Morphogenesis and totipotency, Biology

Assignment Help:

Morphogenesis and Totipotency

A chlamydomonas mother cell gives rise to two daughter cells by a simple division. But a leaf cell cannot give rise to a new plant except in cases like Bryophyllum or Kalanchoe. What makes a daughter cell of a zygote to loose the 'potential' to develop into a whole plant? Or if all the daughter cells possess this potential- i.e. if they are totipotent-why it does not express? These questions troubled Haberlandt-hundred years ago. He postulated that any living plant cell should be able to grow into a full plant. He experimented with mesophyll cells at a time when tissue culture had not been unheard for. His experiments failed because we now know that isolated mesophyll cells are not really easy to grow to unleash their morphogenetic potential.

F.C. Steward-who took up this work sixty years later-successfully cultured whole carrot plants from carrot phloem parenchyma cell. He published the papers in the American Journal of Botany in the late 1950's. Steward and his coworkers took 2 mg. tissues of secondary phloem of carrot roots and grew them in special flasks with nipples or tubes called tumble tubes. The medium was whites' medium with coconut water. These tubes/flasks were mounted on a wheel that was rotated on a shaft at the rate of 1 r.p.m. So that the pieces were alternately aerated and bathed in the liquid medium. There was an enormous increase in size of the explants. A callus ensued. A few peripheral cells slaughtered off into the medium and started dividing and gave rise to clumps,-occasionally with roots these could be transferred to semi-solid medium in (still) tubes. Shoots arose opposite the roots to yield full plants. Subsequently other parts were also used to, demonstrate cellular totipotency.


Related Discussions:- Morphogenesis and totipotency

What do you understand by herbarium ethics, Q. What do you understand by He...

Q. What do you understand by Herbarium ethics? You should also know that herbaria provide us with policy statements including such information as 1) filing arrangements, 2) res

Simple precautions to prevent injuries, When resheathing needles, simple pr...

When resheathing needles, simple precautions to prevent injuries are to: 1. use only one hand to scoop the cap 2. hold the sheath with a hemostat (suggested but will require

Recognize the eight stages of meiosis, Can you recognize the eight stages o...

Can you recognize the eight stages of meiosis based on the location and behavior of the chromosomes? Drag the diagrams of the stages of meiosis onto the targets so that the four st

Which responds to electrical signals, You have identified a protein in a ce...

You have identified a protein in a cell that you know that comes from the human body. With respect to that protein you have also determined that it allows sodium ions to go through

Explain spermatocyte I and spermatocyte II, What is the difference between...

What is the difference between spermatocyte I and spermatocyte II? The spermatocyte I (2n) undergoes the primary division of meiosis (meiosis I) originating two spermatocyte II

What are plant root hairs, What are plant root hairs? Where can they found ...

What are plant root hairs? Where can they found and what is their function? The Root hairs that are external elongated projections of the root epidermis and their role is to in

How can the immune memory lead to the efficacy of vaccines, How can the imm...

How can the immune memory lead to the efficacy of vaccines and also produce allergies? Vaccines are controlled inoculations of fragments of infectious agents or of inactive inf

Show the ph range of natural honey, Q. Show the pH range of natural honey? ...

Q. Show the pH range of natural honey? The pH of natural honey ranges from 3.4 to 6.1. Acidity of honey is primarily due to presence of acids such as gluconic acid, pyruvic a

Depth and currents, Depth and Currents Depth The sea is v...

Depth and Currents Depth The sea is very deep varying in different regions. Generally life extends to all depths but is confined more to the continental shelf and

Explain about human digestive system, Which organs of the body are part of ...

Which organs of the body are part of the human digestive system? The digestive system, also called as "systema digestorium", or gastrointestinal system, is composed of the dige

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