Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
Determine Balanced Diet For Celiac Disease? Energy: initially the children are seen to be malnourished, thus 100-120 Kcal/kg body weight/day with gradual increase to 150 Kcal
Which of the following serves as an effector, or as part of an effector, that functions in a negative feedback system? A. Glycogen Receptors in the plasma membranes of liver ce
Q. What is the main risk factor for lung cancer? The major risk factor for lung cancer is tobacco smoking. In The large number of cases of this kind of cancer is due to the inc
What is Nagel's Anomaloscope The patient is asked to match a yellow with a mixture of red and green wave lengths. A defect can be detected based on the amount of red and green
Define role of Vitamin D in controlling gene expression? Vitamin D is a secosteroid that is metabolically activated and degraded through the actions of three cytochrome P450 hy
what are the ecological importance of molluscus
Which of the following best describes the role that restriction enzymes play in bacteria? A. Restriction enzymes recognize and digest bacteriophage genomes after an initial inf
Define Age as a determinants of nutrient requirements? Age: Requirements change with increasing age between birth and maturity. Nutrient requirements per unit body weight are h
Define the Roller Drying (Drum drying) Method? One of the important techniques for drying liquid food products is the roller drier. Like spray drying, roller drying can only be
Why do ribosomes move along mRNA during translation? During translation the ribosome always exposes two mRNA codons to be translated by moving along the mRNA. When a peptide bo
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd