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

Why does the urinary volume increase, Why does the urinary volume increase ...

Why does the urinary volume increase when alcoholic beverages are ingested? Alcohol inhibits the ADH (antidiuretic hormone) secretion by the hypophysis. Low ADH decreases the t

Nerve impulse, NE R VE IMPULSE (IT'S GENERATION) - It is an electr...

NE R VE IMPULSE (IT'S GENERATION) - It is an electro chemical phenomenon manifested through ionic movement across cell membrane. It was discovered by A. L. Hodykin & A

Scientific american article suggests some improvement, The human skeleton h...

The human skeleton has evolved from that of four-legged animals. Unfortunately, the adaptation is far from perfect; thus, our upright posture causes problems like back age and the

Demonstrate the structure of mitochondria, Demonstrate the structure of mit...

Demonstrate the structure of mitochondria The structure of mitochondria has been examined in great detail with the aid of the electron microscope, and it is now possible to des

Concentration Gradients and Membrane Permeability, 3. Which substance(s) cr...

3. Which substance(s) crossed the dialysis membrane? Support your response with data-based evidence.

Human impact on enviroment, What are the principal sources of of excessive ...

What are the principal sources of of excessive nitrate and phosphatebin rivers and lakes?

What are the different organs of the respiratory system, The different orga...

The different organs of the respiratory system  Nostrils through which we inhale air in the nasal cavity  Pharynx  Larynx  Trachea (wind pipe)  Lungs - Bronchi,

Explain the role of cuvier in animal taxonomy, Explain the role of cuvier i...

Explain the role of cuvier in animal taxonomy? Cuvier (1769-1832) was critical of Lamarck's evolutionary concept which thereafter remained in oblivion for half a century. Cuvi

Define nervous system and the it's related disorders, Define Nervous System...

Define Nervous System and the it's related disorders? In this unit, we learnt about nervous system and the related disorders, which are termed as 'neurological disorders'. Neur

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