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

What are the chemical bonds of the dna molecule, Q. What are the chemical b...

Q. What are the chemical bonds of the DNA molecule that are broken for replication process to occur? During the DNA replication process, hydrogen bonds between the nitrogen- co

Define the coenzyme activity of nicotinic acid, Define the Coenzyme activit...

Define the Coenzyme activity of nicotinic acid? Nicotinamide exists within the redox-active coenzymes,  nicotinamide adenine dinucleotide (NAD) and its phosphate (NADP), which

Nutrient requirements for preterm and low birth weight, Define the Nutrient...

Define the Nutrient requirements for preterm and low birth weight? Energy: For preterm infants 1.20 Kcal/kg/day,            For normal infants 108 Kcal/ kg/ day. Proteins

Dysrhythmias - complications of cardiac surgery, Dysrhythmias Usually ...

Dysrhythmias Usually occur during the initial 24-72 hours, but may occur later on also. The causes may be ventricular irritability due to manipulations of heart durin

Annelida, what are the unique characteristics of a flatworm

what are the unique characteristics of a flatworm

Describe excretory system of annelids, Q. How be able to the excretory syst...

Q. How be able to the excretory system of annelids be described? In each segment (metamere) of the being a pair of complete excretory structures known as metanephridium exists.

Explain the catabolic responses, Explain the Catabolic Responses? Hormo...

Explain the Catabolic Responses? Hormonal responses during the hyper inetabolic phase of infection are same as in case of injury. Serum cortisol levels are elevated, glycogen i

Why carbon monoxide considered inorganic compounds, Why are calcium carbona...

Why are calcium carbonate and carbon dioxide and carbon monoxide considered inorganic compounds? "The name "organic" is a historical name, dating back to 19th century, when it

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