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.

菊科（Asteraceae）阿尔达玛属（Aldama）的巴西样本尽管拥有增厚的地下结构，却无法进行营养繁殖；鉴于此类物种的繁殖策略相关数据匮乏，本项关于有性繁殖的研究具有重要意义。本研究旨在评估沙地阿尔达玛草（Aldama arenaria）、丝叶阿尔达玛草（A. filifolia）、线形叶阿尔达玛草（A. linearifolia）、粗壮阿尔达玛草（A. robusta）以及毛叶阿尔达玛草（A. trichophylla）的种子萌发最适温度。实验采用每日8小时光照周期（荧光灯提供光源），在20℃、25℃、30℃恒温以及15-35℃、20-30℃、20-35℃变温条件下对种子萌发情况进行评估，并对未萌发种子开展胚活力检测，同时还评估了丝叶阿尔达玛草的种子健康状况。结果显示，沙地阿尔达玛草、丝叶阿尔达玛草、粗壮阿尔达玛草及毛叶阿尔达玛草的种子最适萌发温度为20℃与25℃，线形叶阿尔达玛草的最适萌发温度为20℃。不建议在15-35℃的变温条件下萌发上述物种的种子。本研究涉及的6个真菌类群均未对丝叶阿尔达玛草的种子萌发产生影响。