Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Egg - Synergids
The three cells of the egg apparatus are arranged in triangular fashion with the egg sharing a common wall with the two synergids and the central cell. In the egg the wall is thicker at the micropylar end and is absent at the chalazal end. At this end the lateral walls of the egg cell appear to join the central cell wall. The egg cell wall is traversed by plasmodesmata on the sides of the two synergids and the central cell but not at its outer face. The egg cell becomes highly polarized early in its development. Polarity is expressed by the aggregation of cytoplasmic elements at the chalazal end of the cell. The micropylar end of the cell is occupied by a large vacuole. Thus, the distribution of the vacuole and cytoplasm in the egg cell is just the opposite of that in the synergids.
The ultra structure of the egg cytoplasm indicates that it is inactive. The mitochondria show only a few cristae. But for Zea mays, dictyosomes are either absent (Epidendrum) or are only a few in numbers. Where present, the dictyosomes exhibit an inactive state. Plastids are present in the egg; they often contain a striking difference from the male gametes. The egg cytoplasm is rich in ribosomes. In Plumbago capensis where the embryo sac lacks synergids. However many finger- like wall projections arise at the micropylar end of the egg cell. They resemble the filiform apparatus of the synergids. In this plant the egg cell seems to have taken over the role of synergids in addition to its own gametic function.
Development of Reserves - Conservation of Wildlife Establishment of Biological reserves, National parks, Forest reserves, Wildlife refuges and Biosphere reserves are effective
Do all mammals have a placenta? Mammals of the monotreme group (echidnas, platypus,) are oviparous, egg-laying, and they do not have a placenta. Mammals of the marsupial group
What is natural selection? Natural selection is the method by which organisms that have certain favorable traits are better capable to survive and make successfully than organi
Which of the following is a situation in which a closed-loop negative feedback system is converted to an open-loop system? A disease that destroys all the A. V2 Receptors in a
Concerning the sex chromosomes of the XY system which type of gamete do the male and the female individuals respectively produce? An Individual of the female sex is XX and thus
Systems of Human Body Many organs work in a coordinated'manner to form a system. For example in our-body the nose, the trachea and the lungs form the respiratory system. Table
Membrane is any delicate sheet that divides one region from other blocking or permitting (selectively or completely) the passage of substances. The skin, for example, can be consid
Osmotic and Ionic Regulation The ammonotelism, ureotelism and uricotelism are the adaptations of the animals for the removal of toxic nitrogenous wastes and thereby maintain
Q. What are the signs of myocardial disease? One manifestation of congestive cardiac failure is decreased exercise tolerance depending on the level of compensation. This leads
Intergenic: Amongs the two genes; for example intergenic DNA is the DNA found amongs two genes. The term is frequently used to mean non-functional DNA (or at least DNA with no kno
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd