Regeneration of Cladrastis lutea (Fabaceae) via somatic embryogenesis.
Immature embryos from 5 Cladrastis lutea (Michx.) K. Koch (yellowwood) trees were initially cultured on modified Schenk and Hildebrandt medium (SH) containing either 4.5, 9.0, 13.5 or 23 μM 2,4-D. One-third of the explants were transferred to SH medium supplemented with 25.0 μM NAA after 2 and 3 weeks respectively. The remaining explants were incubated on the initial 2,4-D containing media for 6 weeks. Groups of somatic embryos formed directly only at the proximal end of cotyledons; only a few formed as single embryos. The greatest numbers were formed from zygotic embryos explanted from 6-8 weeks post-anthesis and initially cultured on medium containing 9 or 13 μM 2,4-D. However, all treatments supported somatic embryogenesis. In the second year, explants were initially cultured on SH medium containing either 9.0, 13.5, or 23 μM 2,4-D and then transferred to SH medium containing 4.0 μM ABA after 2 or 3 weeks. ABA did not affect the development of somatic embryos. Six of 21 somatic embryos germinated on half-strength SH medium without growth regulators. Three entire plantlets were formed, but only one was established in soil.
Institute of Agriculture, Department of Ornamental Horticulture and Landscape Design, University of Tennessee, P.O. Box 1071, 37901, Knoxville, TN, USA.
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Trigiano