1000 Kcal. For adult woman 25 g/day and for adult man 38 g/day is desirable.

Define anaemia in pregnancy, Define Anaemia in Pregnancy? Anaemia is th...

Define Anaemia in Pregnancy? Anaemia is the most common complication and is often compounded by low socio- economic status. However, it is seen frequently in upper income women

State the versions of binocular movements, State the Versions of Binocular ...

State the Versions of Binocular movements Versions are movements of both eyes in the same direction. a) Dextroversions: Movements of both eyes to'the right side. b) Levov

Ingestion of foreign bodies, Ingestion of Foreign Bodies: As we know  ...

Ingestion of Foreign Bodies: As we know  that small children are curious and  innocence children are notorious for inserting various object into their orifices like mouth, nos

Biodiversity and economics, With the survival and well-being of humans bein...

With the survival and well-being of humans beings so heavily dependent on biodiversity, its economic value assumes considerable importance. For instance the economic value of ecosy

photosynthesis: light energy to synthesize , Photosynthesis happens in alg...

Photosynthesis happens in algae, green plants and photosynthetic bacteria. Its part is to catch solar energy and use this to drive the synthesis of carbohydrate from water and carb

Define about the excretion of calcium, Define about the Excretion of Calciu...

Define about the Excretion of Calcium? Calcium is excreted approximately in equal amounts in urine and through intestinal secretions. Bile and other secretions into the intest

What is the clitellum of earthtworms, Q. What is the clitellum of earthtwor...

Q. What is the clitellum of earthtworms and where it is located? The clitellum is a special region of the annelid constituted by rings (metameres) with reproductive function. 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