【作者】 宛涛；

【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， 2011， 博士

【摘要】 本项研究以分布在内蒙古典型草原和荒漠草原上的优良牧草冷蒿为供试材料,针对其雌雄配子的发育、染色体核型特点、花粉形态特征传粉规律及种子萌发特点等问题进行探讨。研究成果认为:1.冷蒿小孢子的发生为多胞原;花粉母细胞胞质的分裂属于连续型;绒毡层属于变形绒毡层;成熟的雄配子为2核型。2.冷蒿的胚胎发育属于单孢型胚囊,四分体直线型排列,其功能大孢子存在于合点端。3.在内蒙古冷蒿既有二倍体又有四倍体;二倍体染色体数目为2n=2x=18;四倍体染色体数目为2n=4x=36。唯有来自于塔尔岭的材料具有随体;在冷蒿的正种(Artemisia frigida Willd.)及变种—紫花冷蒿(Artemisia frigida Willd. var. atropurpurea Pamp.)中都存在二倍体和四倍体的现象。4.冷蒿的花粉粒属于小型花粉粒。赤道面为椭圆形或圆球形;极面为三裂圆形或三裂片圆形。萌发器官是3孔沟类型;花粉粒表面纹饰为刺状—颗粒状复合纹饰。冷蒿正种的花粉粒为椭圆形或长球形,而变种的花粉粒为圆球形或近圆球形。来自鄂托克的材料(变种,四倍体)二型性比例最高,可达64.5%,P/E=1.07;其他样点的材料二型性比例不足20%。5.花序开花顺序初期是由上至下的,对于每一花序开花顺序为,外轮的单性小花先开放,2-4天后中央两性小花开始开放。冷蒿花粉在水平方向上随着距离的增加,所传播的花粉粒数量越少,大多遗留在植株附近,其传播的有效距离大于200cm;在垂直方向上距地面越高收集到的花粉数量越少,其传播的有效高度大于100cm;在1昼夜内,09:00时左右和13:00时左右,各出现1次十分明显的花粉捕获高峰期。温度、风速与花粉密度呈正相关,而相对湿度与花粉密度存在负相关。6.冷蒿瘦果背面为条纹状纹饰,由于分类地位、染色体倍性、生境的不同,条纹状纹饰的形态、排列及一些瘤状物、突起物等辅纹饰有所差异。7.来自8个样地冷蒿种子千粒重的变化幅度在0.076g-0.124g之间;克什克腾冷蒿种子的萌发率(GR)、萌发势(GE)、萌发指数(GI)和活力指数(VI)均最高,与其他7个样地的种子萌发特性相比差异达到0.05。在含水量达到30%以后发芽率开始下降。种子在土壤表层萌发率最高;覆土厚度超过3 cm以上时不能出苗。更多还原

【Abstract】 Development of female gamete and male gamete, karyotype, pollen morphologcial characterisrtics,pollination law and seed germination characters of Artemisia frigida , as a good forage,was dstributed in typical steppe and dertsteppe in Inner Mongolia.The results showed: (1)The generation of microspore of Artemisia frigida is from poly archesporial cells; division of cytoplasm of pollen mother cell was consecutive type; tapetum was deformed tapetum; mature androgamete was two cell type. (2)Embryo development of Artemisia frigida was embryo sac of polygonum type.Tetrad arranged in a line, functional macrospore was in end of chalaza. (3)There were both diploid and tetraploid of Artemisia frigida , including Artemisia frigida Willd.and Artemisia frigida Willd. var. atropurpurea Pamp; the chromosome number of diploid was 2n=2x=18; tetraploid was 2n=4x=36. Only accession from Taerlin had satellite. (4)All the pollens were small pollen. Equatorial plane was oval or round; pole plane was three breached round. Germination organ was three hole or ditch type; sculpture on surface was compound sculpture of thorn and grain. The pollen of Artemisia frigida Willd. was oval or long spherical and Artemisia frigida Willd. var. atropurpurea Pamp.was spherical or near spherical. The dimorphism ratio in accessions (varietas, tetralpoid)from Etuoke was the highest, reached 64.5%,P/E=1.07; others was lower than 20%.(5)Flowers in inflorescence bloomed from up to down at initial stage. Outer florets bloomed first, middle florets bloomed 2-4 days latter. In horizontal direction, with the increase of distance, the quantity of pollen speed was less and less, most of pollens remained near plants, the effective spread distance was more than 200 cm. In vertical direction ,the higher, the less the pollens collected, the effective spread height was more than 100 cm .Peak time captured pollens appeared at 9:00 and 13:00 in one day and one night .Temperature and wind speed were positively correlated to pollen density; relative humidity was negatively correlated to pollen density.(6) There were striped sculptures on back of achene of Artemisia frigida and differences in morphology , arrangement , tumour and protuberance of striped sculptures due to the differences of taxonomy position, chromosome ploidy and habitants.(7)1000-seed weights of Artemisia frigida from eight sampling sites were 0.076g-0.124g .Germination rate, germination energy, germination index and vigor index of seeds of Artemisia frigida from Keshiketeng were all the highest, there were differences in seed germination characters compared with others (P<0.05). Seed germination rate began to decline when the moisture content was more than 30% and on the surface of soil was the highest .when the thickness covered with soil was more than 3cm, the seeds can not germinate.更多还原