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

Define aerobic exercise or aerobic energy system, Define Aerobic Exercise o...

Define Aerobic Exercise or Aerobic Energy System? To produce necessary energy, the body uses an aerobic pathway and an anaerobic pathway. Exercise that relies heavily on oxygen

Describe nerve cells, In eukaryotes possibly the most rapid and complex sig...

In eukaryotes possibly the most rapid and complex signaling is mediated through nerve impulses.  The Nerve  cells  (neurons)  consist  of  a cell  body  with  numerous projections

Ecology, Importance of ecology

Importance of ecology

Experiment of stanley miller (1953) on the origin of life, What was the exp...

What was the experiment of Stanley Miller (1953) on the origin of life? In 1953 the Stanley Miller arranged an experimental apparatus that simulated the atmospheric conditions

Determine the basic seven food groups - nutritions, Determine the Basic Sev...

Determine the Basic Seven Food Groups - Nutritions? These basic seven food groups are: 1) Cereals and cereal products 2) Pulses (also meat and meat products) 3) Milk and m

Use of alternate metabolic pathways, Use of Alternate Metabolic Pathways ...

Use of Alternate Metabolic Pathways Plants surviving under water-logged conditions offer the simplest example of such a response. The submerged parts of such plants use the an

Plant physiology, what is the importance of lignin in xylem formation

what is the importance of lignin in xylem formation

How does phosphorus cycle vary from carbon cycle, (a) Trace the succession ...

(a) Trace the succession of plants on a dry bare rock. (b) How does phosphorus cycle vary from carbon cycle?

Show the value of embryology, Q. Show the value of embryology? The valu...

Q. Show the value of embryology? The value of embryology in solving taxonomic problems can be appreciated by studying some specific cases. Amongst the classical examples cited

Explain elastic fibers would not wrinkle, As we age, our skin wrinkles due ...

As we age, our skin wrinkles due to change in collagen and elastic fibers in the dermis and a decrease in their production. Explain why topical application of collagen and elastic

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