Adventitious Bud Formation from Mature Embryos of Picea chihuahuana Martínez, an Endangered Mexican Spruce Tree

Abstract

Zygotic embryos of Picea chihuahuana MartõÂ nez were cultivated in vitro to determine the time of organogenic competence and to maximize adventitious bud induction. The induction medium consisted of modi®ed B5 substrate supplemented with N 6 -benzyladenine (with or without naphthalene acetic acid) or kinetin (with or without 2-4, dichlorophenoxyacetic acid) at dierent concentrations and induction times. The minimum induction time required for bud formation was 14 d with kinetin and 17 d with N 6 -benzyladenine. After induction embryos were transferred to the proliferation medium (modi®ed 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 eective treatments were 3 and 5 mg l À1 kinetin or N 6 -benzyladenine which produced ®ve to seven buds per embryo. The largest shoots were subjected to rooting trials with pulses of dierent 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 N 6 -benzyladenine. # 2000 Annals of Botany Company

Priming effects on seed germination of two perennial herb species in a disturbed lava field in central Mexico

“…For the priming treatments, seeds of P. roseus were washed for up to 10 min in Tween 80 polyoxyethylene sorbitan monolaurate (Lipoquimia, Mexico) (three drops in 50 ml of distilled water) and then soaked for 20 min in Microdyn (colloidal silver solution at 35%, Mercancías Salubres S.A. de C.V., Mexico: three drops in 50 ml of distilled water). Finally, seeds were disinfected in 70% ethanol and washed in 50 ml of sodium hypochlorite solution (1:3 v/v) for 20 min (López-Escamilla et al ., 2000).…”

MORFOGÉNESIS IN VITRO DE Pseudotsuga menziesii VAR. glauca

“…El H 2 O 2 desinfectó efectivamente las semillas, sin embargo, la respuesta que tuvieron los embriones al medio de cultivo, no fue positiva. Los embriones maduros de Picea chihuahuana Martínez (López-Escamilla et al,2000) y Pseudotsuga menziesii (Galindo, 2000;Monjarás, 2004) forman brotes adventicios cuando se cultivan en medios con reguladores de crecimiento. En este trabajo, el medio M S sin reguladores promovió una germinación más rápida de los embriones (Figura 1).…”

“…H 2 O 2 effectively disinfected the seeds; however, the response of the embryos to the medium was not positive. Mature embryos of Picea chihuahuana Martínez (López-Escamilla et al, 2000) and Pseudotsuga menziesii (Galíndo, 2000;Monjarás, 2004) formed adventitious shoots when cultured on media with growth regulators. In this study, the MS medium without regulators promoted faster embryo germination (Figure 1).…”

Morfogénesis in vitro de brotes adventicios del pinabete mexicano Pseudotsuga menziesii

“…La formación de brotes adventicios siguió el patrón descrito (Cheah y Cheng 1978;Yeung et al, 1981;Villalobos et al, 1985;von Arnold y Grönroos, 1986;López et al, 2000) que inició con la reactivación mitótica de una o dos células que fomaron, en orden secuencial, promeristemoides, meristemoides y luego el domo apical integrado por el meristemo y los primordios foliares.…”