| 摘要: |
| [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. |
| 关键词: 嵩草种子 发芽率 解剖结构 萌发机理 |
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| 基金项目:西藏科技厅科技攻关项目（2005011） |
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| Effects of different treatments on structure of seeds vessel and germination percentage of 7 species of Kobresia seeds in Tibet |
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| Abstract: |
| 【Objective】 Morphological characteristics were described of seven kinds of Kobresia (K.royleana，K.macrantha，K.choenoides，K.prattii，K.capillifolia，K.humilis and K.pygmaea)seeds from Tibet and the mechanisms how different treatments promote germination percentage were elucidated．【Method】 Those plant seeds were observed by scanning electron microscope with different treatments combining with germination tests.Those seeds of K.royleana and K.choenoides were observed by scanning electron microscope treated with gibberellin，PEG，sulfuric acid and sodium hydroxide.Those seven kinds of plant seeds were germinated after different treatments above contrast with those untreated．【Result】 Except for the thin cell wall of external seed peels of K.royleana seed with some cracks,the other seeds were covered with thick and pykno peels and their protective tissues were very strong，even the embryo was surrounded by the albumn and located near the carpopodium．The effects of different treatments on seeds peels were different.The results elucidated the GA and PEG almost had no katogene to the peels，and the effect of the Sulphuric Acid was also not that good，and the Caustic soda had the best effects，which improved the germination percentage of the 7 species respectively from 91％，0，76％，69％，14％，21％ and 0 to 96％，90％，93％，96％，74％，63％ and 50％．【Conclusion】 The pykno peels limited the gas exchange and the entering of water，while the thick carpopodiums hindered the growing of the corcles．With the treatment of Caustic soda，the corneous layers of the seeds were abscised uniformly，the sclerenchymatous cells in the outer layer destroyed，the cell spaces also increased and even the compact tissues in the middle rarefacted，enabling water and oxygen to enter the seeds easily and as a result，the germination capacity was improved． |
| Key words: Kobresia seed germination percentage anatomy structure germination mechanism |
