Sporophytic incompatibility, Biology

Assignment Help:

Sporophytic Incompatibility

The recognition and rejection reactions in a SSI system occur on the stigma surface, placing barriers for pollen germination or penetration of pollen tube into the stigma. Thus the pollen grains either fail to germinate or the small tube they put out is inhibited by callose deposition at the tip. The papillae at the stigma also develop a lenticular callose plug within 10 min after pollination. Infact, in incompatible cases, inhibition of varying degrees operates at every level starting from pollen adhesion, hydration, germination and tube entry into the stigma. In some plants stigma is covered with a cuticular layer such that the incompatible pollen tube fails to penetrate.

Various studies have proved the necessity of enzyme cutinase in eroding the cuticle. This enzyme is activated only by the compatible cases. Incompatible stigmas may lack copious exudate, but dry stigmas have a hydrated layer called pellicle over the cuticle. This pellicle consists of a lipid layer where a mosaic of proteins floats. The pellicle probably originates by the protrusion on the surface of the papillae through discontinuities in the cuticle. As soon as pollen is received by the stigmatic surface the papillate cells exude moisture. The incompatibility is the result of interaction between protein fractions of exine and stigma.


Related Discussions:- Sporophytic incompatibility

Domestication - wildlife, Domestication - Wildlife It means that man h...

Domestication - Wildlife It means that man has taken under his direct care the living beings which are useful to him. Through extensive breeding programmes, he has modified th

Explain the importance the relationship of structure, Explain the importanc...

Explain the importance of understanding the relationship between structure and function?

#ti ZOOLOGY , WHAT ARE SOME INFORMATION ABOUT HUMAN ZOOLOGY?

WHAT ARE SOME INFORMATION ABOUT HUMAN ZOOLOGY?

Can you explain about krebs cycle, Q. Why can it be said that each glucose ...

Q. Why can it be said that each glucose molecule runs the Krebs cycle twice? Each glucose molecule "cycles" the Krebs cycle twice because after glycolysis each used glucose has

Explain micronutrient, Which one of the following is not a micronutrient? ...

Which one of the following is not a micronutrient? 1. Molybdenum 2. Magnesium 3. Zinc 4. Boron. Magnesium

Work injuries based on type of accidents, Work Injuries Based On Type of Ac...

Work Injuries Based On Type of Accidents Earlier we identified four kinds of injuries mainly based upon type of disability. This classification is needed for the purposes of c

Why are shapes of squamous cells different, How do the cheek and onion cell...

How do the cheek and onion cells visually resemble one another, and why are shapes of squamous cells so different than the onion cells?

Photolithoautotrophs - nutritional types of microorganisms, Explain Photoli...

Explain Photolithoautotrophs - Nutritional Types of Microorganisms? These microorganisms use light as an energy source, inorganic substance as electron source and CO 2 as the

A protein is normally found inside of a lipid bilayer, A protein is normall...

A protein is normally found completely within the inside of a lipid bilayer. The protein likely has: a) Mostly hydrophobic side chains, pointed outwards, with the peptide backbo

Explain endocarditis, Explain Endocarditis The risk of endocarditis is ...

Explain Endocarditis The risk of endocarditis is considered high in patients with last bacterial endocarditis, prosthetic heart valves, complex cyanotic congenital heart diseas

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