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!
Female Gametophyte
The development of a female gametophyte is initiated with the enlargement of one of the megaspores (usually the one close to the chalaza in a linear tetrad) followed by three mitotic divisions. Thus, the female gametophyte, also called the embryo sac is almost always a 7-celled or 8-nucleate structure. The eight nuclei thus formed organize into the egg apparatus, central cell with two polar nuclei and three antipodal cells. This mode of embryo sac development occurs in the majority of flowering plants.
There are variations from this mode of female gametophyte development. In order to visualize these deviations let us recall the formation of megaspore tetrad. Out of the four megaspores, three degenerate and only one participates in the formation of embryo sac. This mode of development of female gametophyte is known as the monosporic type. In some plants, two megaspores out of four participate. For example, if after meiosis, the lower or the upper dyad produces the embryo sac and the other degenerates, the development is termed bisporic. Sometimes, cell plate formation does not occur after any of the meiotic divisions and all the four megaspore nuclei contribute to embryo sac formation. 'This is called tetrasporic type of development. Depending upon the orientation and subsequent behavior of the megaspore nuclei and their derivatives, the tetrasporic gametophyte may be of several types.
Normal 0 false false false EN-IN X-NONE X-NONE
Define the Disturbances in Fluid Balance? The correct functioning of cells and tissues depends on appropriate concentrations of nutrients; so any abnormal loss or accumulation
If baroreceptors are primed to detect blood pressure changes and compensate for them, how is it that some patients suffer from chronic hypertension?
B a b e s i o s i s It is also known as red water disease or cattle tick fever and is characterized by fever, intravascular haemolysis, acute anaemia and haemoglobinur
Similarities in cloning and selective breeding cloning (not transgenesis) and selective breeding both transfer whole genome both selective breeding and cloning have t
Name two possible why the number of live bacteria cell have reached the stationary growth by 60hrs and start to die off after 12hrs?
Petroleum Liquid fuels are widely used for industrial and domestic purposes. Almost all internal combustion engines run on liquid fuels. Liquid fuels are also used in heat gene
write the names of these animals? 1.amoeba 2.sponge 3.hydra 4.liverfluck 5.Iscariot 6.leech 7.insects 8.oyster 9.starfish 10.frog
Q. Why is the sun the "motor" of the water cycle? The sun can be considered the motor of the water cycle for the reason that upon its energy the transformation of liquid water
What is Anti-arrhythmic pacemaker defibrillators ? Antiarrhythmic drugs (AADs) are classified according to whether they exert blocking actions predominantly on sodium, potassiu
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