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

Define the energy cost of growth, Define the Energy Cost of Growth? The...

Define the Energy Cost of Growth? The energy cost of growth has two components: 1) The energy needed to synthesize growing tissues; and 2) The energy deposited in these tis

Define the criteria for assessment of thiamin status, Define the Criteria f...

Define the Criteria for Assessment of Thiamin Status? Thiamin status has been assessed by measuring urinary thiamin excretion under basal conditions or after thiamin loading, t

Name which part of the seed in other monocotyledons, The scutellum observed...

The scutellum observed in a grain of wheat or maize is comparable to which part of the seed in other monocotyledons? 1. Cotyledon 2. Endosperm 3. Aleurone layer 4. Plum

Why is a leguminous crop rotation used in agriculture, Q. Why is a legumino...

Q. Why is a leguminous crop rotation used in agriculture? The Leguminous crop rotation and other crop rotations are used in agriculture for the reason that in these plants many

Explain the absence of passive fit of the prosthesis, Absence of Passive Fi...

Absence of Passive Fit of the Prosthesis A passive fit of the prosthesis reduces long term stresses in the superstructure, implant components and the bone adjacent to the impla

Functions of ovary, Functions of Ovary The ovary of vertebrates perfor...

Functions of Ovary The ovary of vertebrates performs the following functions:   Production of eggs, Synthesis of hormones needed for the chemical coordination of repr

Heart in fishes, Fishe s - Heart is 2 chambered 1 auricle & 1 ventr...

Fishe s - Heart is 2 chambered 1 auricle & 1 ventricle present. Sinus venosus, truncus or conus arteriusus present. Only impure blood come in heart so heart is venous he

Respiration, what is the organ of respiration in snaks

what is the organ of respiration in snaks

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