EVERYDAY SCIENCE

Detailed explanation-1: -Since 1937, gibberellin (GA), ethylene, cytokinin, and ab-scisic acid (ABA) have joined auxin as phytohormones, and together, they are regarded as the “classical five” (Fig-ure 1).

Detailed explanation-2: -The classical plant hormones, such as auxin, abscisic acid (ABA), brassinosteroids (BRs), cytokinin (CK), salicylic acid (SA), jasmonate (JA), and ethylene (ET), integrate environmental stimuli and endogenous signals to regulate plant defensive response to various abiotic stresses, including heat.

Detailed explanation-3: -The five major phytohormones are – auxins, gibberellins, cytokinins, ethylene and abscisic acid. There are also other phytohormones that affect the plant’s physiological processes like brassinosteroids, salicylates, jasmonates, strigolactones, etc.

Detailed explanation-4: -Auxin: It promotes cell enlargement and cell differentiation in plants. Gibberellins: It breaks the dormancy in seeds and buds. Cytokinins: It promotes cell division in plants. Abscisic acid: It promotes the closing of stomata.