Establishment of a high-frequency regeneration system inCerasus humilis, an important economic shrub

Cerasus humilis is a species of small, perennial, drought-resistant and multipurpose deciduous shrub grown in arid and semi-arid conditions in northern China. In this study, an efficient protocol for the rapid micropropagation of C. humilis has been standardized using stem and/or leaf explants. Direct multiple shoot induction was observed when the stem explants were cultured on Murashige and Skoog (MS) medium supplemented with different plant growth regulators. The highest shoot induction was obtained when stem explants from adult trees were cultured on MS medium supplemented with 2.0 mg L−1 6-benzyladenine (6-BA) and 0.9 mg L−1 α-naphthaleneacetic acid (NAA). The leaf and stem explants cultured on MS medium with 1.0 mg L−1 6-BA and 0.6 mg L−1 NAA, and 0.5 mg L−1 6-BA and 0.8 mg L−1 NAA, respectively, produced the highest induction frequency of callus. Maximum proliferation of callus was observed on MS medium containing a combination of 0.5 mg L−1 6-BA with 0.6 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-d). Optimal shoots differentiated from callus were obtained on MS medium supplemented with 5.0mg L−1 6-BA and 0.9 mg L−1 NAA. In vitro rooting was achieved on half-strength (1/2) MS medium containing 0.5 mg L−1 NAA. Rooted plantlets were hardened under control conditions and successfully acclimatized under field conditions.