【作者】 王育青；

【导师】 孙启忠；

【作者基本信息】 中国农业科学院 ， 草地资源利用与保护， 2010， 博士

【摘要】 采用野外定位试验观测与室内实验相结合的试验方案,从生物学、生理学、细胞学、胚胎学、遗传学等方面,围绕马蔺各阶段不同繁殖特性展开研究,为马蔺种子生产、应用及其种质资源研究和开发提供科学依据。针对不同生态区马蔺,从种子萌发与休眠解除技术,开花生物学特性,传粉生物学特性,繁育系统研究,农艺性状分析和ISSR遗传分析等六方面对其进行了研究,进而揭示马蔺开花、传粉、繁殖等生理生化动态变化,探讨马蔺种子休眠原因,寻找打破马蔺种子休眠技术和确定适宜种子萌发的条件,同时明确不同种群材料的亲缘关系。主要研究结果如下:1.马蔺种子生活力较高,胚发育不完全,具有形态后熟特性。种子自然萌发率较低,种皮较厚、革质、占种子总重量的31.7%,种子特性对吸水无明显阻碍,对萌发有机械阻力,也是马蔺种子休眠的主要原因之一;种皮和胚乳浸提液中均不存在发芽抑制物,马蔺种子休眠为自发性综合休眠;在生产上,采用层积和40%NaOH处理8h等方法,可以提高种子发芽率。2.生长多年的马蔺花朵数可达15～55朵,总体花期长达35d以上;马蔺始花日期、开花高峰日期、终花期、开花持续期在年度间无明显差异,且个体在年度间能够保持相近的开花物候进程(开花振幅曲线)。马蔺花的开放主要受温度、光照、湿度等气候因子影响,马蔺开花数和座果数均与开花时间呈负相性,开花数与座果数呈极显著正相关。3. 9:00～10:00马蔺花朵开放散粉后,其花粉生活力最强,之后逐渐降低,到下午18:30花粉活力已降到9.58%,花粉的贮藏环境与花粉生活力密切相关;马蔺具有自交不亲和性,以昆虫为传粉媒介,是异花授粉植物,授粉中可以去垂瓣作为其有效隔离机制。4.马蔺依靠花粉萌发形成花粉管传递,进入胚囊释放内溶物,融合,进而完成双受精;胚乳发育类型为核型,从开花到种子成熟需要60d左右,马蔺每枝花序上具1～4果,蒴果先端具喙,成熟的果实尖端3裂,平均每蒴果内含种子为50粒,马蔺种子的产量和产草量取决于分蘖芽的数量。5.马蔺种群农艺性状表现出不同程度的变异性。千粒重、发芽率、吸水率、胚长、胚乳长、种子长、生殖枝、营养枝、叶宽、株高等10个主要性状是引起不同来源种群分化的主要因素。胚长、千粒重、吸水率等易受环境因子影响。聚类结果显示,绝大多数种群材料表现出明显的地域性。经、纬度相近的种群聚类在一起。6.马蔺表现出丰富的遗传多样性。不同种源马蔺多态性带数比例为91.1%。UPGMA聚类将20个种群分为4大类群。种群间亲缘关系与纬度相关性显著,与其所处生境存在一定的相关性,与农艺性状研究结果吻合,建立并优化了马蔺ISSR-PCR扩增反应体系。更多还原

【Abstract】 Combined with both field observation and laboratory test methods, the propagation characters of Iris lactea, were studied based on the experiments from different levels such as biology, physiology, cytology, embryology and genetics. The framework of this dissertation is the propagation cycle of Iris lactea, which begins from seeds germination and end in the formation of new seeds. The main contents including: to develop new knowledge of the mechanism of seed dormancy and new techniques to breaking seed dormancy, features of Iris lactea on flowering biology and pollination biology, breeding system of Iris lactea, genetic variation analysis of its agronomic traits and ISSR marker in different ecological regions and so on. The dynamic changes of chemical and physiological process during seed germination, florescence, pollen, fertilization were observed and analyzed; In-depth research on the Iris lactea mechanism in terms of its seed dormancy were going to find dormancy breaking technology and determine appropriate germinating conditions; The genetic diversity and relationship among populations of Iris lactea were studied, from the level of agronomic traits and DNA molecular, which come from 20 different regions in Inner Mongolia. The results of the above tests completed will establish developing system theory basis for Iris lactea .The main conclusion were as follows:1. Due to immature embryo, the fresh seeds of Iris lactea were in the state of after-ripening with low germination ability under wild conditions. One of the key reasons of seed dormancy was the thick seed coat, which covered 31.7% of total seed weight and inhibits the growth of embryo during seed germination. Moreover, no inhabitation chemicals of soaking liquid of seed coat and albumen which meaned that the seed dormancy of Iris lactea was spontaneous. Stratification and soaking for 8 hours in 40% NAOH were effective methods to improve the germination of Iris lactea seeds.2. There were 15 to 55 flowers per plants with 35 days of florescence. There was no significance difference of data to the initiation, peak and ending of florescence between different years. The florescence was mainly affected by such factors as temperature, light and humidity. Moreover, the number of flowers and seeds was negative related to the date of flowering. The number of flowers had positive relation with the number of seeds.3. The vigor of pollen was highest on the 9:00～10:00 a.m during the day. After that, the vigor of pollen began falling which falled to 9.85% at 6:30 p.m. The storing environment had great effect on the vigor of pollen. The Iris lactea was the plant of self incompatibity, which was pollen by insects. The elimination of valve was one of effective isolation pathways.4. The double fertilization of Iris lactea was achieved through the special channel provided by the pollen tube. The type of endosperm development belongs to nucleolus type. It required about 60 days from florescence to seed ripeness. There were 1~4 seeds per anthotaxy. Capsule had a beak on its top, with 3 splits pre capsule. There were 50 seeds per capsule. The production of seed and biomass was determined by the number of tiller buds.5. Agronomic traits of Iris lactea populations showed abundant variation. There were 10 main characters that caused variation among populations from different sources, including grain weight, germination rate, water absorption, the embryo length, endosperm length, seed length, fertile tillers, vegetative shoot, leaf width, plant height. Embryo length, grain weight, water absorption are affected easily by environmental factors. Clustering results showed that the majority of population materials showed significant regional sources. If longitude and latitude of population materials were similar, then they clustered together.6. Genetic diversity of Iris lactea showed rich. The percentage of polymorphic bands was 91.1% from different sources. 20 populations were divided into four major groups by UPGMA clustering. Genetic relationship among populations was significantly correlated with its latitude, and there was a certain correlation with their habitats. The above ISSR research results agreed with the above agronomic research. Furthermore, ISSR-PCR amplification reaction systems of Iris lactea established.更多还原