Please explain how a cutting from a plant can form an entire new plant.

Question

Answer should include a discussion of cell potency. I propagated a cutting from a plant and it formed an exact replica of that plant. How does this happen? Why can't you propagate a cutting from a human and expect it to form an exact clone?

Answer 1

 Hi, Ryan,

 

Firstly, cutting from a plant always does not lead to a new plant. However, if a cutting is made at a time when the plant is in proliferating and regenerating stage then it would develop into a new plant when transplanted in proper condition of growth.  

 

Salamanders are animals, they are vertebrates and belong to class amphibia. If you cut a limb of salamander, it would regenerate the entire limb. However, higher vertebrates including reptiles, birds and mammals have lost that ability of regeneration. This regenerative ability is a fascinating field of research where many labs around the world are working to decipher this mystery.

 

Here is a brief cellular mechanism that is known in both plants and animals during the course of regeneration:

 

Upon cut, an injury is made. This injury induces activation of  certain  genes, synthesis of certain proteins in the cells at the site of injury, they first form a blastema (a stump in plants where no regeneration would occur) where massive cell proliferation begins through gene activation and cell-division.  A ball of undifferentiated cells is formed rapidly. Then the factors that induce tissue-specific differentiation, would tell cells to differentiate in specific tissues: roots, stems and leaves in plants and muscle,  bone, skin etc.  in animals. Plants are able to generate an entire plant, salamanders are able to generate entire limb, some amphibians regenerate tail as well.

 

During the course of evolution, higher vertebrates have lost that ability, however, the current research is on the way where scientists take skin  cells from a patient with say atherosclerosis (heart condition). By genetic manipulation  researchers  make these cells forget that they are skin cells, the cells now think that they are undifferentiated cells. Researchers now add specific factors to these cells to make them differentiate into  say cardiomyocytes so that they can transplant these newly formed healthy cardiomyocytes to the heart with atherosclerosis in the patient.  At the site of transplantation in the diseases heart,  young cardiomyocytes  would make fresh and healthy heart cells and hopefully would cure atherosclerosis! The process is called regenerative medicine and very hot as well as well-funded topic of research.  

 

Hope it helps.