【摘要】 为了探明嵩草属牧草种子的繁殖特性,提高嵩草属牧草种子的发芽率,利用扫描电镜,对7种采自西藏的嵩草种子的形态特征及其解剖特征进行了观察。用不同浓度的赤霉素、聚乙二醇、硫酸、氢氧化钠对嵩草种子做了化学处理,并对其种皮特征也进行了电镜观察。结合发芽试验,初步分析认为:嵩草属牧草种子在自然条件下萌发率极低,可能是由于嵩草属种子的综合性休眠。种子小、果皮坚硬致密、外覆光滑且厚的角质层是主要原因。坚硬致密的果皮虽有利于嵩草属种子抵御严寒和外力破坏,但同时也使胚和胚乳不易获得足够的水和氧气,并阻碍胚根和胚芽穿破保护组织,限制了种子的萌发。一定浓度的氢氧化钠处理种子能均匀去掉果皮角质层,甚至破坏果皮最外层大型厚壁细胞,增大细胞间隙,使中间纵向致密组织变得疏松,让水分和氧气易于进入种子,从而提高发芽率。更多还原

【Abstract】 In order to investigate the reproductive characteristics of Kobresia pasture seeds and promote the germination rates,the morphological and anatomical characteristics of seven kinds of Kobresia pasture seeds from Tibet and the characteristics of seed capsules treated with gibberellin,PEG,sulfuric acid and sodium in different concentrations were observed by SEM.Combined with germination test,the preliminary results showed that the low germination rates of Kobresia seeds under natural conditions were due to their comprehensive dormancy.The main reason maybe that the seeds are small and their skins are hard,compact and covered with smooth and thick catile.This is beneficial to preventing cold and external damage,but disadvantageous for embryo and endosperm to obtain sufficient water and oxygen.The thick peel hinders the growth of radical and embyo and thus limits the germination of seed.With the treatment by sodium hydroxide,the corneous layer of the seed is abscised uniformly,the selerenchymatous cells in the outer layer are destroyed,the cell space is increased,and even the compact tissues in the middle are loosen,letting the water and oxygen enter the seed easily,thereby the germination rate is improved.更多还原