Plant Cell, Tissue and Organ Culture 30: 247-249, 1992. 0 1992 Kluwer Academic Publishers. Printed in the Netherlands. Micropropagation note In vitro multiplication of Vriesea fosteriana H. Mercer & G.B. Kerbauy Laboratory of Plant Cell Biology, Department of Botany, University of S~o Paulo, C.P. 11461, 05499-S~o Paulo, SP, Brazil Accepted in revised form 17 February 1992 Key words: Bromeliaceae, endangered plant, micropropagation, shoot regeneration Abbreviations: BA- 6-benzyladenine, FAA- 50-formalin: glacial acetic: ethanol: water, IBA- indole- 3-butyric acid, KC-Knudson C, MS-Murashige & Skoog, 1/2 MS-half strength Murashige & Skoog, NAA- a-naphthaleneacetic acid Vriesea fosteriana L.B. Smith, a bromeliad with highly ornamental qualities, occurs in a restricted area of south-eastern Brazil. This species has especially attractive and characteristic leaf pig- mentation patterns. Harvesting of the plant for sale has been destructive, and widespread and continued use will hasten extinction (Leme 1984). Bromeliads are frequently propagated by seeds or by division of lateral shoots, although both methods present certain disadvantages (Jones & Murashige 1974). In subfamily Tillan- dsioideae, which includes the genus Vriesea, only one or two offshoots are formed in the post- flowering stage (Mekers 1977). However, appli- cation of tissue culture to clonal propagation of Tillandsia cyanea was recently reported (Pierik & Sprenkels 1991). The present paper describes conditions for multiplication and growth of Vri- esea fosteriana. Mature seeds of Vriesea fosteriana were dis- infested by washing with 70% ethanol for 3 min, then in 20% commercial bleach (5% of NaOCI) for 40min, and were rinsed 3 times in sterile distilled water. Two seeds were inoculated into each 25 × 150 mm metal-capped glass tube con- taining 20 ml of basal medium. Knudson (1946) (KC) and Murashige & Skoog (1962) full strength (MS) and half strength (1/2 MS) were used as basal media, with KC modified by the addition of MS micro-nutrients. Comparative ef- fects of agar-gelled (0.8% W/V Difco Bacto- agar), and stationary liquid media were studied. pH was adjusted to 5.8 prior to autoclaving. The 30-day-old seedlings were transferred (1 per tube) to gelled KC media supplemented with NAA (0.54, 1.1, 2.2, 3.2, 4.3 or 5.4 ~M) alone or NAA (0.54, 2.7 or 5.4 txM) in combination with BA (8.9, 22.5 or 44.4 IxM). Subsequent transfers of seedlings to stationary liquid KC medium with (2.7 txM) NAA and (8.9 IxM) BA were tried. For experiments on bud regeneration from leaf explants, entire leaves with a minimum length of 2 cm were removed from aseptically- grown seedlings and re-cultured (1 per tube) on gelled KC medium with added NAA, in combi- nation with BA at the same concentrations as described for seedlings. Subsequent transfer of leaf explants to stationary liquid KC medium supplemented with 2.7 ~M NAA and 8.9 txM BA was tried. The clusters of shoots obtained from seedling and leaf cultures were cultivated for 3 months on gelled KC medium supplemented with 0.54 ~M NAA for re-establishment of apical growth. For rooting, shoots ca. 2 cm tall were transferred (10 per flask) to 90ml wheaton flasks containing 30 ml of gelled KC medium with 1.1 IxM NAA. All cultures were maintained at 26---I°C in a