Elementary plant Biochemistry and Biotechnology (2+1)

Fundamentals of Micropropagation

 
• Multiplication of genetically identical copies of a cultivar by asexual reproduction is called clonal propagation. In nature, clonal propagation occurs by apomixis (seed development without meiosis and fertilization) and/or vegetative propagation (regeneration of new plants from vegetative parts). Tissue culture has become popular method for vegetative propagation of plants.
  


• Aseptic method of clonal propagation is called as Micropropagation and it offer the advantage of large number of true-to-type plantlets can be produced with relatively short time and space from a single individual. Since any small part of the plant can be used to produce complete plantlets, this method is called as micropropagation. It is the fact that micropropagation is the one of the commercially viable methods of clonal propagation of the horticultural crops. E.g. Orchids.

Cellular Totipotency

• The inherent potentiality of a plant cell to give rise to a whole plant is described as cellular totipotency. This is a capacity which is retained even after a cell has undergone final differentiation in the plant body. In plants, even highly mature and differentiated cells retain the ability to regenerate to a meristematic state as long as they have an intact membrane system and a viable nucleus. This is contradicting to animals, where differentiation is generally irreversible.


• For a differentiated cell, to express its totipotency, it first undergoes dedifferentiation followed by redifferentiation. The phenomenon of a mature cell reverting to the meristematic state and forming undifferentiated callus tissue is termed ‘dedifferentiation’. The phenomenon of conversion of component cells of callus tissue to whole plant or plant organs is called as ‘redifferentiation’.