二月兰个体发育早期特性研究

Study on the Characteristics of Early ontogeny of Orychophragmus violaceus

以二月兰为试材,借助石蜡切片和电镜扫描技术,研究了其种子形态和器官早期阶段的发育特点。结果表明:二月兰种子为圆柱形,表面粗糙,有凸起的纵条纹状纹饰。种子离开母体时胚已经完全分化,子叶纵折型。种子萌发时下胚轴与胚根交界处出现根环和根环毛,根环毛出现的时间和位置与根毛不同,两者结构相似。种苗子叶期至少7d以上,明显表现为种苗根端先发育,苗端后发育。二月兰个体发育早期出现水生性状,后期发育出现陆生性状。

The seed morphology and characteristics of organ development at early stage of Orychophragmus violaceus were studied by means of paraffin section and scanning electron microscopy. The results showed that the seeds of O.violaceus were cylindrical,with rough surface and prominent longitudinal stripes. The embryo was fully differentiated and the cotyledon was longitudinally folded when the seed left the mother. During germination of seeds,collet and collet hairs appeared at the junction of hypocotyl and radicle. The appearance time and location of collet hairs were different from the root hairs,but they were similar in structure. The cotyledon stage of seedlings was at least one week,and it was evident that the priority of development was root end,later at the shoot end. To sum up,in early stage of ontogeny of O. violaceus showed aquatic characters,and in the later stage,terrestrial traits appeared.