Sporophytic incompatibility, Biology

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.

Posted Date: 1/23/2013 5:23:49 AM | Location : United States







Related Discussions:- Sporophytic incompatibility, Assignment Help, Ask Question on Sporophytic incompatibility, Get Answer, Expert's Help, Sporophytic incompatibility Discussions

Write discussion on Sporophytic incompatibility
Your posts are moderated
Related Questions
A 'rag doll' seed tester Fold a square metre of muslin twice in the similar direction. Near one end mark out eight or ten squares about 5 cm by 5cm with a pencil. Number the sq

How dynamic biological processes represented as network? Many dynamic biological processes throughout a wide range of ecological scales are easily represented as dynamical netw

How is hydration control by active pump mechanisms responsible in the corneal hydration? Hydration Control by Active Pump Mechanisms: a) Na/K ATPase pump, which is more acti

What is d excretory organ of the agama lizard

Define Citrate Utilization Test - imvic test? Several microorganisms have the ability to make use of citrate as the sole source of carbon and energy. This ability relies on the

Pulp Tissue Revascularization :   Definition: Is the procedure to re-establish the vitality in non-vital tooth by allowing repair & regeneration of the tissues.

HISTORY OF THE CELL Term "Cytology" was given by Hertwig , he also wrote a book on " Cell and Tissue ". Father of cytology = Robert Hooke. Father of Modern cytology

Q. What are the modes of transmission, main signs and symptoms and treatments of hepatitis A? The Hepatitis A is an acute disease of low mortality caused by the hepatitis A vir

How is the body of gastropods divided? The body of gastropods is separated into three main portions: a) Head, b) The visceral mass and c) Foot.

Explain antimicrobial susceptibility All isolates of M. tuberculosis  should be tested for antimicrobial susceptibility. Initial therapy for most patients with active TB should