ABSTRACT
The induction and improvement of in vitro rhizogenesis of microshoots of Prosopis chilensis (Mol.) Stuntz and Nothofagus alpina (Poep. et Endl. Oerst.) were compared using Agrobacterium rhizogenes (Ar) versus indole-3-butyric acid (IBA) in the culture media. Microshoots of P. chilensis (1-2 cm length), coming from in vitro grown seedlings, were cultivated in a modified Broadleaved Tree Medium (BTMm) containing half salt concentration of macronutrients and 0.05 mg x L(-1) benzilaminopurine (BAP). After 30 days, microshoots with 2-4 leaves were selected and cultured in BTMm-agar in presence or abscense of Ar and in combination with IBA. For N. alpina, the apical shoots with the first 2 true leaves, from 5 weeks old seedlings, were cultured in the abovementioned medium, but with 0.15 mg x L(-1) of BAP. After 2 months, microshoots with 2-3 leaves were selected and cultured in BTMm-agar, supplemented with 5 mg x L(-1) IBA or in liquid BTMm on perlite and, in the presence or absence of A. rhizogenes (Ar) and in combination with 3 mg x L(-1) IBA. Rooting in P. chilensis reached 100.0% when Ar infection was produced in the presence of IBA, increasing both, the number and dry weight of roots. In N. alpina, 90.0% of rooting efficiency was obtained when Ar infection was produced in liquid culture and in the absence of auxin.
Subject(s)
Trees/growth & development , Indoleacetic Acids , Embryonic Induction/drug effects , Prosopis/growth & development , Plant Roots/growth & development , Rhizobium/physiology , Trees/drug effects , Trees/microbiology , Plant Shoots/drug effects , Plant Shoots/growth & development , Plant Shoots/microbiology , Cells, Cultured , Cell Differentiation/drug effects , Cell Differentiation/physiology , Plant Physiological Phenomena/drug effects , Culture Media/chemistry , Culture Media/pharmacology , Prosopis/drug effects , Prosopis/microbiology , Plant Roots/drug effects , Plant Roots/microbiologyABSTRACT
El Li+ tiene la capacidad, en embriones sanos, de inducir la formación supernumeraria de estructuras cefálicas y de revertir las deficiencias del eje neural que se evidencian en embriones expuestos a la luz ultravioleta. Por otra parte, la hidrólisis de los fosfoinositodos de la membrana se ha implicado en los aumentos de Ca2 que proceden a los eventos que se suceden durante la fertilización y el desarrollo embrionario y el Li+ impide que los niveles de fosfoinositol (4,5), bifosfato retornen a sus niveles normales. La conclusión a la cual se debe llegar es que el Li+ altera la reespecificación dorsoanterior de los embriones y que esto debe depender de su capacidad de interferir con el ciclo de los fosfoinositidos. Estas observaciones tienen relevancia particular puesto que los efectos específicos del Li+ sobre el ciclo de los fosfoinositidos permiten suponer que alguno de los intermediarios de este ciclo debe jugar un papel importante en la diferenciación y especificación dorsoanterior del embrión. Es preocupante el hecho de que estos efectos pueden obtenerse utilizando concentraciones de Li+ similares a las usadas terapéuticamente en el manejo de las enfermedades maniacodepresivas