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

Shortness of breath, Shortness of Breath It is a subjective sensation...

Shortness of Breath It is a subjective sensation of being unable too draw in enough air to breathe. Most often, this is associated with congestive cardiac failure and may

Determine about the accommodation of eye, Determine about the Accommodation...

Determine about the Accommodation of eye Accommodation is the ability of the overall refracting power of the eye to change to clearly view objects at different distances. This

Effects of cardiac output and hormones, Excluding the effects of cardiac ou...

Excluding the effects of cardiac output and hormones, describe the other factors that may affect blood pressure and blood flow in a middle-aged man who is exercising in an aerobics

Which aqueous solution has the lowest ph, The aqueous solution with the low...

The aqueous solution with the lowest pH is: Select one: a. 0.01 M HCl. b. 0.1 M acetic acid (pKa = 4.86). c. 0.1 M formic acid (pKa = 3.75). d. 0.1 M HCl. e. 10 t

What is end-to-end anastomosis subclavian flap aortoplasty, What is End-to-...

What is End-to-End Anastomosis with Subclavian Flap Aortoplasty ? The two operations can be combined as a single procedure. Medially end-to-end anastomosis is done between the

Centrosome, structure of centrosome and work

structure of centrosome and work

What do you understand by metanephridia, What do you understand by Metaneph...

What do you understand by Metanephridia? An excretory-osmoregulatory organ comprising a ciliated funnel, nephrostome, connected to tubules that lead to the external nephridiopo

Electrodialysis, This method is used for the desalination of water i.e., fo...

This method is used for the desalination of water i.e., for the removal of dissolved mineral salts, acids, alkalis and also the radioactive substances from the effluents. Electro d

What is meant by substrates of enzymatic reactions, What is meant by substr...

What is meant by substrates of enzymatic reactions? Substrates are reagent molecules upon which enzymes act. The enzyme has spatial binding sites for the attachment of its s

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