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

Pisces, I have an assignment about Pisces in zology can you creat it

I have an assignment about Pisces in zology can you creat it

Metazoa, Metazoa In the two kingdom classification, the unicellular 'a...

Metazoa In the two kingdom classification, the unicellular 'animals' used to be clubbed together under a single phylum Protozoa that constituted sub-kingdom - Protozoa. The re

Define th technique - stage two using a mucoperiosteal flap, Stage two usin...

Stage two using a mucoperiosteal flap A Mid crestal incision over the implant site is made and reflection of mucoperisteal flap is done under local anesthesia. After locating t

Explain left ventricle enlargement, Q. Explain Left Ventricle Enlargement? ...

Q. Explain Left Ventricle Enlargement? The left ventricle (LV) is ellipsoid in shape. It lies behind, and to the left of the right ventricle. Its long axis lies at about 45 deg

Access cavity perforation - types of root perforation, Access Cavity Perfor...

Access Cavity Perforation - Types of Root Perforation Can occur during access cavity perforation (specially in anterior) Due to misdirection of bur during access cavit

What is plastids, What is Plastids? The most obvious difference between...

What is Plastids? The most obvious difference between plant cells and other eukaryotic cells is that cells of most plants contain unique organelles called plastids, which inclu

Explain fetal development, Explain Fetal Development? The medical profe...

Explain Fetal Development? The medical profession divides pregnancy into three-month stages called trimesters. At the end of the first trimester, the fetus is only about 5 cm l

Different types of ecosystem, An ecosystem is a self sufficient interacting...

An ecosystem is a self sufficient interacting system in the biosphere. Eg. forest, desert, pond etc. almost, all the ecosystem have more or less similar fundamental plan for their

Describe primitive anaerobic eukaryotic cells, Q. How can the hypothesis th...

Q. How can the hypothesis that asserts that chloroplasts as well as mitochondria were primitive prokaryotes that related in mutualism with primitive anaerobic eukaryotic cells be c

What is transportation of sick newborn infants-heart disease, What is Trans...

What is Transportation of Sick Newborn Infants with Heart Disease Communication : The decision to transport a newborn to a tertiay referral centre with facilities for specia

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