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

Orthopedics, 1. List alternative therapies for musculoskeletal problems. ...

1. List alternative therapies for musculoskeletal problems. 2. What is a xyrospasm? What is the Greek derivative of the word? 3. Name and describe the three types of varus con

Explain wild-type fruitfly drosophila melanogaster, A cross among wild-type...

A cross among wild-type fruitfly Drosophila melanogaster  [normal bristles and grey body (s+s, e+ e)] with a mutant fly [short bristles and ebony body (ss ee)] produces following p

West nile virus infection, West Nile virus infection West Nile virus (W...

West Nile virus infection West Nile virus (WNV) is a type strain of flaviviruses and is related to Japanese encephalitis group. The virus was first isolated from a woman in the

Nursing responsibilities while administering immunization, NURSING RESPONSI...

NURSING RESPONSIBILITIES WHILE ADMINISTERING IMMUNIZATION Use one sterile syringe and needle for each injection.  Use only the diluent supplied along with measles and

Explain creaming volume formulae - performance evaluation, Performance Eval...

Performance Evaluation Cake batter aeration can be affected by the plasticity, consistency, emulsification, bake stock formulation and other fats and oil properties.  Creamin

Membrane carbohydrate, The  extracellular   surface  of  the  plasma  membr...

The  extracellular   surface  of  the  plasma  membrane   is  frequently  covered  with  a protective  coat  of carbohydrate. A Sugar  residue  of this  carbohydrate  coat can  be

What are heterotrophic beings, What are autotrophic beings? What are hetero...

What are autotrophic beings? What are heterotrophic beings? Autotrophic beings are those that can make their own food, i.e., that make organic material from inorganic compound

Non-renewable energy sources, In many countries of Asia biomass contributes...

In many countries of Asia biomass contributes l argely as a source of primary energy. People in rural areas at the peripheries of forests, continue to collect fuel wood from adjace

#titleclasses of fish.., what are the two main classes into which fish are ...

what are the two main classes into which fish are divided

Neurulation in amphibians, Neurulation in Amphibians The first step i...

Neurulation in Amphibians The first step in the neurulation process is the flattening and thickening of dorsal ectoderm to form neural plate. The plate of cells are different

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