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

Can you explain likar system with electrodes, Q. Can you explain Likar Syst...

Q. Can you explain Likar System with Electrodes? The 12 lead Mason - Likar system with electrodes is used. The plastic adhesive electrodes has self contained electrode jelly in

Regarding the complement system, Which of the following is not true regardi...

Which of the following is not true regarding the complement system?Answer This system involves a group of at least 20 proteins found in the blood plasma. During an infection, one p

Classify biomaterials and list some examples, Classify biomaterials and lis...

Classify biomaterials and list some examples. Biologic classification is based on tissue response and systemic toxicity effects of the implant and is divided into three classes

Succession, Similarities between autotrophic succession and heterotrophic s...

Similarities between autotrophic succession and heterotrophic succession

Enzymes in clinical diagnosis, ENZYMES IN CLINICAL DIAGNOSIS The ration...

ENZYMES IN CLINICAL DIAGNOSIS The rationale for measuring plasma or serum enzyme levels is based on the premise that these  levels reflect changes  that  have  occurred  in  a

Mycroboilogy mycoplasma, How we write assimgment about mycobiology of mycop...

How we write assimgment about mycobiology of mycoplasma in detail

Dietary management of oesophagitis, Q. Dietary Management fo oesophagitis? ...

Q. Dietary Management fo oesophagitis? Providing adequate nutrition support may require emphasis of different aspects during acute and chronic oesophagitis. In acute phase,

Neural process occurring in the recovery from brain injury, Neural process ...

Neural process occurring in the recovery from brain injury The neural process occurring in the recovery from brain injury are thought to be similar to the processes involved in

Biodiversity maintains, Biodiversity maintains the air we breathe and the w...

Biodiversity maintains the air we breathe and the water we drink. Green plants purify our air and our water by taking in carbon dioxide, regulating water vapour, releasing oxygen,

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