Passage of pollen tube, Biology

Passage of Pollen Tube

In cotton, the pollen produces a tube within an hour which grows on the surface of the stigmatic hairs, and then between the cells of the stigma at the bases of hairs and beyond. The cytoplasm of the stigmatic hair degenerates; no exudate is secreted. The tube continues growth through the intercellular spaces of the thin-walled cells of transmitting tissue. After reaching the thick-walled cells of the main strand, it actually grows through wall layer 3. It has been reported that pollen tube of Petunia grows within the compact matrix of the middle lamella of the transmitting tissue by enzymatically creating a pipe-like path in front. By the increased dictyosome activity the cells become thicker. Callose is deposited in the pit fields on the transmitting tissue after the passage of pollen tube.

The pollen tube passage probably changes the permeability of cells and callose is formed as a wound response and as a reaction against cell leakage. Once the pollen germinates and the pollen tube has penetrated the stigmatic tissue, the path of the pollen tube through the rest of the stigma and style appears to be determined by the nature and structure of the cell walls and the morphology and distribution of the transmitting tissue. The nutritive role of the transmitting tissue was recognized early. Pollen tubes of Lilium, Petunia and Oenothera are shown to draw nourishment (sugar and amino acids) from the stylar tissue. Growth of tubes through style causes an increased inflow of carbohydrates into the pistils. In Aegle marmelos the cells surrounding the stylar canals show an optimal concentration of starch just before pollination, subsequently as the starch is digested, the canal cells and the basal portions of the stigmatic papillae show reducing sugars which also disappear within 3 days after pollination. Disappearance of stylar starch has also been observed in Fritillaria, Zephyranthes and Pavonia.

Posted Date: 1/23/2013 4:26:55 AM | Location : United States







Related Discussions:- Passage of pollen tube, Assignment Help, Ask Question on Passage of pollen tube, Get Answer, Expert's Help, Passage of pollen tube Discussions

Write discussion on Passage of pollen tube
Your posts are moderated
Related Questions
Need an essay in regard to an experiment that I did. Essay Assignment: Experimental Design Now that you have completed several hands-on lab experiments, take a little time to con

Cytokinesis It is defined  as the division or cleavage  of cytoplasmic  part   of the cells  into  two  daughter  cells. It is first  indicated   during  late  anaphase  by app

How do the cheek and onion cells visually resemble one another, and why are shapes of squamous cells so different than the onion cells?

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

How can the visual deficiencies known as myopia and hypermetropia be optically explained? Myopia is the visual condition in which the images are produced before (in front of)

Chlorine (Cl) - Micronutrients The role of Cl - in plant is not clearly understood. Cl - is required in Hill reaction, the water splitting reaction of photosystem II. In the

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

Q. Can you explain Coronary Angioplasty? The concept of coronary angioplasty - enlargement of the lumen of a stenotic vessel by a catheter technique was first proposed by Dotte

Physical map is the map of locations of the identifiable landmarks on DNA (for example restriction of the enzyme cutting sites, genes), regardless of their inheritance. Distance i

Better coal should have following characteristics (1)   It should have high calorific value. (2)   It should have low moisture content. (3)   It should have low ash  conte