Sowing pyrenes under aseptic conditions enhances seed germination of Ilex brasi liensis, I. pseudoboxus and I. theezans (Aquifoliaceae)

Abstract

Seeds of Ilex species are individually enclosed by a woody endocarp, forming a dispersal unit termed a pyrene. Embryos are undeveloped when fruits reach maturity. As a consequence, germination is low even after several months under proper conditions. In the present study, we present reliable and reproducible techniques that enhance seed germination of Ilex brasiliensis, I. pseudoboxus and I. theezans by aseptically sowing whole pyrenes. The highest germination percentages (53-92%) were reached by in vitro culturing whole pyrenes on solidified (0.65% agar) quarter-strength Murashige and Skoog medium with 3% sucrose and 0.1 mg l-1 zeatin, and incubating in a growth room at 27 ± 2°C with a 14-hour photoperiod. Thus, the in vitro culture of whole pyrenes constitutes an easy and efficient technique to obtain quick germination of these Ilex species and may be an alternative to embryo rescue. Rapid progress in the application of this method to breeding and preservation programmes of Ilex species is expected.