Tetrasporic embryo sacs, Biology

Assignment Help:

Tetrasporic Embryo Sacs

In this group neither of the meiotic divisions is accompanied by wall formation so that at the end of meiosis all the four haploid nuclei remain in a common cytoplasm forming what is termed a coenomegaspore. A tetrasporic embryo sac is more heterogeneous than a bisporic embryo sac because the four products of meiosis involved in its formation are genetically different. The nuclear behavior in tetrasporic embryo sacs is quite variable. The arrangement of the four nuclei in the coenomegaspore before the beginning of post-meiotic mitosis is of three types:

(A) 2+2 arrangement; two nuclei at the micropylar ad and two of the chalazal end

 (B) 1+1+1+1 arrangement; one nucleus at the micropylar end, one at the chalazal end, and two placed laterally, one in each side, and

(C) 1+3 arrangement; one nucleus at the micropylar end and three at the chalazal end. Depending on whether nuclear fusion occurs or not, the number of the post-meiotic mitosis in the coenomegaspore and final organisation of the embryo sac, tetrasporic embryo sacs are of many types.


Related Discussions:- Tetrasporic embryo sacs

What is the basic role of botanic garden, Q. What is the basic Role of Bota...

Q. What is the basic Role of Botanic Garden? A botanic garden makes us to simply enjoy the beauty and variety of nature. The pleasure of admiring turns us into good naturalists

Transport into the cytosol, Fatty  acids  are  synthesized  in  the  cytoso...

Fatty  acids  are  synthesized  in  the  cytosol,  but  acetyl  CoA  is  produce  from pyruvate in the mitochondria. Therefore the acetyl CoA must be transferred  from  the mitocho

Describe the biological parameters of living organisms, Describe the Biolog...

Describe the Biological parameters of living organisms Biological parameters which include living organisms constitute an important component of soil.  Even though organisms fo

Describe the term intellectual property rights, Question 1: Describe th...

Question 1: Describe the term Intellectual Property Rights. Show the difference between Patents, industrial designs, and trademarks. Define the term Intellectual Property

How do organisms adjust to changes in temperature, How do organisms adjust ...

How do organisms adjust to changes in temperature? Some of the most ordinary way for an organism to adjust to changes in body temperature is by perspiration or panting.

Explain about the niacin (nicotinic acid) deficiency, Explain about the Nia...

Explain about the Niacin (nicotinic acid) deficiency? Niacin (nicotinic acid) deficiency classically results in pellagva, which is a chronic wasting disease associated with a c

The chance of fertilisation in humans, Explain why the chance of fertilisat...

Explain why the chance of fertilisation in humans is restricted to only a few days each month. Sperms can fertilise an ovum for up to about three days after entering the female

Tectology ia the study of structural organization of body, Tectology:  Thi...

Tectology:  This is the study of structural organization of body. Tectology is a term which is used by Alexander Bogdanov to describe a discipline which consisted of unifying all

Explain hepatitis c, Hepatitis C It provides sustained viral responses ...

Hepatitis C It provides sustained viral responses (SVRs) of 54% to 63%. When used as monotherapy, peginterferons once weekly are more effective than standard interferon 3 times

Determine the bony walls of the maxillary sinus, Determine the bony walls o...

Determine the bony walls of the Maxillary sinus: The Anterior wall of the sinus has thin compact bone above the apex of the canine teeth which may extend to the lateral pirifor

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