JEE Main & Advanced Chemistry Chemistry in Everyday Life / दैनिक जीवन में रसायन Plant Growth Hormones

These are the organic substances which are synthesized in minute quantities in one part of the plant body and are transported to another part where they influence specific physiological processes to regulate growth, differentiation and development.

Plant growth hormones are grouped into two main types : (i) growth promoters (e.g., auxins, gibberellines, cytokinins etc.) and (ii) growth inhibitors (e.g. ethylene, abscisic acid, maleic hydrazide etc.) Many of these hormones, especially the synthetic ones are now-a-days widely used in agricultural practices e.g., as weedicides (2, 4-Dichlorophenoxyacetic acid or 2, 4-D), as rooting hormones (Naphthalene acetic acid or N.A.A. etc.), to induce flowering in certain plants (e.g., N.A.A., I.B.A.), to prevent pre-mature fruit drop (e.g., 2, 4-D, I.A.A., I.B.A., etc.), for storage of potato tubers–where they prevent sprouting (e.g., N.A.A.), to increase sweetness of fruits (e.g., I.B.A.), to increase yield of certain crops (e.g. gibberellins increase yield of pea, bean tomatoes, pepper, cucumber, lettuce, cabbage, etc.), in tissue culture (e.g. cytokinins), artificial ripening fruits like banana, mango (e.g. ethylene).