Pollen tube growth, Biology

Assignment Help:

Pollen Tube Growth

There are significant differences in the fine structure of the tips of pollen tubes in compatible and incompatible pistils such as Lilium. Tubes growing in compatible pistils show deep embayment but no compartments (tubes in incompatible pistil have a compartmented cap). The compatible tubes undergo a transition from autotrophic nutrition (characterized by compartmented cap of golgi derived vesicles) to heterotrophic condition in which the secretion product from the stylar canals enter the pollen tubes through the deep embayments (tubes growing in incompatible pistils are unable to make this transition and thus are unable to continue growth due to the exhaustion of endogenous food reserves).

The pollen tube wall is composed mainly of polysaccharides. Since the pollen grain carries limited food reserves and a relatively large amount of new pollen wall material is synthesized during growth, it has been assumed that at least a part of the substance needed for pollen tube wall is contributed from the polysaccharides present in the pistil tissues. It has been shown that the polysaccharide component of the stigmatic exudate of L. longiflorum is incorporated into the cytoplasm of the growing pollen tubes and later a specific fraction of the incorporated exudate is extensively metabolised before being utilized for pollen tube wall biosynthesis.


Related Discussions:- Pollen tube growth

Of which type of defense cell do worm infections, Q. Of which type of defen...

Q. Of which type of defense cell do worm infections stimulate the multiplication? The main leukocytes that generally participate and multiply in the defense against worm infect

Endocrine glands - liver, LIVE R - The liver produces a protein angiot...

LIVE R - The liver produces a protein angiotensinogen which is changed to angiotensin II by an enzyme renin secreted by the juxtaglomemlar apparatus of the nephrons in the kid

Show the difference between sperm and spermatids cells, Q. What is the diff...

Q. What is the difference between sperm and spermatids cells? What is the name of the transformation of spermatids into sperm cells? Sperm cells (the male gametes) are matured

State the term - infection, State the term - Infection Infection is th...

State the term - Infection Infection is the invasion of the body by disease-producing (pathogenic) microorganisms and the reaction of the tissues to their presence and to the

Phylum Protozoa, Make a detailed study on Phylum Protozoa taking an example...

Make a detailed study on Phylum Protozoa taking an example with clear labeled diagrams.

What is phylum hemichordata, What is Phylum Hemichordata ? The name "he...

What is Phylum Hemichordata ? The name "hemi"; (meaning "half") provides a clue to these animals, which have some of the features of chordates, and some features that are chara

What is normal bone physiology, What is normal bone physiology An insig...

What is normal bone physiology An insight into the normal bone physiology and its adaptation by modeling and remodelling process to functional stresses is also of importance. I

Morphological changes - floral induction, Morphological Changes - Floral In...

Morphological Changes - Floral Induction Some of the morphological changes that accompany floral induction are: Change in the shape of meristem, Increase in the ra

Determine the uses of electrical recording - brain function, Determine the ...

Determine the uses of Electrical Recording - Brain function We can also learn about brain function by recording its electrical activity. In electroencephalography (EEG) and the

Homeostais, what is homeostasis and how does it happen

what is homeostasis and how does it happen

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