Mutagenesis and in vitro culture of Tillandsia fasciculata Swartz var. fasciculata (Bromeliaceae)

Abstract

The genus Tillandsia (Bromeliaceae) has very few variegated species, and cultivars with chlorophyll-deficient variegation are especially rare. With the objective of inducing chlorophyll-deficient leaf variegation, seeds of Tillandsia fasciculata var. fasciculata were treated with gamma radiation, combined gamma and thermal neutron radiation or by chemical mutagenesis with ethyl methanesulfonate (EMS). Wild type, albino, yellow, yellowish-green and variegated phenotypes were obtained in the subsequent M 0 generation. These variegated seedlings were either sectorial or mericlinal chimeras, consequently the variegation of these seedlings was lost as they grew older. Gamma radiation at 21 kR and 27 kR produced the highest percentage of variegated seedlings (4.4%). The highest percentage of seedlings with chlorophyll-deficient leaves was 8.4% with 27 kR gamma radiation, and 15.8% with 1.2% EMS. Radiation and chemical mutagenesis caused chlorophyll-deficiency mutations in one or more of the histogenic layers: LI, LII, LIII. Wild types had greater total chlorophyll a, b and total chlorophyll than mutant phenotypes. Most of the yellow and yellowish-green seedlings multiplied in a solid half-strength MS medium with equimolar 0.3 or 0.5 μM BA and IBA. The yellowish-green seedlings were able to grow photoautotrophically while the yellow ones were not. This is one of the first reports on the mutagenesis of a Tillandsia species. Stable periclinal chlorophyll-deficient chimeras of Tillandsia species can likely be obtained via mutagenesis if large numbers of seeds are treated with a suitable mutagen.