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 are the symptoms of diverticulosis, Q. What are the symptoms of divert...

Q. What are the symptoms of diverticulosis? Depending on the site of diverticula the symptoms may appear. It occurs most often in sigmoid colon and frequency increases with age

Deifition, what''s the define of mitochodria

what''s the define of mitochodria

Define the foam mat drying method, Define the Foam Mat Drying Method? T...

Define the Foam Mat Drying Method? This process is a development of the vacuum puffing but, instead of employing a vacuum to foam the material, it is initially foamed by suitab

Counselling elderly diabetics, Q. Counselling Elderly Diabetics? The ri...

Q. Counselling Elderly Diabetics? The rising trend of diabetes in the elderly population is a challenge for health care providers. The problems which make the diabetes treatmen

Describe ps with atrial right to left shunt in details, Describe PS With At...

Describe PS With Atrial Right To Left shunt in details? This group of patients has cyanosis due to light to left shunt at atrial level. The diminution in PA pressure and PBF ma

Most appropiate hypothesis about the origin of life on earth, What is the m...

What is the most accepted hypothesis about the origin of life on earth? How does it compare to the other main hypotheses? The heterotrophic hypothesis is the strongest and most

Treatment of water for industrial use, Water is widely used in various proc...

Water is widely used in various process applications in industry. Other major industrial uses are boiler feed water and cooling water. The king and degree of treatment of water in

Sequence was found in a 21 base dna polymer., Suppose the following base se...

Suppose the following base sequence was found in a 21 base DNA polymer. 3' TAC   TTA   GGC   TCC    GTT    CAG   ATT       5' 1. Provide the nucleotide sequence complementary

Explain the sedimentation - air sampling, Explain the Sedimentation - Air S...

Explain the Sedimentation - Air Sampling? It is the simplest method, which involves exposing agar plates in air for specified time at a location to be sampled.  Microorganisms

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