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

Cancer, What is Cancer? Besides AIDS, Cancer is another deadly human di...

What is Cancer? Besides AIDS, Cancer is another deadly human disease of our times about which people are panicky all over the world. It is estimated that one in every three per

Define requirements of calcium during pregnancy period, Define requirements...

Define requirements of Calcium during pregnancy period? The foetus retains about 25-30 g of calcium, over the course of gestation, most of which is deposited in the last trimes

Name the source gland of leutinising hormone, Name the source gland of leut...

Name the source gland of leutinising hormone (LH). State the other hormone along with which it acts on its target cells/organ. Give their two functions.

How different are the respiration in fishes, How different are the respirat...

How different are the respiration in fishes and the respiration in adult amphibians? In fishes gas exchange is completed by direct contact of water with the branchiae (gills).

Discuss about troponin receptor site, Skeletal muscle A. The myosin hea...

Skeletal muscle A. The myosin head is activated (energized) by the conversion of GTP (that is bound to myosin) to GDP and Pi (that are bound to myosin). B. Detachment of the

Explain the term - muscle contraction headache, Explain the term - Muscle C...

Explain the term - Muscle Contraction Headache This is one of the most common headaches. It is also known as tension or nervous headaches. They result from sustained contractio

Immobilisation of cells, Immobilisation of cells Immobilisation of cel...

Immobilisation of cells Immobilisation of cells enables Re-use of biomass by rotation of cells Separation of cells from the medium and Leaching of metab

Platyhelminthes - regeneration in invertebrates, Platyhelminthes (Flatworms...

Platyhelminthes (Flatworms) - Regeneration in Invertebrates Between flatworms the turbellarians, (mostly fresh water species and fresh water and terrestrial triclads) routinel

Products of hemp plant, PRODUCT S OF HEMP PLANT - Four drugs - bhan...

PRODUCT S OF HEMP PLANT - Four drugs - bhang, ganja, charas & marijuana obtained from Cannabis indica and C. sativa of family Moraceae . Main alkaloid is tetrah

What is the functional importance of structural difference, The vertebral ...

The vertebral bodies are much larger in the lower back than the neck. What is the functional significance of this structural difference?

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