培养基质、储藏方式和盐度对三种海滨植物种子萌发的影响

Effects of substrate,storage way and salinity on the seed germination of three coastal plants

研究了培养基质、储藏方式和盐度对3种海滨植物互花米草(Spartina alterniflora)、盐地碱蓬(Suaeda salsa)和芦苇(Phragmites australis)种子萌发的影响,探索在潮间带环境下海滨植物种子萌发适应策略。结果表明:3种植物的干藏种子和湿藏芦苇种子随着盐度的升高,萌发率和萌发速率均显著下降,湿藏互花米草和盐地碱蓬种子在各盐度下萌发率和萌发速率差异不显著。各盐度-土培-干藏互花米草,中、高盐度-土培-干藏盐地碱蓬,土培各处理,中、高盐度-水培-干藏,高盐度-水培-湿藏芦苇种子萌发失败。湿藏提高了各盐度处理下土培互花米草,中、高盐度-水培和土培盐地碱蓬,淡水、中盐度-水培芦苇种子的萌发率和萌发速率。干藏互花米草种子在中、高盐度和土埋条件下种子的萌发受到抑制,限制了互花米草向高潮带与潮上带的扩展;而经常受潮水浸淹保持湿润的种子能抵抗高盐和泥沙沉积,导致互花米草种群逐步向低潮带方向发展;湿藏芦苇种子在淡水中萌发率和萌发速率最高,当潮上带盐度降低时,芦苇具有很强的竞争优势,但是对盐度和土埋敏感,限制了其向海的拓展;盐地碱蓬在中、高盐度和土培条件下萌发速率最高,快速萌发的适应策略和广适应性在盐地碱蓬占据高潮带和中潮带广大区域的过程中起到了重要的作用。

We describe effects of two substrate types,two storage ways and three salinity levels on germination characteristics of three dominant coastal plants,Spartina alterniflora,Suaeda salsa and Phragmites australis,with the goal to explore their strategies of seed germination in coastal environments.Increased salinity significantly lowered germination of all species after dry storage and that of P.australis after moist storage,whereas S.alterniflora and S.salsa after moist storage showed no significant difference.Seeds of S.alterniflora in all salinity treatments and S.salsa in median and high salinity treatments after dry storage and P.australis failed to germinate in the soil substrate.In water condition,only seeds of P.australis with dry storage in median and high salinity treatments and moist storage in high salinity failed to germinate.Moist storage had positive effects on total germination and germination rate of S.alterniflora in all salinity treatments and S.salsa in median and high salinity treatments in soil substrate,as well as those of S.salsa in median and high salinity treatments and P.australis in freshwater and median salinity treatments in water condition.Seed germination of S.alterniflora after dry storage was inhibited by median and high salinity,as well as soil burial,restricting its expansion towards high marsh.But moist seeds inundated by seawater frequently could better withstand high salinity and soil burial,leading to S.alterniflora to populate in the lower marsh.P.australis after moist storage obtained highest total germination and germination rate in freshwater,which was thought to give P.australis a competitive advantage in salt marsh conditions that received freshwater input;nevertheless,spreading toward sea of P.australis was inhibited by salinity and soil burial.Seeds of S.salsa obtained highest germination rate in both saline and buried conditions,showing rapid germination strategy and widely adaptation,which was responsible for occupying the middle and high marsh in the coastal environments.