An effective route for the micropropagation of Medinilla formosana through ovary culture in vitro

Abstract

Medinilla formosana Hayata, a beautiful endangered shrub of the family Melastomataceae endemic in Taiwan of China, is recalcitrant for micropropagation in vitro until now. And tissue browning after cutting generally occurred in the tissue culture of Medinilla species was considered to be the greatest obstacle. To avoid the serious cut-browning, immature ovaries in 0.3 cm diameter of M. formosana were taken as initial explants in this study, and its aseptic plantlets were obtained for the first time. The highest survival level (12.7 plantlets per ovary) after 3 months of culture were observed on 1/2 MS supplemented with 0.5 g l-1 active carbon and 0.4 g l-1 casein hydrolysate (pH 5.5). Furthermore, β-mercaptoethanol proved to be an effective inhibitor for its browning response of M. formosana in vitro. And 1/2 MS media supplemented with 6.67 µM BA, 0.11 µM NAA, 0.5 mM β-Met and 0.2 g l-1 AC proved appropriate for its multiplication. Finally rooted plantlets were transplanted into the greenhouse after acclimatization, and the micropropagation system of M. formosana was successfully established. This report first details an efficient method for the in vitro micropropagation of Medinilla plants.