Morphogenesis and totipotency, Biology

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.

Posted Date: 1/24/2013 1:24:00 AM | Location : United States







Related Discussions:- Morphogenesis and totipotency, Assignment Help, Ask Question on Morphogenesis and totipotency, Get Answer, Expert's Help, Morphogenesis and totipotency Discussions

Write discussion on Morphogenesis and totipotency
Your posts are moderated
Related Questions
Explain Suturing - Endodontic Surgery a. Purpose of suturing: approximation of inside tissues and stabilize the flapped mucoperiosteum b. Major problem of suturing in oral t

EVIDENCES OF EVOLUTION - The evidences of organic evolution derived from many lines of study indicate that present day forms have arisen by gradual changes from pre existing fo

Q. Explain about Pre - Diabetes? Pre - Diabetes is a condition where blood sugar level is above normal but below to be diagnosed as diabetes mellitus. It has been found that

REPRODUCTIV E ISOLATION - According to the biological species concept, members of one species are reproductively isolated from members of all other species. Accordingly, re

Define Disadvantages of Direct Microscopic Count? 1. Small cells are difficult to see under the microscope and may be missed. 2. It gives total count, i.e., both live and de

What are the major morphological differences between monocot plants and dicot plants? The main differentiation criteria among monocots and dicots are: number of cotyledons (see

What is the exchange list? IL is a grouping of foods in which specified amounts of all the foods provide approximately equal amount of (the same amount) carbohydrate, protein a

Q. What are the problems that vertebrates needed to solve to adapt to the terrestrial environment since they came from the aquatic habitat? How evolution does solve those problems?

What is nucleus where it is found? Nucleus :  The nucleus is present only in eukaryotic cells. It is the control center and is generally found in the center of the cell. The

Q. What are other important human diseases caused by protozoans? Some other significant protozoan infections are amebiasis, trichomoniasis, giardiasis, leishmaniasis, meningoen