Plant regeneration from mesophyll protoplasts of the tree legume Pithecellobium dulce benth

Abstract

Conditions were developed for the isolation, culture and regeneration of mesophyll protoplasts of the tree legume, Pithecellobium dulce Benth. The presence of 2,4-dichlorophenoxyacetic acid (2,4-D) was essential to induce initial cell divisions and addition of naphthaleneacetic acid (NAA) improved the response. Sustained division and cell colony formation were achieved from the protoplasts cultured in a modified KM8P medium containing 2,4-D (2.3 μM), NAA (3 μM) and benzyladenine (BA) (2.3 μM). Dilution of the osmotica included in the protoplast culture medium was necessary to induce sustained proliferation of the protoplast-derived cells. Differentiation of shoots from the protoplast-derived calli occurred on Murashige and Skoog (MS) medium supplemented with BA (5 μM) and indole-3-acetic acid (1 μM). Omission of 2,4-D from the culture medium, after the initial 2 weeks of protoplast culture, was obligatory to induce shoot morphogenesis.