【作者】 卢立娜；

【导师】 李青丰；

【作者基本信息】 内蒙古农业大学 ， 草业科学， 2010， 博士

【摘要】 华北驼绒藜是优良的牧草和生态建设资源,对干旱和半干旱地区的草场改良和沙漠治理具有重要的作用。有关其生殖生物学特性缺乏系统的研究。本文对其花器官发育、开花物候、花部特性、传粉生物学、种子形成和发育、结实格局进行了研究。主要结论如下:(1)花药壁发育为基本型;绒毡层为腺质型;小孢子母细胞减数分裂为同时型;小孢子四分体多为四面体型,偶见十字交叉型;成熟花粉为2细胞型;蓼型胚囊。除有些花药发育后期绒毡层提早解体,产生空花粉外未见异常现象。空花粉的比率较小,不是胚胎败育及结实率低的主要原因。(2)在内蒙古中部地区开花物候比较稳定,雄花8月初始花,花期18～22d,雌花8月中旬始花,花期15～18d。雌、雄单花开花平均持续时间为4～5d。居群内同一植株雌、雄花花期不遇,减少了同株授粉的比例。雌、雄花序呈现为单峰连续集中开花式样;雌、雄花始花时间与花期长度均呈显著负相关,开花数目与花期长度则为显著正相关。(3)在栽培地呼和浩特地区花粉最高活力为82.54%～94%,花粉平均寿命为6～7d;柱头可授期为柱头露出后6～9d,最佳授粉时间是花后6～7d。花粉和柱头的生殖力均较高,不存在生殖障碍。无无融合生殖现象,其繁育系统以异交为主,近交(自交)亲和。在具有异株授粉优势下,保留同株授粉方式,这对野生退化群落的种群恢复具有一定的积极意义。(4)在内蒙古中部地区8月初开始传粉,传粉期历时18～21d。花粉流通量平均为8542粒/cm3·d,传粉全历程和传粉日进程均具有尖峰态散布的特点,具明显的风媒传粉特征。花粉流通量与风速、温度均呈显著性正相关,与相对湿度呈显著性负相关。具有爆发性传粉现象,是规避恶劣环境的传粉机制。自然状态下传粉效率较高,异株授粉花粉管生长速度较同株授粉快,两种授粉方式花粉萌发率均较高,大部分花粉管也能生长到子房上部。(5)胚胎发生类型为藜型,胚乳发育为核型,有些球形原胚后期不进行子叶的分化,此种异常发育是种子败育的一个原因。原胚时期胚发育所需营养物质主要由胚柄转移的多糖提供;分化胚时期所需营养物质由胚乳提供。胚乳的营养主要来源于珠柄转移的多糖,部分来源于宿存助细胞和珠被细胞积累的多糖。干物质积累在花后36d趋于平稳,此时收获种子可减少落粒损失,对种子质量影响也较小。种子成熟后存在一个月的后熟。收获后35d进行发芽试验,在2h内已有少量种子萌发,14h全部萌发完毕。(6)4龄植株结实率及种子千粒重均高于8龄。结实与花的分化时间及花在花序上的位置有关,早分化的花发育的种子较重;始花期和在冠层下部种子由于花粉量限制结实率较低。自然条件下,花/果转化率较低,且具选择性败育现象。在栽培地呼和浩特地区结实存在资源和花粉限制。通过对植株进行适当的修剪、疏枝等自身的资源调控和施肥处理可以提高结实率和种子千粒重。喷施微量元素肥料种子活力下降的比率显著高于对照,不利于种子的贮藏;施氮、钾肥利于种子的贮藏。更多还原

【Abstract】 Ceratoides arborescehs is a good kind of herbage and ecological conservation resource, and has an important role in improving grassland and treatmenting desertification in arid and semi-arid region. In this research, flower organization development, flowering phenology, pollen and stigma characteristics, pollination biology and seed development were studied. The main results as fellows:(1)The development of anther wall was elementary type. The tapetum belonged to glandular type. The cytokinesis of microspore mother cell was simuteneous, and most of the tetrad was tetrahedral, decussation also observed. Mature pollen grain was 2-cells. The embryo sac was Polygonum type. There was no abnormal phenomenon except empty pollen grains were observed at the stage of haploid nuclear microspore. The ratio of empty pollen was small, and was not main reason for embryo abortion and lower seed set rate.(2)The flowering phenology was stable in the middle of Inner Mongolian. The male flower onset was at the beginning of August, and flowering duration was 18～22d, and female was in the middle of August, duration was 15～18d. Flowering duration of single male and female flower was 4～5d. Both female and male inflorescence were single peak of curve. There is a significant negative correlation between the date of first flowering and duration of female and male inflorescence, and a significant active correlation between flowering numbers and duration. During long term evolution of Ceratoides arborescens had an adaptive stratege of female and male flowering time was not encounter, which reduce proportion of geitonogamy and improve seed set rate.(3)The highest pollen viability was 82.54%～94% in Hohhot, average pollen life was 6～7d, receptivity of stigma was 6～9d after stigma sprouted, the best pollination time was 6～7d after flowering, which had the biggest seed set rate. Reproductive ability of pollen and stigma was stronger, and had no reproductive barrier. Ceratoides arborescehs had no apomixe, the breeding system is mixed with self-compatible and outcrossing. In order to avoid geitonogamy, it took dichogamous and sexual dimorphism. In the advantage of having xenogamous, it took geitonogam simultaneous, which is significant for wild population restoration.(4)Pollination began at the beginning of August in the middle of Inner Mongolia. Pollination duration was 18～21d. Average pollen density was 8542 grain/m3·d, had obvious characteristics of anemophilous. It has a sharp single apex in pollination period. Pollen density had a significant active correlation with wind speed and temperature, a significant negative correlation with relative humidity. Pollination was explosive, which can avoid bad environment.The pollination efficiency was high. The experiment of pollen germination and pollen tube growth showed: the pollen tube of xenogamous grew faster than geitonogamy. Both pollen germination rate was higher, and most pollen tube can grow to upper of ovary.(5)The embryo development was Chenopodiad type. The style of endosperm development was nuclear type. We observed abnormal development phenomenon in later globular embryo, they did not undergo normal divisions, which was one of the reason of embryo abortion. The nutrient transportation was associated with the persistent synergid. The nutrient that needed for embryo development had been supplied mainly by endosberm since the embryo differentiation period. The nutrient of endosperm mainly came from amylase of funicle, and partly come from synergids. Moisture of seed was 39.89% after 40d since flowering, and was stability. Nutritent accumulation tended to stabilize after 36d since flowering, It was suitable for harvest after 36d since flowering, because it can decrease loss. It had 30d dormancy after seed maturation. Germination after 35d since harvest showed: There were a few of seeds germinate in 2h of 3 years old plant, The whole seeds germination completed in 14h.(6)The seed set rate and 1000 seeds weight of 4 years old plant were higher than 8 years old plant. Seed set rate was related to the time of flower differentiation and the floret sites. Flowering earlier produced larger seeds than those flowering later, and basal flower produced larger seeds than the middle and distal. Flower of early flowering and lower layer produced lower seed set rate by the reason of pollen restriction. The flower-fruit transformation was lower, and existed selective abortion. Seed set existed resource and pollen restriction in cultivated population. The seed set rate and 1000 seed weight obviously increased through advisable trimming branches, decreasing the density and supplied fertilizer, which can control plant theirself resource and suppling resource. It was unsuitable to spray micro-fertilizer for seed storage, supply Nitrogen and Potassium feitilizer was suitable for seed storage.更多还原