Morphophysiological changes in tissue culture of Petunia hybrida in response to the allelochemical coumarin

Coumarin induces metabolic and morphofunctional changes in Petunia hybrida leaf explants. The tissues grown in the presence of coumarin show long roots with few root hairs. However, the leaf explants grown with indoleacetic acid show short roots with abundant root hairs. The presence of both indoleacetic acid and coumarin induces long roots with numerous root hairs. The presence of both indoleacetic acid and coumarin induces long roots with numerous root hairs. Peroxidase and IAA-oxidase activity were analysed. Results obtained indicate that coumarin may control the endogenous auxin level interfering with peroxidase systems. The IAA-oxidase activity remains low in the culture tissues treated with coumarin. Peroxidase and esterase isoforms in leaf explant extracts, treated with coumarin, exhibit a pattern similar to those induced by indoleacetic acid. Acting as a plant growth regulator and affecting auxin metabolism, coumarin interferes with differentiation processes.