3种菊科入侵植物白花鬼针草、胜红蓟和假臭草的种子生物学特性比较研究

为探讨菊科入侵植物种子的繁殖特性,从种子的形态特征及种子萌发率等指标入手,对胜红蓟(Ageratum conyzoide)、白花鬼针草(Bidens alba)及假臭草(Eupatorium catarium)3种菊科入侵植物的种子特性进行比较研究。结果表明,白花鬼针草种子的冠毛芒最短及最少,沉降速度最大,种子的风媒传播能力最弱,但种子全身具长倒钩刺,主要通过人畜和货物等实现远距离散播。假臭草种子冠毛芒较胜红蓟的长和多,种子沉降速度较胜红蓟的小,其风媒传播能力较胜红蓟的强。白花鬼针草种子千粒质量、发芽指数、胚根、胚芽和胚轴均最大或最长,发芽率和发芽势也较高,其种子质量和种子活力为三者中最高。假臭草的千粒质量、胚根、胚芽和胚轴与胜红蓟无显著差异,但发芽势及发芽指数均显著高于胜红蓟,说明假臭草种子活力较胜红蓟的高。假臭草发芽率为三者中最小,这可能与其种子含水率(19%)高有关,高含水率隐含着种子在潮湿环境下易发生霉变。胜红蓟种子除了发芽率较高外,千粒质量、发芽势、发芽指数、胚根、胚芽和胚轴等指标均较小或大,反映其种子质量和活力较小。

Comparative Study on Seed Biological Characteristics of Three Invasive Compositae Species

In order to understand the reproductive characteristics of invasive plants in Asteraceae,the comparison study on morphological features and germination traits of seeds of Ageratum conyzoide,Bidens alba and Eupatorim catarium was conducted.The results showed that,the seed of Bidens alba had the shortest and least seeds crown awns,the fastest settle-ment velocity of the three kinds of Compositae seeds implying the weakest wind dispersal ability,but more and longer barbs all over,which helped to realize long -distance spreading through man,beast or goods.Eupatorium ca-tarium had longer and more seeds crown awns and slo-wer settlement velocity than Ageratum conyzoide,which implied the stronger wind dispersal ability than Agera-tum conyzoide.Bidens alba had the heaviest thousand grain weight,the largest germination index,the longest radicle,germ and hypocotyl,and higher germination percentage,germination potential,reflecting the highest seed quality and vigor of the three.Eupatorium catari-um had no significant difference in radicle,germ and hypocotyl with Ageratum conyzoide,but had significantly larger seed germination potential and germination index than Ageratum conyzoide,indicating that Eupatorium catarium had higher seed vigor than Ageratum conyzoide.Eupatorium catarium had the least germination rates of the three,probably caused by its high seed moisture content (19%),as high seed moisture content always means seed mildew in damp environment.In-stead of lower germination percentage,Ageratum conyzoide had lighter thousand grain weight,lower germination potential and germination index,shorter radicle,germ and hypocotyl,reflecting the lower seed quality and vigor than others.