In vitro micropropagation and long-term conservation of the endangered moss Splachnum ampullaceum

Protonema explants of Splachnum ampullaceum Hedw. were grown in vitro on 10 different mineral media with different sources and contents of nitrogen, in each case with or without added sucrose (30 g dm(-3)) and/or B5 vitamins. The cultures were maintained at day/night temperatures 24 +/- 4/20 +/- 2 degrees C and a 16-h photoperiod (irradiance of 25 mu mol m(-2) s(-1)). Sucrose had little or no effect on protonema diameter and bud number in nitrate-only media or in high-ammonium media but markedly reduced bud number in low-ammonium media. Sucrose markedly reduced one-year explant survival rate in the low-ammonium media. The presence of B5 vitamins in such media markedly improved one-year survival, suggesting that the best medium for long-term culture of Splachnum ampullaceum is a medium containing ammonium at relatively low concentration as ammonium phosphate or sulphate (e.g. Gamborg's B5 medium), with added B5 vitamins but without added sucrose.