Annals of Botany 86: 921-927, 2000
© 2000 Annals of Botany Company
Adventitious Bud Formation from Mature Embryos of Picea chihuahuana Martínez, an Endangered Mexican Spruce Tree
Laboratorio de Cultivo de Tejidos Vegetales, Jardín Botánico del Instituto de Biología, Universidad Nacional Autónoma de México (UNAM), Apdp. Post. 70-614, CP 04510, Distrito Federal, México Facultad de Ciencias, (UNAM), México, D.F., 04510, México
Received: 23 February 2000 ; Returned for revision: 2 May 2000 . Accepted: 15 June 2000
Zygotic embryos of Picea chihuahuana Martínez were cultivated in vitro to determine the time of organogenic competence and to maximize adventitious bud induction. The induction medium consisted of modified B5 substrate supplemented with N6-benzyladenine (with or without naphthalene acetic acid) or kinetin (with or without 2-4, dichlorophenoxyacetic acid) at different concentrations and induction times. The minimum induction time required for bud formation was 14 d with kinetin and 17 d with N6-benzyladenine. After induction embryos were transferred to the proliferation medium (modified B5 substrate with 50% of its components and without growth regulators) for 30 d. The subsequent buds were transferred every 15 d to Schenk and Hildebrandt medium at half its concentration without growth regulators. The most effective treatments were 3 and 5 mg l-1kinetin or N6-benzyladenine which produced five to seven buds per embryo. The largest shoots were subjected to rooting trials with pulses of different concentrations of indole butyric acid resulting in only one bud developing a root. Histological analysis revealed clusters of three to four cells that became more evident as induction time increased. Kinetin promoted the development of an organized structure prior to adventitious buds formation sooner than N6-benzyladenine. Copyright 2000 Annals of Botany Company
Competence, plant tissue culture, micropropagation, Picea chihuahuana, endangered species, spruce