Induction of auxin-nonrequiring tobacco calluses and its reversal by treatments with auxins1

摘要

Auxin-nonrequiring calluses were induced with high frequencies by short treatments with auxins from auxin-requring ones. Auxin-requiring calluses T22 and XD6S2, subcultured on a medium containing 1 mg/liter IAA as plant growth regulator, required quite different treatment for induction from auxin-nonrequiring calluses; from calluses T22 and XD6S2, auxin-nonrequiring calluses were induced by treatments with low concentrations of auxins (0.01–0.1 mg/liter of IAA or NAA) and high concentrations of synthetic auxins (10–100 mg/liter of NAA or 1–10 mg/liter of 2,4-D), respectively. No auxin-nonrequiring calluses were obtained when they were transferred directly to the basal medium (hormone-free medium).The transformation of auxin-requiring into auxin-nonrequiring calluses was fully reversible by treatment with 1 mg/liter of IAA at an early stage of subculturing on the basal medium, but not after prologed subcult