Question

Which of the following shows correct chronological order of the events occurring during callus culture?
A. \[Callus\to cell\,division\to \exp lant\to addidtion\,\,of\,cytokinin\to acquire\,meristematic\,property\]
B. \[Explant\to callus\to cell\,division\to addition\,\,of\,cytokinin\to cells\,acquire\,meristematic\,property\]
C. \[Explant\to cell\,division\to callus\to addition\,\,of\,cytokinin\to cells\,acquire\,meristematic\,property\]
D. \[Callus\to Explant\to cell\,division\to addition\,\,of\,cytokinin\to cells\,acquire\,meristematic\,property\]

Answer 1

Hint: Plant tissue culture is a technique of growing cells, tissues, or organs in sterilized nutrient media under controlled aseptic conditions. The plant material to be cultured may be cells, tissues, or plant organs such as excised root tip, shoot bud, leaf petiole, inflorescence anther, embryo, ovule, or ovary. The plant part which is used to culture is called explants.

Step by step answer:
Before transferring on the culture medium, the explants are first of all disinfected by surface sterilization. Sterilization means the complete destruction or killing of microorganisms so that complete aseptic conditions are created for in vitro fertilization. When grown in specific culture mediums many plant tissue cells, portions of organs, or tissues start dividing and grow to form an unorganized mass of cells called a callus. The undifferentiated cells of callus are parenchymatous in nature. They differentiate into different types of cells after getting the different proportions of nutrients (i.e. sucrose) and growth hormones ( i.e. auxins and cytokinins ). Under the influence of different concentration of growth hormones and sucrose, the cells of the callus start differentiating to form root or shoot ( meristematic property or organogenesis)

Hence, the correct answer is option i.e.,
\[C.\,Explant\to cell\,division\to callus\to addition\,\,of\,cytokinin\to cells\,acquire\,meristematic\,property\]

Additional information:
Callus culture is easy to maintain by repeated sub-culturing and needed for several biotechnological works including plant regeneration, preparation of single-cell suspensions, isolation of protoplasts, and genetic transformation studies. They are commonly used for achieving cell biomass production.

Note: In Callus culture a plant tissue or explants is taken which is surrounded into the medium which first starts rapid cell division forming a callus.