Development of micropropagation protocols forCocos nucifera has progressed slowly. Activated charcoal is included in the culture medium of each protocol, mainly to prevent tissue browning. Charcoal production procedures can affect the properties of different brands. In this study, eight types of activated charcoal were evaluated for their effects on free 2,4-dichlorophenoxyacetic acid level, pH, conductivity, and osmolarity of the culture medium and on the frequency of embryogenic callus induction. Moreover, the effect of particle size of the optimum charcoal type on embryogenic callus development was also studied. Charcoal type had a significant effect on (Y3) culture medium properties. Free 2,4-D was highest in Reactivos y Productos Químicos Finos-containing medium and pH was lowest in MERCK-containing medium. Charcoal type also influenced embryogenic callus induction, with acid washed for plant cell and tissue culture-, DARCO-and United States Pharmacopeia-containing media promoting *60% embryogenic callus, but with different optimal 2,4-D concentrations. Particle size profiles varied among all charcoal types, although small particle fraction (\38 lm) was abundant in all. Use of small particle fractions produced higher frequencies of embryogenic callus (70%) than either large particle or whole charcoal fractions.

A new type of bioreactor system for plant micropropagation is described that incorporates a number of features specifically designed to simplify its operation and reduce production costs. The BioMINT unit is a mid-sized (1.2 L) reactor that operates on the principle of temporary immersion. It is built of polypropylene and is translucent, autoclavable, and reusable. It consists of two vessels, one for the plant tissues and the other one for the liquid culture media coupled together through a perforated adaptor piece that permits the flow of the liquid media from one vessel to the other. This flux is driven by gravity through a see-saw movement provided by equipment (SyB) consisting of electric motor powered platforms that change position. The structural simplicity and the modular and independent nature of the bioreactors simplify their operation and reduce the amount of hand labor required for transfers, thereby reducing the cost of the whole micropropagation process.

No abstract

No abstract

Somatic embryogenesis is a very efficient way to propagate economically important plants; however, not all genotypes within a species can be propagated using this method, as a combined effect of both genetic and epigenetic mechanisms may be involved in the response. The aim of the present study was to perform a comparative analysis of the genetic differences through amplified fragment length polymorphism (AFLP) and the epigenetic differences through methylation-sensitive amplified polymorphism (MSAP) of two Agave fourcroydes clonal lines, one highly embryogenic (K33) and the other non-embryogenic (K7). Genetic and epigenetic variabilities existed within each clonal line; however, the polymorphic profiles from the two marker systems allowed us to clearly distinguish the two clonal lines before somatic embryogenesis induction. During the induction, the changes detected were mainly 1) unmethylated fragments in the initial explants that were methylated during induction (methylation events) and 2) fragments with different methylation states in the initial explant that were unmethylated in some stages of the process (demethylation events). K33 showed greater dynamism in relation to methylation/demethylation events, while K7 presented the methylation events in a more constant range and at higher levels during all process.