Central cell - synergids, Biology

Central Cell - Synergids

It is the largest cell of the embryo sac, and the mother cell of the endosperm. The enlargement of the embryo sac after the last nuclear division is mainly due to the inflation of the large central vacuole of the central cell. The vacuole in the central cell is presumably the reservoir of sugars, amino acids and inorganic salts. The nuclei of the central cell, also called the polar nuclei, are very large, and are characterized by a conspicuous nucleolus. They are present either in the centre of the cell, suspended by cytoplasmic strands, or in the cytoplasm close to the egg apparatus. In the latter case the chalazal portion of the embryo sac is occupied by a large vacuole. The two polar nuclei fuse before or during double fertilization to form the secondary nucleus.

The cytoplasm of the central cell is rich in plastids, mitochondria, numerous, dictyosomes, and ribosomes or small polysomes. This cell appears to be the centre of intensive synthetic activity in the embryo sac. The thickness of the central cell wall is variable. It is thickest in the regions in contact with the nucellus. Where the central cell touches the egg and synergids, it shows the common feature of partial wall. It becomes thinner towards the chalazal end of the egg apparatus, and finally, in the chalazal region there is no wall between the plasma membranes of the central cell and those of the egg and the synergids. The central cell is connected along with the.egg, synergids, and the antipodals through plasmodesmata connections.

Posted Date: 1/23/2013 2:01:22 AM | Location : United States







Related Discussions:- Central cell - synergids, Assignment Help, Ask Question on Central cell - synergids, Get Answer, Expert's Help, Central cell - synergids Discussions

Write discussion on Central cell - synergids
Your posts are moderated
Related Questions
Define the Flavonoids? Flavonoids constitute the largest group of plan1 polyphenols, generally arc the compounds of low molecular weight, bound to sugar molecules. You may be f

Define Nutritional Requirements for Extreme Environments? Human beings have been able to survive and work under extreme environments of almost all regions of the earth, from po

What are the main diseases caused by errors of the number of sex chromosomes in the cells of an individual? Diseases caused by the abnormal number of sex chromosomes are called

classification of grantia

Define Proteins as Structural Elements and Structural Units? The liver cell membrane analysis shows that this membrane contains 50-60% protein, 35% lipids and 5% carbohydrates.

Define the term Prebiotics? Dietary Sources and their Mode of Action/health Effects We have already seen how prebiotics are defined. Let us go a little in-depth about them. Pre

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

Write down any other possible explanations you think of.could the cooler have had any effect? Could something in the water be reasonable? Could there be an object in the water that

Q. How does sexual reproduction take place in bacteria? How dissimilar are the modalities of bacterial sexual reproduction? Sexual reproduction occurs when bacteria incorporate

Define Fluconazole It is a weaker inhibitor of CYP3A4 than itraconazole or ketoconazole but may still increase serum concentrations of drugs metabolized by 3A4, like cyclospor