斑叶蒲公英种子萌发特性研究

摘要

In order to understand the seed germination characteristics of T.variegatum,we used apomixes T.variegatum (tetraploid) as materials to study the influence of seed germination by pollination,pappus,seed soaking and temperature.The results showed that pollination had significant influence on seed germination potential and germination rate.The germination percentage of pollination treated seeds was 40％ higher than that of unpollination treated ones.Pollination treated seeds belonged to the rapid "opportunism" germination strategies; but unpollination treated seeds belonged to low "bet hedging" germination strategies.The germination for seeds lacking a pappus was 16％ lower than that of the control seeds (with an intact pappus),and the seeds lacking a pappus required longer time to germinate.Seed soaking had different effects on germination rate,seed soaking for 12h had the highest germination rate,seed soaking 48h or more made the germination rate and germination potential reduced.But for unpollination treated seeds,seed soaking could promoe germination.Seed germination of T.variegatum was suppressed by low temperatures(＜5℃) and high temperatures(＞30℃),10～20℃ was the optimum temperature,and had the highest seed germination (＞60％).Pollination,pappus and seed soaking promotive the germination rate,10～20℃ is the optimum temperature for T.variegatum germinaion.%以无融合生殖的四倍体斑叶蒲公英为材料,研究其种子萌发特性.考察授粉与否、冠毛有无,浸种时间、不同萌发温度和光照处理等对斑叶蒲公英种子萌发特性的影响.结果表明:经过授粉处理的蒲公英种子比未经过授粉处理的种子发芽率高40％.授粉与否产生不同萌发类型,授粉种子属于爆发型的机会主义萌发策略,而未授粉种子属于低萌型的谨慎萌发策略.缺少冠毛的种子发芽率比有冠毛种子低16％,并需更长时间萌发.浸种时间长短对发芽率影响不同,浸种12h种子发芽率最高,浸种超过48h,种子发芽率、发芽势均降低.而对未授粉处理的种子,浸种却有促进发芽率和发芽势的作用.斑叶蒲公英种子在高温(＞30℃)及低温(＜5℃)情况下,种子萌发均受到明显抑制,萌发温度为10～20℃时,种子具有最大的发芽率,均在60％以上.可见,授粉、冠毛以及短时间浸种对种子萌发均有促进作用,10～20℃为斑叶蒲公英的最适萌发温度.