Totipotency and Explant: Growing a Whole Plant from a Part

An explant is any part of a plant (a leaf piece, stem tip, root, etc.) that is taken out and grown in a test tube under sterile conditions on a special nutrient medium. NCERT says: 'any part of a plant taken out and grown in a test tube'. So the explant is the starting material, not the property.

Totipotency is the capacity to generate a whole plant from any single cell or explant. It is a PROPERTY (an ability) of the plant cell, not a structure. One cell holds all the genes needed to make the entire plant.

No. This is the most common mix-up. The explant is the physical plant part you place in the tube. Totipotency is the ability of that part or cell to grow back into a full plant. Explant = the thing; totipotency = the power the thing has.

It must be grown in vitro (in a test tube) under sterile conditions on a nutrient medium. NCERT lists the medium needs: a carbon source such as sucrose, plus inorganic salts, vitamins, amino acids and growth regulators like auxins and cytokinins.

Because tissue culture was developed when traditional breeding could not keep pace with food demand. Totipotency is the biological basis of tissue culture, which then leads to micropropagation and somaclones used to make food plants like tomato, banana and apple on a commercial scale.

Totipotency: the capacity to generate a whole plant from any cell or explant. Explant: any part of a plant taken out and grown in a test tube under sterile conditions on nutrient medium.

Scientists learnt during the 1950s that whole plants could be regenerated from explants. This is the fact NCERT states, so remember the decade for NEET.

Growth regulators like auxins and cytokinins are added, along with sucrose (carbon source), inorganic salts, vitamins and amino acids.

No. Totipotency is the ability of one cell/explant to form one whole plant. When this is used to make thousands of plants quickly, the process is called micropropagation, and those plants are somaclones.