Pineapple (Ananas comosus L. Merr) micropropagation in temporary immersion systems

A procedure for the mass propagation of pineapple plants (Ananas comosus L. Merr) using a temporary immersion technique is described. This procedure involved three distinct phases in the automated temporary immersion system: shooting, bud differentiation and elongation. To establish this protocol, we used in vitro shoots obtained from established liquid culture as starting materials. Three culture methods (solid, liquid and temporary immersion) were compared. Temporary immersion increased the multiplication rate and fresh and dry weight after 42 days. Conventional micropropagation (liquid medium) and temporary immersion were compared in combination with paclobutrazol. Paclobutrazol promoted the formation of compact bud clusters with limited leaf development. The highest multiplication rate (106) was found when ex-plants were cultured in shooting medium (MS+2.1 mg/l BA+0.3 mg/l NAA) supplemented with 1 mg/l PB for 7 weeks. A 10-l temporary immersion bioreactor was used to test two approaches during elongation stage: reduction of the shoot-formation period or decrease of the initial number of explants. The highest number of competent and uniform plants (191.8 plant/l) was achieved when shoots were cultured for 4 weeks in shooting medium supplemented with PB.