Question

Bioassay of gibberellins is carried out by
A. Pea test
B. Dwarf corn test
C. Lettuce hypocotyl test
D. All of the above

Answer 1

Hint: Plant hormones are a type of chemical compound which present in plants in very low concentration. This chemical substance is responsible for the growth and development of the plant. Gibberellins are a plant hormone which is the derivative of the terpenes.

Complete answer:
Plant hormone can be defined as a chemical substance that regulates the growth and development of the plant. It acts as an internal factor of the different cellular and metabolic processes of plants.
Gibberellin is the type of plant hormone. This hormone is produced by the plastids to regulate the growth of plants. This hormone is acidic in nature and commonly found in higher plants and fungi. Gibberellin hormone helps in bolting which is the sudden elongation of internodes just before flowering in rosette plants like cabbage. It also delays senescence, induces parthenocarpy, and breaks seed dormancy.
The identification of gibberellin hormone is based on a common principle which is a high response of the stem or its individual portions to this phytohormone i.e. plant hormone. Michalski performed several extensive comparative works for investigating various gibberellin bioassay systems. He studied that the most sensory system was lettuce. It responded to ${10^{ - 10}}{\text{g per ml}}$ of gibberellic acid.
The response of the phytohormone is one of the important properties of the bioassay. Michalski discovered that the specialized property of gibberellins, namely its ability to affect an entire plant, disappears if only part of a plant is used for a bioassay. This feature is also seen on intact plants of rice, maize, pea, cucumber, and lettuce.
The bioassay has a number of advantages such as the production of α-amylase is one step closer to the primary site of action of GA. The release of α-amylase is not affected by solvent residues and it is completely specific for gibberellin. Also, the release of α-amylase is not affected by substances other than gibberellins present in crude plant extracts.
Thus, the right option is D.

Note: Plant hormone or phytohormone regulate the various processes of plants. Gibberellins are a type of plant hormone which is the derivative of the terpenes. The response of the phytohormone is one of the important properties of the bioassay. Michalski discovered the property of gibberellins. Bioassay of gibberellins is carried out by pea test, dwarf corn test and lettuce hypocotyl test