Seed germination of Brazilian Aldama species (Asteraceae)

Brazilian samples from the Aldama genus (Asteraceae) could not propagate vegetatively despite their thickened underground system; thus, this study on sexual propagation is critical given the lack of data on reproductive strategies for such species. The aim for this research was to assess the optimal temperature for Aldama arenaria, A. filifolia, A. linearifolia, A. robustaand A. trichophylla seed germination. Seed germination was evaluated at the constant temperatures 20, 25 and 30 °C and the alternating temperatures 15-35, 20-30 and 20-35 °C with an 8-h daily photoperiod, using fluorescent-lamp. The ungerminated seeds were evaluated for embryo viability. The A. filifolia seed health was also evaluated. The optimal temperatures for germination are 20 and 25 °C for Aldama arenaria, A. filifolia, A. robusta and A. trichophylla seeds and 20 °C for A. linearifoliaseeds. The alternating temperature 15-35 °C is not recommended for germinating seeds from these species. The six fungi taxa studied herein did not affect A. filifolia seed germination.

奥德玛属（Aldama，菊科Asteraceae）的巴西样本虽具备肥厚的地下结构，却无法进行营养繁殖；鉴于此类物种生殖策略相关研究数据的匮乏，本项针对其有性繁殖的研究具备重要意义。本研究旨在测定沙地奥德玛（Aldama arenaria）、细叶奥德玛（A. filifolia）、线形叶奥德玛（A. linearifolia）、粗壮奥德玛（A. robusta）以及毛叶奥德玛（A. trichophylla）的种子萌发最适温度。实验采用荧光灯提供光照，设置每日8小时的光周期，分别在20℃、25℃、30℃的恒温条件以及15-35℃、20-30℃、20-35℃的变温条件下对种子萌发情况进行评估，并对未萌发种子的胚活力进行检测，同时测定了细叶奥德玛种子的健康状况。结果表明，沙地奥德玛、细叶奥德玛、粗壮奥德玛与毛叶奥德玛的种子最适萌发温度为20℃与25℃，线形叶奥德玛种子的最适萌发温度为20℃。本研究不建议采用15-35℃的变温条件对上述物种的种子进行萌发培养。本次研究涉及的6个真菌类群并未对细叶奥德玛的种子萌发产生影响。