ISHS Acta Horticulturae 616: I International Symposium on Acclimatization and Establishment of Micropropagated Plants
NOVEL METHODS IN MICROPROPAGATION |
| Authors: | J.E. Preece, P.E. Read |
| Keywords: | Bud encapsulation, juvenility, shoot forcing |
| Abstract:
The focus of this paper is on two novel methods for micropropagation, forcing softwood shoots from large stem sections and encapsulation of buds and shoot tips for storage and facilitation of Stage IV, acclimatization. Neither method is being used widely by commercial micropropagation laboratories. Branches are excised from within the cone of juvenility of woody plants that were originally propagated from seed. The branches are cut into sections 30-50 cm long and placed horizontally in flats or benches filled with perlite. Irrigation must be done with care to avoid water contacting the stem segments or new softwood shoots. The softwood shoots are excised, surface disinfested and used as explants. If the softwood shoots are to be used as macrocuttings, forcing is best under intermittent mist. However, forcing in mist will result in microbial contamination if micropropagation is the goal. Alginate gel is used to encapsulate somatic embryos to produce synthetic seeds. The same gel matrix can be used to encapsulate buds and shoot tips from Stage II proliferating cultures. The encapsulated buds can be stored under refrigerated conditions or dehydrated and placed in liquid nitrogen. Additionally, shoots and roots can grow from the encapsulated shoot tips and buds and these can be transplanted to a greenhouse medium for acclimatization. Because of the nutrient salts and sucrose in the gel matrix, the incorporation of fungicides into the gel has reduced fungal growth during Stage IV and has increased the percent survival. | |
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