【作者】 孙颖；

【导师】 卓丽环；

【作者基本信息】 东北林业大学 ， 园林植物与观赏园艺， 2004， 硕士

【摘要】 鸢尾属(Iris L．)是单子叶植物鸢尾科中最大的属，也是最进化的属。野生的鸢尾属植物生命力强，抗逆性强，绿色期长，观赏价值高，有大面积推广应用的前景。系统地掌握鸢尾属植物种子生物学特性及其种苗的发育过程，将为其育种、扩繁和园林应用提供理论指导与技术支持，对东北地区的城市绿化建设发挥巨大作用。基于此目的，本论文以东北野生鸢尾属中的6种典型植物为研究对象，从种子形态结构、种子各项生理指标(包括生活力、含水量、吸水性)、种子的休眠与萌发、种苗的发育过程几个方面进行研究。研究结果如下： (1)6种鸢尾属植物的种子外观形态差异很大，肉眼即可进行区分。玉蝉花、黄菖蒲、燕子花的结构使其可以在水面漂浮较长时间，直到有满足种子萌发的环境条件出现。这三个种均为湿生植物：溪荪、北陵种皮较薄，但胚乳较为致密，为中生种类：马蔺种皮厚，胚乳硬实，紧紧包被种胚，具有旱生植物的特征。这也是其发芽困难的主要原因。 (2)6个鸢尾种类的种皮亚显微结构区别显著。其中呈网状纹饰的有玉蝉花、溪荪、北陵、黄菖蒲、燕子花5个种类。马蔺纹饰为蜂窝状。本文认为鸢尾属种皮微形态特征的网脊龙骨状、网眼较浅的是较原始特征，表面有凹点或网脊较宽、网眼较深的是较进化的特征。 (3)成熟野生鸢尾种子绝大多数具有活力，种子发芽的内在潜力很大。玉蝉花、溪荪、北陵、黄菖蒲种子生活力在不同时期变化不明显。2年的室温贮藏对马蔺种子的品质产生显著影响，生活力下降了13％。6种鸢尾属植物的种子均具有一定透水性。马蔺胚乳结构较为致密，对水分的吸收有阻碍。种皮厚而致密，也是致使种子发芽率低的原因之一。 (4)6种植物的种子萌发对温度的适应范围基本上趋于一致，即在15℃条件下和30℃条件下均不利于萌发，大部分种类的萌发最适应范围在20～25℃。30／20℃昼夜变温处理有助于种子发芽。尤其是低温层积处理与昼夜变温激素处理有利于种子发芽，但各种种子适宜的激素种类及浓度不同。马蔺种子经过切除部分胚乳的方法可以得到较高的发芽率。 (5)鸢尾属植物种苗的生长规律是：从种子3月开始发芽至6月期间生长缓慢；7月份时生长速度中等；8～10月期间生长快速，11～12月期间生长极慢。根系生长高峰比苗高生长高峰期推迟一个月。根系生长量与苗高生长量的关系不规则。叶片数目与不定根数目在种苗生长过程中存在显著的正相关性。 (6)溪荪、北陵、黄菖蒲、燕子花种苗的子叶只有基鞘，无舌状鞘。这4种鸢尾属植物属于鸭跖草型。玉蝉花种苗子叶的基鞘和舌状鞘均发达，属于蓝耳草型。马蔺幼苗只有舌状鞘而基鞘完全退化，子叶联结继续伸延和下胚轴完全贴合，形成中胚轴。属于迦通尼型。6个种类中只有舌状鞘的马蔺是最进化。其次是具有舌状鞘和基鞘的玉蝉花以及黄菖蒲和燕子花。而溪荪、北陵则是相对原始的种类。 (7)所测定的莺尾属植物中，马蔺的光补偿点、光饱和点均较高，为典型的喜光阳生植物;溪荪光补偿点较低而光饱和点高，说明其能适应多种光照环境，为较耐阴植物:北陵的光补偿点、光饱和点适中，为中性植物:玉蝉花光补偿点高而光饱和点较低;燕子花的光补偿点、光饱和点均较低，为强耐阴植物。更多还原

【Abstract】 Iris L. is the largest and most evolutional genus in Iridaceae. Both life force and resistance in wild Iris are strong at the same time they keep green for long time. So Wild Iris have favourable foreground to large-scale extending. Finding out seeds biological characters and seedlings growth process of Iris will provide theoretic instruct and technical support for breeding, propagation as well as application in garden. In the thesis, we choose six wild species in northeast of China to study the configuration, physiological characteristic, peculiarity of dormancy and bourgeon as well as seedlings growth process. The results as follows:(1) Morphological difference of six species in Iris is obvious. The seeds can be distinguished by naked eye. The structure of I. ensata, I. pseudacorus and I. laevigata could make them floating on the water for a long time before they could germinate under a fitting condition. I.sanguinea and I. typhifolia have thin seed capsules and compact endosperms. The seed testa of I, lactea is thick and keratose. At the meantime, rigid endosperms enwrap the embryo. This is an important obstacle to germinate.(2) The difference of seed testa ultrastructure is notable. The figures of I. ensata, I. sanguinea, I. typhifolia, I. pseudacorus and I. laevigata are all reticular but the figure of I. lactea is alveolate. The latter is more evolutive than the former.(3) Most of mature seeds of wild Iris have activity. The activities of I. ensata, I. sanguinea, I. typhifolia and I. pseudacorus are steady in two years but the activities of/, lactea reduced by 13%. All the seeds of six plants are dank. The structures of endosperm and seed capsule of I. lactea are compact which is one reason lead to the low germination percent of seeds.(4) The adaptive temperature range of six species at which seed can germinate is rough consistent, i.e., 15C and 30C are not adaptive to germinate and the most adaptive temperature range to most species is from 20 C to 25 C. In addition, the alternative temperature change can redound to the germination of seeds in Iris.(5) Seedlings growth rule of Iris is as followed: Seedlings grow slowly from March (germination) to June. They have moderate vegetal speed during July. From August to October, seedlings growth speed is fast followed by a very slowly growth until december the growth stopped. Growth climax of roots lagged a month compared with the growth climax of seedlings.(6) Cotyledons of I.sanguinea, I. typhifolia, I. pseudacorus and I. laevigata seedlings only had basal but no ligular sheath. All these four species belong to commelina type. Basal and ligular sheath of I. ensata seedlings are all perfectly existed, and they belong to cyanotis type. I. lactea seedlings only remain ligular sheath and basal completely degenerated, and neck extend downward until completely joint with hypocotyl forming mesocotyl, which belong to cartonama type.(7) Among chosen plants species, light compensation point (LCP) and light saturation point(LSP) of I. lactea are higher than the others. So I. lactea is a typical light favor plant. LCP of I sanguinea is lower and LSP is higher which show that I. sanguinea is a shade sustainable plant. LCP and LSP of I. typhifolia both are moderate at light point. LCP is higer but LSP of I. ensata is lower so it can bear part time shade condition. LCP and LSP of I, laevigata are lower and the shade endurance is strong.更多还原