The synthetic auxin 2,4-D is commonly used as a __________.

Correct option is C

The correct answer is (C) herbicide.

2,4-D (2,4-dichlorophenoxyacetic acid) is a synthetic auxin, widely used as a herbicide to control broad-leaved weeds. It mimics the natural plant hormone auxin, which regulates plant growth. By overstimulating plant growth, 2,4-D causes uncontrolled cell elongation in weeds, leading to their death. This selective herbicide does not affect grasses, making it useful for crops like corn, wheat, and rice.

Information Booster

• 2,4-D is one of the most widely used herbicides due to its effectiveness in controlling broad-leaved weeds.
• It works by disrupting the normal growth processes in plants, especially by overstimulating growth, leading to abnormal cell division and death.
• 2,4-D is selective, meaning it targets broadleaf weeds while leaving grasses like cereal crops unharmed.
• It has been extensively used in agriculture since its development in the 1940s and is still a popular choice for weed management.
• The chemical is often applied through spraying and can be absorbed through both leaves and roots of weeds.
• It has been used in the management of lawns, golf courses, and non-crop areas, as well as forestry.

Additional Information

(A) Signalling hormone – Auxins like 2,4-D play an important role as signaling hormones in plant growth, but the specific use of 2,4-D as a herbicide is focused on weed control rather than natural growth regulation.
(B) Defense hormone – While plants produce defense hormones like jasmonic acid to protect against pests and pathogens, 2,4-D is not involved in defense responses.
(D) Stress hormone – Stress hormones in plants like abscisic acid (ABA) regulate responses to environmental stress, such as drought. 2,4-D does not function as a stress hormone but influences growth processes.