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.
Long-Day Plants (LDP) - Plant Responses to Light-Dark Cycles The definition of this is exactly opposite to short-day plant. That is those plants which flower when given more t
Q. What are the Yeasts? Like mold, the term "yeast" is commonly used but hard to define. As used here it refers to those fungi which are generally not filamentous but unicellul
what is the xternal & internal respiration in frog
What Devices Used for Oxygen Therapy? Variable performance systems: With these devices, the FiO 2 would vary depending on the patient's breathing pattern. In general, rapid, s
Define Characteristics of probiotics? Are microorganism Promote a healthy intestinal microflora Ensure colonization resistance to pathogens Destruction of ge
illustrate vernalisation?
Directive and Non-directive Counseling Directive Counseling tends to be appropriate when the counselor is aware of the problem and/or is concerned about the behavio
Carbohydrate Digestion Simple sugars like glucose and fructose can be absorbed and metabolised directly but disaccharides such as sucrose or lactose and polysaccharides such a
Counselling a diabetic patient and their family members is very important as patient has to modify the life style and diet and needs family support. Therefore it is important for y
3 benefits humans get from coral
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