Habituation in callus culture refers to:
Normal plant cell proliferation requires exogenous auxin to activate S-phase genes and cytokinin to induce mitotic cyclins. Habituation denotes acquired ability to divide without these supplements due to stable metabolic reprogramming. Prolonged culture selects variants overproducing cytokinins via isopentenyl transferase genes or auxins via YUCCA flavin monooxygenases, or mutations conferring constitutive signaling through type-B response regulators and auxin receptors TIR1. Epigenetic changes in promoter methylation lock these biosynthetic genes in active state, making trait heritable throug
Ref: Gautheret 1955 habituation; Meins & Binns PNAS 1979 hormone autotrophy; Taiz Plant Physiology Ch 21 cytokinin autonomy; NCBI NBK218342 habituation concept review.