Pollen tube growth, Biology

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.

Posted Date: 1/23/2013 4:31:18 AM | Location : United States







Related Discussions:- Pollen tube growth, Assignment Help, Ask Question on Pollen tube growth, Get Answer, Expert's Help, Pollen tube growth Discussions

Write discussion on Pollen tube growth
Your posts are moderated
Related Questions
Q. What is the difference between diabetes mellitus and diabetes insipidus? What are the characteristic signs of diabetes insipidus? Diabetes mellitus is the disease caused by

Bovine parainfluenza This virus belongs to the genus Respirovirus in the subfamily Paramyxovirinae of family Paramyxoviridae. It causes respiratory syndrome in cattle and shee

What are the main degenerative diseases of the heart? The major degenerative diseases of the heart are heart failure, arrhythmias, valvular heart diseases, coronary insufficie

Q. Under which form is nitrogen fixed by living beings? The Most living beings can't use molecular nitrogen to obtain nitrogen atoms. The Producers fix nitrogen primarily from

Signify the term - Trachea Part of the respiratory system in insects, vertebrates and some spiders. In invertebrates it comprise tubules carrying air directly from outside to t

In a chemical reaction the free energy change (/\Go') is -40 jk/mol and the entropy factor T/\S is 15 kj/mol. the enthalpy change /\H for the reaction is a. 25 kj/mol b.-25 k

Bacteria, mutations, recombination, evolution, and adaption, how are all these related; must be written in two sentences.

Define About the Sterols - Non Glyceride Fractions? These constitule a major proportion of the non-glyceride component while tocopherols, carotene pigments and flavour compound

a precaution to follow when heat fixing a smear

I need help with p-p, q-q and r-r intervals and heart rates