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

Pair of alleles has different allelesdominance between them, Whenever a pai...

Whenever a pair of alleles has different alleles is there dominance between them? Not in all cases of a gene includes two different alleles is the dominance complete. There are

Metaphase chromosomes, Metaphase chromosomes: Each metaphase chromoso...

Metaphase chromosomes: Each metaphase chromosomes is a duplicated structure which consists of two sister chromatids, attached at a point called centromere or primary constric

Tolerance range, Maximum and minimum range of an animal with the factors of...

Maximum and minimum range of an animal with the factors of Ph Salinity Pressure Relative human

What are the major novelties presented by fishes, Q. What are the major fea...

Q. What are the major features of fishes associated to the habitat where they live? Fishes are all aquatic animals and thus they have a hydrodynamic elongated body appropriate

Virus, assignment order

assignment order

What are the hormones secreted by the adrenal cortex, Q. What are the hormo...

Q. What are the hormones secreted by the adrenal cortex? What are their respective functions? The cortical portion of the adrenals secretes hormones of the corticoid (or cortic

Main phases and clinical manifestations of schistosomiasis, Q. What are the...

Q. What are the main phases and clinical manifestations of schistosomiasis? The Schistosomiasis has acute and chronic phases and Days after the infection the cercarial dermatit

Describe in detail about the unicellular eukaryotes, Describe in detail abo...

Describe in detail about the unicellular eukaryotes Animal cel1.s and many types of unicellular eukaryotes contain centrioles, which are cylindrical in structure, about 0.15 m

Causes of diabetic ketoacidosis, Q. Causes of Diabetic Ketoacidosis? Th...

Q. Causes of Diabetic Ketoacidosis? The causes of Diabetic Ketoacidosis (DKA) are the following: - Missing of insulin injection - Infection - Trauma (injury) - Myoc

What is food pyramid, Food Pyramid The diabetes food pyramid divides fo...

Food Pyramid The diabetes food pyramid divides food into six groups. These groups vary with each other on the basis of size occupied in the pyramid. The largest i.e. grains, br

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