2.1.  Micropropagation vs. conventional method of propagation

All living plant cells, irrespective of their nature of specialization and ploidy level, have been shown to regenerate plants via organogenesis or embryogenesis. The latter involves a highly specialized mode of development that normally occurs only inside the seed, under the cover of several layers of parental tissues. Consequently, the observation of developing embryos and their isolation in intact and living conditions for experimental studies have been extremely difficult. In vitro production of embryos from somatic and gametic cells has opened up the possibility of obtaining large numbers of embryos of different stages, enabling investigations on cellular, genetic and physiological control of embryogenesis (induction, pattern formation, organ differentiation and maturation). In vitro expression of cellular totipotency and other techniques of plant tissue culture have also facilitated and/ or accelerated the traditional methods of plant improvement, propagation and conservation.

 

2.2.  Micropropagation vs. vegetative propagation

The vegetative propagation has been conventionally used to raise genetically uniform large scale plants for thousands of years. However, this technique is applicable to only limited number of species. In contrast to this, micropropagation has several advantages which are summarized here:

i.  The rapid multiplication of species difficult to multiply by conventional vegetative means. The technique permits the production of elite clones of selected plants.

ii.   The technique is independent of seasonal and geographical constraints.

iii.   It enable large numbers of plants to be brought to the market place in lesser time which results in faster return on the investment that went into the breeding work.

iv.   To generate disease-free (particularly virus-free) parental plant stock.

v.   To raise pure breeding lines by in vitro haploid and triploid plant development in lesser time.

vi.  It can be utilized to raise new varieties and preservation of germplasm

vii.  It offers constant production of secondary medicinal metabolites.

 

2.3.  Cell differentiation

During in-vitro and in vivo cytodifferentiation (cell differentiation), the main emphasis has been on vascular differentiation, especially tracheary elements (TEs). These can be easily observed by staining and can be scored in macerated preparations of the tissues. Tissue differentiation goes on in a fixed manner and is the characteristic of the species and the organs