阿拉善荒漠几种典型灌木种子水分响应与繁殖对策研究

本文以阿拉善荒漠分布的沙冬青(Ammopiptanthus mongolicus)、梭梭(Halox-ylon ammodendron)、红砂(Reaumuria soonorica)、阿拉善沙拐枣(Calligonum alaschanicum)、膜果麻黄(Ephedra przewalsetina)、绵刺(Potaninia mongolica)和四合木(Tetreana mongol-ica)等灌木为研究对象,以种子吸胀过程中对水分的吸收速度和水分利用效率作为对水分的响应特性。研究结果表明:所供实验的各种灌木种子吸胀所需时间顺序依次为:梭梭<四合木<绵刺<膜果麻黄<红砂<阿拉善沙拐枣<沙冬青,与之相对应的种子千粒重为沙冬青>阿拉善沙拐枣>红砂>梭梭>四合木>膜果麻黄>绵刺,种子千粒重与吸胀时间呈极显著的正相关关系;吸胀过程中水分吸收速度和水分利用效率分别是阿拉善沙拐枣>沙冬青>四合木>红沙>梭梭>绵刺>膜果麻黄,梭梭>膜果麻黄>绵刺>四合木>阿拉善沙拐枣>沙冬青>红沙。响应于荒漠水分的变化,荒漠灌木可分为对水分敏感性植物和迟钝性植物。对水分敏感性植物,繁殖对策表现为典型的r-对策,千粒重较小,对水分利用效率较高,如绵刺、梭梭等,对水分迟钝性植物,繁殖对策为典型的k-对策,千粒重较大,水分利用效率较低,如阿拉善沙拐枣和沙冬青等。响应于荒漠环境为极度胁迫下的易变环境,水分敏感的植物对荒漠植被的稳定具有重要贡献,响应于相对稳定时间尺度内,水分迟钝植物对荒漠植被构建起着关键作用。这种r-对策和k-对策荒漠灌木对水分不同的利用方式和繁殖方式,既能在干旱多变的气候环境变化下保持一定的荒漠景观植被,又能在稳定气候环境下保持另一种荒漠景观植被,从而确保荒漠地表环境的稳定。

Seed Water Response and Propagation Strategies of Several Typical Shrubs in Alashan Desert

This research was about the studies of Ammopiptanthus mongolicus,Haloxylon ammodendron,Reaumuria soonorica,Calligonum alaschanicum,Ephedra przewalsetina,Potaninia mongolica,Tetreana mongolica and so on which are distributein Alashan desert,Inner Mongolia.Water absorbingprocess of several shrub seeds were investigated,seed water absorbing speedand water utilizing rate were chosen as the indexes of theirresponsing characters towater.The results indicatedthat the times of the seed imbibitionrequiringwas :Haloxylon ammodendronAmmopiptanthus mongolicus>Tetreana mongolica>Reaumuria soonoric>Haloxylon ammodendron >Potaninia mongolica>Ephedra przewalsetina,Haloxylon ammodendron> Ephedra przewalsetina>Potaninia mongolica>Tetreana mongolica >Calligonum alaschanicum>Ammopiptanthus mongolicus>Reaumuria soonorica.Responsing to the desert water change,desert shrubs were dividedinto watersensitiveplant andwater unsensitiveplant.To water sensitivity plant,propagation strategies behaved typical r-strategies,1000-Grain Weighwas smaller,water utilizing efficiency was higher,such as Potaninia mongolica,Haloxylon ammodendron.To water unsensitiveplant,propagation strategies behaved typical k-strategies,1000-Grain Weighwas larger,water utilizing efficiency was lower,such as Calligonum alaschanicum,Ammopiptanthus mongolicus.Desert environmentwas variableunder extremely enforcement,water sensitive plantmostly contribute to stabilization of desert vegetation.Within relativestable stage,the reaction of waterunsensitivek-strategies plantshad key action indesert vegetation construction.TheThe differentutilizing manner and propagation mannerofwater r-strategies and water k-strategies desert shrubs,keepsa certain desert landscape under dry andchangeable climate,and keeps anotherdesert landscape under stabilization climate,consequently ensured overground environmentstabilization of desert.