假高粱(Sorghum halepense)颖片生物学特性的研究

Studies on the biological characteristics of glumes of Johnsongrass (Sorghum halepense)

从两个方面对假高粱颖片存在的作用进行了研究。一是将 3年采收的子实分为带有颖片的子实、剥去颖片的子实和剥下的颖片与子实混放在一起 3组进行萌发试验 ,并以GA3 处理。结果表明 ,颖片的存在有利于子实的体眠 ,对子实的萌发具有机械阻力和化学抑制 2种作用 ,作用的强度随子实贮藏时间的长短发生变化。二是对颖片进行电镜扫描观察 ,发现假高粱颖片表面分布有一种特殊结构物 ,由头部和柄部构成 ,柄部嵌在颖片的孔洞中 ,头部顶面观呈哑铃形或 8字型。子实休眠期 ,由于特殊结构物的存在 ,隔绝了子实与外界的气体交换。干燥贮存 1年后 ,由于失水 ,哑铃形头部的边缘向上翘起 ,柄部收缩 ,气体进入颖片与子实之间 ,休眠作用逐渐解除。颖片不仅具有保护子实的作用 ,还具有适应子实萌发的形态结构。颖片这种结构与功能的关系具有重要的生物学意义。

Germination of caryopsis of Johnsongrass and its re lation with glumes were studied. The results indicated that the factors causing lower germination percentage of dormant caryopsis are the presence of chemical inhibitor in glumes and mechanism resistance of glumes. The effect of these two factors have obviou s changes during different period of seeds-keeping. Relation between function an d structure of glumes of Johnsongrass were observed. That there are '8_shaped's tructures distributing on the surface of the glumes were observed by using scann i ng electron microscope. The structures control dormant and germination of caryop sis according to analyze. Glumes are useful structures for caryopsis germination and protecting caryopsis of Johnsongrass.