Central cell - synergids, Biology

Assignment Help:

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.


Related Discussions:- Central cell - synergids

Define effect of protein excess during pregnancy period, Define effect of P...

Define effect of Protein excess during pregnancy period? It is not advisable to recommend protein supplements. Reports in the literature indicate that high-protein supplements

Pericardium, The heart is enclosed in a membranous sac called the pericardi...

The heart is enclosed in a membranous sac called the pericardium. It has two layers- the fibrous pericardium which is the outer layer and the serous pericardium that lies inside th

Explain changes in body tissue compartments - underweight, Explain the Chan...

Explain the Changes in Body Tissue Compartments - Underweight? The severity of nutritional deprivation determines the extent of changes in the body tissue compartments. The fir

Photosynthesis, how does the green plant build up carbohydrates

how does the green plant build up carbohydrates

What are biotic factors, What are biotic factors? The Biotic factors ar...

What are biotic factors? The Biotic factors are living beings (plants, microorganisms and animals) that are part of a given environment.

Explain the types of foods used in space, Explain the types of foods used i...

Explain the types of foods used in Space? The various types of foods are enumerated herewith. Thennostabilized (T): Heat processed foods ("off-the-shelf' items) in aluminium

Explain assessment of iron status - serum ferritin, Explain assessment of i...

Explain assessment of iron status - Serum Ferritin? Serum Ferritin: This method is indicative of iron stores. As we know, a long term negative iron balance first results in dep

Define feeding and nutritional management of spinal trauma, Define the Feed...

Define the Feeding and Nutritional Management of spinal trauma? The main objectives of nutritional management are to meet the nutritional needs of the initial acute phase and

Primitive nervous system - nerve net, Primitive Nervous System - Nerve Net ...

Primitive Nervous System - Nerve Net A nervous system creates its appearance for the first time in the phylogeny among Cnidaria. In this group the nerve cells make an irregula

Immediate cardiac care (24- 72 hours) after operation, Immediate Care (24...

Immediate Care (24- 72 hours) All monitoring and medications continued. Flushing of arterial lines are done at regular intervals with heparin flush as well as whenever art

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