摘要
扫描电镜观察表明:成熟田菁(Sesbania cannabina)种子的种孔闭锁,种脐具有种脐沟,沟下有一网状管胞群,具贮水和通气功能;种皮的结构由外向内依次为表层、栅栏层、骨状石细胞层及薄壁细胞层。作者用多种有机溶剂浸泡、不同时间浓硫酸腐蚀和机械损伤等方法有控制地损伤种脐和/或种皮的不同层次结构,发现表层和种脐不耐腐蚀,栅栏层细胞壁厚,排列紧密有序,并具有酚类物质,是控制水分进入种皮的主要屏障。适度浓硫酸腐蚀和机械损伤是克服种子不透性,提高萌发率的有效途径。文章还讨论了影响种子透性的因素,作用机理及栅栏层中“亮线”的实质。
SEM observation shows that,the micropyle in mature seed is closed,hilum possesses hilar groove under which there is reticular tracheidal bar,which function as for water-storage and permeation.From out inwards the seedcoat includes four layers viz cuticle,palisade,osteos- clereid and parenchymatous layer The structure of hilum and/or seedcoat was damaged by treating the seed with various kinds of organic solvents and concentrated sulfuric acid in dif- ferent durations or by mechanical methods,was found that surface layer and hilum were erosion-nonresistant;the palisades had thick cell walls and were orderly arranged,and con- tain phenols.They are the main barrier controlling the entrance of water through seedcoat. Erosion with concentrated sulfuric acid and mechanical damage of seedcoat are effective me- thods for overcoming its impermeability and raising germination capacity of seeds.The factors effecting permeability of seeds and their control mechanism as well as the nature of“light line”of palisades were discussed.
基金
国家"863"基金资助课题
关键词
种皮
结构
田菁
透性
Sesbania cannabina
Structure of seedcoat
permeability