喀斯特山区乡土灌木种子吸胀与萌发特性

Seed Water Imbibition and Germination Characteristics of Shrubs in Karst Areas

为从萌发对策角度探讨喀斯特地区乡土灌木的环境适应性,探索了贵州喀斯特山区广泛分布的白刺花、刺槐、胡枝子、马桑和火棘5种灌木种子吸涨过程中的吸水特性和萌发特性。结果表明:5种灌木种子吸胀时间为火棘>马桑>白刺花>刺槐>胡枝子,种子千粒重为刺槐>白刺花>火棘>胡枝子>马桑,与水分利用效率呈显著正线性关系(P<0.05);吸胀过程中水分吸收速度和水分利用效率分别是刺槐>胡枝子>白刺花>马桑>火棘,胡枝子>刺槐>白刺花>马桑>火棘,与之相关的种子最终萌发率、平均萌发时间和开始萌发时间分别为刺槐>马桑>胡枝子>火棘>白刺花,火棘>马桑>白刺花>刺槐>胡枝子,马桑>火棘>白刺花>刺槐>胡枝子,种子萌发率与水分吸收速度和水分利用效率均具有显著正相关性(P<0.05),种子水分吸收速度与种子平均萌发时间呈显著负相关关系(P<0.05)。结论:5种灌木种子吸胀与萌发对水分的响应不同,刺槐和胡枝子属于水分敏感性植物,其萌发对策为爆发型;白刺花、火棘和马桑属于水分迟钝性植物,其萌发对策为稳定型。

In order to explore the environmental suitability of shrubs from aspects of germination strategy, the seed water imbibitions and germination characteristics of Sophora davidii, Robinia pseudoacacia,Lespedeza bicolor,Coriaria nepalensis and Pyracantha fortuneana were studied,which widely distributed in Guizhou Karst mountain areas.The results showed that the imbibition time of five shrub seeds requiring was P.fortuneana〉C.nepalensis〉S.davidii〉R.pseudoacacia〉L.bicolor. Corresponding 1000-grain weight was R.pseudoacacia〉S.davidii〉P.fortuneana〉L.bicolor〉C.nepalensis.Water absorbing speed and water utilizing efficiency were：R.pseudoacacia〉L.bicolor〉S.davidii〉C.nepalensis〉P.fortuneana,L.bicolor〉R.pseudoacacia〉S.davidii〉C.nepalensis〉P.fortuneana. Final germination rates, mean germination time and start germination time were R.pseudoacacia〉 C. nepalensis 〉 L. bicolor 〉 P.fortuneana 〉 S. davidii, P.fortuneana 〉C.nepalensis〉S.davidii〉R.pseudoacacia〉L.bicolor,C.nepalensis〉P.fortuneana〉S.davidii〉R.pseudoacacia〉L.bicolor.1000-grain weight and water utilizing efficiency showed significant negative correlation（P〈0.05）and final germination had a significant positive correlation（P〈0.05）with 1000-grain weight and water utilizing efficiency.By a comprehensive analysis,germination strategies of five shrub seeds showed different responses to water,R.pseudoacacia and L.bicolor to the relative sensitivity of plants to water, to the plant stable in Karst mountain areas played an important role;S.davidii, P.fortuneana and C.nepalensis belonged to the water unsensitive plant,played a key role in vegetation composition and population development.