A. ulvaceus plants were supplied by local aquarium plant
trader. The plants were maintained in water-filled tanks
until flowering. Mature flowers were cross-pollinated
with fresh pollens from plants of the same species. Spikes
with seed-bearing follicles were disinfected in 70 %
(v/v) ethanol for 30 s, followed by 0.4 % (v/v) sodium
hypochlorite for 20 min. Seeds were subsequently
removed from follicles and germinated on basal MS
medium (Murashige and Skoog 1962) (Duchefa Biochemie
B. V.) containing 3 % (w/v) sucrose (Fisher Scientific)
and 0.35 % (w/v) Phytagel (Sigma-Aldrich). To prevent
desiccation, seeds were submerged in liquid MS medium.
All media were adjusted to pH 5.8 and autoclaved at
121 °C for 15 min. Cultures were maintained at 25 ± 1 °C
under a 16 h photoperiod (40 μmol m−2 s−1) provided
by cool-white fluorescent lamps (Akari TLD36W/54).
In vitro-raised plantlets were subcultured at 21-day intervals
into fresh MS basal medium.