In vitro propagation of Phebalium equestre and P. hillebrandii (Rutaceae)

Abstract

The endangered Phebalium equestre D. A. Cooke and the rare Phebalium hillebrandii J. H. Willis were propagated in vitro using shoot tips and nodal segments as explants. For each species, shoot proliferation was initiated on de Fossard MZZM (Medium levels of minerals, Zero auxins, Zero cytokinins and Medium levels of sucrose, growth factors, and amino acids) medium supplemented with 1 µM benzyladenine. Excised P. equestre shoots initiated roots when cultured on MZZM medium containing 60 µM 2,4-dichlorophenoxyacetic acid, while P. hillebrandii shoots required LZZL (Low levels of minerals, Zero auxins, Zero cytokinins and Low levels of sucrose, growth factors, and amino acids) medium containing 10 µM 2,4-D for maximal root initiation. Both species required transfer to MZZM medium without growth regulators after 2 wk to allow root initials to develop and grow. Plantlets were successfully transferred to soil with 80% survival after 2 mo.