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【目的】观察了西藏7种嵩草(喜马拉雅嵩草、大花嵩草、藏北嵩草、短轴嵩草、线叶嵩草、矮生嵩草、高山嵩草)种子的形态特征,阐明不同种子预处理方法提高其发芽率的机理。【方法】对采自西藏的7种嵩草种子形态特征进行了扫描电镜观察,并对其中的喜马拉雅嵩草和藏北嵩草种子进行了赤霉素、PEG、H2SO4、NaOH处理后的扫描电镜观察;以未预处理种子为对照,对7种处理后的嵩草种子进行了萌发试验。【结果】除喜马拉雅嵩草种子果皮最外层表皮细胞的细胞壁较薄且有裂孔外,其他几种嵩草种子都具有果皮厚、外表致密、保护组织机械性强、胚位于胚乳之中果柄一侧等特征。不同预处理方式对果皮的影响不同,赤霉素、PEG对果皮几乎无机械破坏作用;硫酸对果皮有一定的破坏作用,但作用较为有限;氢氧化钠对果皮的机械破坏效果最好,使上述7种种子的发芽率依次由未经任何预处理的91%,0,76%,69%,14%,21%和0,分别提高到96%,90%,93%,96%,74%,63%和50%。【结论】嵩草属种子致密的果皮,限制了其气体的交换和水分的进入,过厚的果柄也限制了胚根和胚芽的穿破能力;NaOH处理种子能均匀去掉果皮角质层,甚至破坏果皮最外层的大型厚壁细胞,增大细胞间隙,使中间的纵向致密组织变得疏松,有利于水分和氧气进入种子,从而提高了发芽率。
【Objective】 Morphological characteristics of seeds of seven Kobresia species in Kobresia (Himalayas, Kobresia, Kobresia, Kobresia, Kobresia, Kobresia, Kobersia kobiensis) in Tibet were observed, The mechanism of different seed pretreatment methods to improve their germination rate. 【Method】 Morphological characteristics of seven species of Kobresia humilis collected from Tibet were observed by scanning electron microscope (SEM), and the seeds of Himalaya kobresia and Kobresia pygmaea were treated with GA, PEG, H2SO4 and NaOH The seed germination test of seven Kobresia species was carried out with the non-pretreated seeds as control. 【Result】 Except for the thin and cracked cell wall of the outermost epidermal cells in the pericarp of Kobresia humilis, the other Kobresia species had thick pericarp, dense appearance and strong mechanical protection, and the embryo was located in the endosperm of the endosperm One side and other features. Different pretreatment methods have different effects on pericarp. Gibberellin and PEG have almost no mechanical damage on the pericarp. Sulfuric acid has a certain destructive effect on pericarp, but the effect is limited. Sodium hydroxide has the best mechanical destruction effect on the pericarp. The germination rate of the above seven kinds of seeds increased from 91%, 0,76%, 69%, 14%, 21% and 0 without any pretreatment to 96%, 90%, 93%, 96%, 74 %, 63% and 50%. 【Conclusion】 The seeds of Kobresia seed had a dense peel, which restricted the exchange of gas and the entry of water. Too thick stems also limited the ability of radicle and embryo to penetrate. NaOH treatment of seeds could remove the stratum corneum even, and even Destroy the outermost pericarp of large-scale thick-walled cells, increasing the cell gap, so that the middle of the longitudinal dense tissue becomes loose, is conducive to moisture and oxygen into the seeds, thereby increasing the germination rate.