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

Illustrate the conductance of potassium channels, A decrease in parasympath...

A decrease in parasympathetic discharge to the heart leads to A. an increase in the conductance of F-channels in SA node cells. B. a decrease in the conductance of potassium

Animal husbandry-source of energy and protein, Source of Energy and Protein...

Source of Energy and Protein The by-products obtained from grain processing (brans), oil seed processing (oil meals) and pulses processing industries are the major and importan

Multidisciplinary approach to solving nutrition problems, Define Multidisci...

Define Multidisciplinary Approach to Solving Nutrition Problems? You must have realized by now that solving public nutrition problems represents a multidisciplinary challenge o

Briefly explain about gelation, Explain Gelation Gelation, which occurs...

Explain Gelation Gelation, which occurs when yolk is frozen and thawed, is apparently due to the aggregation of yolk lipoproteins because  of the imbalance and shift in water.

Explain about human sperm, Which one of the following statements about huma...

Which one of the following statements about human sperm is correct? 1. Acrosome has a conical pointed structure used for piercing and penetrating the egg, resulting in fertilis

Why water is a essential nutrient for life, Why Water is a essential nutrie...

Why Water is a essential nutrient for life? In this unit, we learnt that water in spite of being ignored, is an essential nutrient required for life. Though the content of tota

Principal sources of excessive nitrate and phosphate, What are the principa...

What are the principal sources of excessive nitrate and phosphate in rivers and lakes? Excessive nitrates and phosphates come majorly from sewage effluents and intensive agric

What might explain the pattern, A group of Ethiopians were assayed for CCR5...

A group of Ethiopians were assayed for CCR5-del32 deletion polymorphism. 223 were +/+, 64 were +/del32, and 6 were del32/del32. Are the observed data significantly different from H

Determine biologically compatibility of implant materials, Biologically com...

Biologically compatibility od implant materials An ideal implant material will elicit mainly physiological reactions within the surrounding tissues (bone, connective tissue and

Explain the types of fats, Jillian and Michael are in their freshman year a...

Jillian and Michael are in their freshman year at college. The two have been friends since grade school and the two of them enjoy getting together for dinner. Michael typically

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