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

State the classification of nervous system, State the Classification of ner...

State the Classification of nervous system Neurological disorders can be categorised according to the primary location affected, the primary type of dysfunction involved, or th

Determine recommended nutrient intakes by selenium, Determine recommended n...

Determine recommended nutrient intakes by selenium? The FAO/WHO 2004 recommendation for nutrient intake for selenium by groups is given in Table. How do these recommendations c

Role of dietitian in health care, Role of Dietitian in Health Care The ...

Role of Dietitian in Health Care The role of the dietitian has come a long way since the early 1900s. Their role is still unknown to a  lot of people. Some think that dietitian

Homopolysaccharides, HOMOPO L YSACCHARIDE S (= HOMOGLYCANS) These...

HOMOPO L YSACCHARIDE S (= HOMOGLYCANS) These are complex carbohydrats that are formed by repeated condensation or polymerisation of only one type of monosaccharide monome

Mechanisms that affect the heart rate, Mechanisms that Affect the Heart Rat...

Mechanisms that Affect the Heart Rate Two different mechanisms affect the heart rate. Nerve impulse to the pacemaker region and hormonal influences. A branch of the vagues ner

How many times acidic is a ph=4, How many times more acidic is a pH=4 from ...

How many times more acidic is a pH=4 from a pH=7 solution?

Thyroid gland, THYROID GLAND - It develops from the endoderm of the ...

THYROID GLAND - It develops from the endoderm of the embryo. Th e thyroid gland is the largest endocrine gland located anterior to the thyroid cartilage of the larynx

What is bilateral symmetry system, What is Bilateral Symmetry system? T...

What is Bilateral Symmetry system? To review: all animals besides the sponges (Phylum Porifera) belong to the Eumetazoa. There are two groups within the Eumetazoa that possess

Explain the management of eating disorders, Explain the Management of Eatin...

Explain the Management of Eating Disorders? We shall consider the components of the management of anorexia nervosa and bulimia nervosa together, since the nutritional consequen

Explain submarginal curved - limited mucoperiosteal flaps, Explain Submargi...

Explain Submarginal Curved - Limited Mucoperiosteal Flaps - Also called: semilunar flap, - Curved incision in the alveolar mucosa and the attached gingival. - NO advantag

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