Gametophytic incompatibility, Biology

Assignment Help:

Gametophytic Incompatibility

In GSI systems callose deposition is not evident on the stigma but is very conspicuous in the pollen tube. Sometimes the callose deposition occurs even in the germpore, inhibiting pollen germination. In the Poaceae, the rejection reaction is completed within a few minutes after pollination and subsequent rejection or acceptance takes 10 minutes with the exception of Poaceae and Oenothera, the recognition/rejection reaction in GSI system occurs after the pollen tube has grown about two third the length of the style.

Genetically the recognition factor on the male side has been attributed to the male gametophyte; the proteins incorporated during pollen wall development in the intine are involved. Since in GSI systems the rejection reaction is comparatively delayed, is also possible that the synthesis or activation, and release of the recognition substances are also delayed and they occur in the pollen tube. In some species the tubes show reduced level of carbohydrates and starch.


Related Discussions:- Gametophytic incompatibility

Indications for surgery-pericardial diseases, Indications for Surgery :  O...

Indications for Surgery :  Once diagnosis of constrictive pericarditis is made and confirmed by chest X-ray, ECG, echocardiogram, CT, MRI scan, cardiac catheterisation and angio,

Areas affected in peptic ulcer, Q. Areas affected in peptic ulcer? The ...

Q. Areas affected in peptic ulcer? The areas affected in peptic ulcer (due to erosion) can be: 1. Lower part of the oesophagus. 2, stomach (lesser curvature - an urn, whe

Vertical stratification - tropical rain forest, Vertical Stratification - T...

Vertical Stratification - Tropical Rain Forest In a tropical rain forest, vertical stratification is very clearly seen. In addition to the different layers described above, th

Environment , Environment All organisms are intimately dependent on the ...

Environment All organisms are intimately dependent on the environment from which they derive their sustenance. Organisms from virus to man are obligatorily dependent on the envi

Phyletic lineage, Ask questiona brief assignment on it #Minimum 100 words a...

Ask questiona brief assignment on it #Minimum 100 words accepted#

Special property of a persistent insecticide, a) What is the special proper...

a) What is the special property of a 'persistent' insecticide? b) In what ways is 'persistence' (i) a useful property, (ii) a harmful property?   (a) A persisten

How simple transposition of the great arteries present, How Simple Transpos...

How Simple Transposition of the Great Arteries Present after 30 Days ? A switch operation will have poor results, as the ventricle that has regressed will not be able to mainta

Evolutionary changes in humans, Evolutionary changes that occurred in human...

Evolutionary changes that occurred in humans are - Development of prominent chin. Increase in cranial capacity. Reduction of brow-ridges. Development of speech. Developme

What are abiotic factors?, What are abiotic factors? The Abiotic factor...

What are abiotic factors? The Abiotic factors are the nonliving elements that constitute a given environment, like light, temperature, water, minerals, gases, atmospheric press

Zoology, Wheel organ of amphioxus.

Wheel organ of amphioxus.

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