The effects of explant and cytokinin type on regeneration of Prunus microcarpa

We investigated in vitro regeneration ability of Prunus microcarpa subsp. tortusa using various explants (root, cotyledon and hypocotyl pieces) and cytokinins [benzyladenine (BA), meta-Topolin (mT) and thidiazuron (TDZ)]. Sectioned cotyledon, root and hypocotyl pieces of in vitro grown seedlings were cultured on Nas and Read Medium (NRM) containing BA (7.5, 10, 12.5, 15 or 17.5 μM), mT (2.5, 5.0, 7.5, 10 or 12.5 μM) or TDZ (2.5, 5.0, 7.5, 10 or 12.5 μM). As a measurement of morphogenetic reaction, the ratios of regenerating explants and the numbers of primary adventitious shoots per regenerating explant were analyzed. Cotyledon explants exhibited higher regeneration ratios than hypocotyl explants, and the root explants were inappropriate for regeneration. Both BA and mT were effective on shoot regeneration but higher regenerating explant ratios were obtained when BA was used. In comparison with BA and mT, the effect of TDZ on enhancing explant regeneration ability was insignificant. Mean number of adventitious shoot per regenerating explant was between 1 and 4, and regenerating explant ratios were between 0% and 77%. The practical appliacations of the results are discussed.