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.
what is the shape of blood platelets
general charcteristics
IMPORTANCE OF MENDELISM 1 . Improvement of Plants Hybridization is used for obtaining improved varieties of plants. This process results in combinations of desirable
Determine the Lateral Cephalometric Skull View The use of this modality is limited in preoperative evaluation in implant placement for advance cases where there is a need for b
Chromatin is made of DNA molecules associated to proteins known as histones.
Pisciculture: This is the culturing of fishes. There is a principal form of aquaculture called Fish farming, while other methods can come under mariculture. Fish farming main aim i
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
Access Cavity Perforation - Types of Root Perforation Can occur during access cavity perforation (specially in anterior) Due to misdirection of bur during access cavit
Polynephritis in cattle Contagious bovine polynephritis is a specific infection of urinary tract of cattle. The causative agent is Corynebacterium renale, a rod shaped gram-po
Q. Elimination of the risk factors - diabetes mellitus? In other words, in diabetes it refers to maintaining of normal body weight, healthy nutritional practice, regular physic
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