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

Write the factorson on which metaboilc changes depend, The metaboilc change...

The metaboilc changes would depend on the  following  factors: a)  Nature of infection b)  Severity of the infection c)  Duration of the infection d)  Presence or abse

Hmp shunt in erythrocytes, HMP shunt in erythrocytes HMP shunt in eryth...

HMP shunt in erythrocytes HMP shunt in erythrocytes is of importance due to the generation of NADPH, which maintains the glutathione (G-SH)  in  the reduced  state by  glutathi

Sickle cell, Sickle cell anaemia in man is caused by a defective chain of h...

Sickle cell anaemia in man is caused by a defective chain of haemoglobin. The abnormal haemoglobin known as MbS differs from natural haemoglobin (HhA) in one amino acid. A substitu

What the enzymes do to reaction, What do enzymes do to a reaction? Indicate...

What do enzymes do to a reaction? Indicate all that are correct. a. Lower the activation energy b. Reverse the equilibrium c. Lower the equilibrium d. Increase the reac

Contact osteogenesis, Contact Osteogenesis: In this the osteogenic cells at...

Contact Osteogenesis: In this the osteogenic cells attach to the implant surface and the new (de novo) bone is formed on the implant surface first. The developing bone matrix can d

Why and how does the food get spoiled, Why and how does the food get spoile...

Why and how does the food get spoiled? There are several causes of food spoilage. These include: Growth of Microorganisms, such as bacteria, molds and yeasts, which can

Zoology, #question.characteristics of coelenterata?.

#question.characteristics of coelenterata?.

Kind of tetrasporic embruo sac, what are the kinds of tetrasporic embryo sa...

what are the kinds of tetrasporic embryo sac...detail information

Biosynthesis of hemes and chlorophylls, In animals, some of bacteria and fu...

In animals, some of bacteria and fungi, and the first step in tetrapyrrole synthesis is the condensation of the amino acid glycine with succinyl  CoA (an intermediate  of the citri

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