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

Biological adaptation, Biological Adaptation These adaptations depend ...

Biological Adaptation These adaptations depend on the geology and basic fertility of the region and some of the mechanisms that are especially well developed in tropical rain

Cleavage, CLE A V AG E - Holoblastic & unequal. First plane is meri...

CLE A V AG E - Holoblastic & unequal. First plane is meridional. 2 blastomeres are formed. 1 megamere & another micromere. 2nd plane is also meridional but at 90° to fir

Define the clinical experience of anorexia nervosa, Define the Clinical exp...

Define the Clinical experience of anorexia nervosa? Clinical experience suggests that many of the untoward consequences of refeeding can be minimized or avoided by starting the

Bovine leukemia, B ov i n e leukemia Bovine leukemia, also known as...

B ov i n e leukemia Bovine leukemia, also known as bovine lymphosarcoma or leucosis, is a lymphoproliferative neoplastic disease of bovines. The virus belongs to genus Delt

How nutritional status affects the bmr, How Nutritional status affects the ...

How Nutritional status affects the BMR? Under nutrition and starvation are the factors which require consideration. Prolonged under nutrition or starvation causes a reduction o

Define the functions of vitamin a, Define the Functions of Vitamin A? V...

Define the Functions of Vitamin A? Vitamin A (retinol) is an essential nutrient needed in small amounts by humans for the normal functioning of the visual system, growth and de

Direction of flow, Direction of flow--either towards or away from the trans...

Direction of flow--either towards or away from the transducer (positive or negative Doppler shifts). Timing-instantaneous velocity and direction of flow throughout the various

Of what importance are lactic acid fermentation to the cell, Of what import...

Of what importance are lactic acid fermentation and alcoholic fermentation to the cells that use these pathways? These pathways regenerate NAD, which the cells can use to keep

Explain cumulative interceptive supportive therapy, Cumulative Interceptive...

Cumulative Interceptive Supportive Therapy (ITI Consensus report) Systematic and continuous monitoring of the periimplant tissue conditions is recommended for the diagnosis of

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