中文摘要：

利用常规研究方法,对甜菜单体附加系M14品系（Beta vulgaris L.,VV＋1C、2n=18＋1）的生殖方式进行细胞学与胚胎学研究.结果表明：（1）甜菜单体附加系M14的4代细胞学检查表明：染色体组分别为VV＋1C、2n=18＋1;VV＋0、2n=18＋0;VV＋2C、2n=18＋2;VVV＋0、2n=27＋0;VVV＋1C、2n=27＋1;VVV＋2C、2n=27＋2等,其中VV＋1C、2n=18＋1的植株传递率平均为96.7%,表现为稳定传递,具有二倍体孢子无融合生殖特性;其余各种分离植株的传递率总计为3.25%,有性生殖发生率较低.（2）胚胎学研究表明,二倍体孢子无融合生殖的胚珠中,珠孔处看不到花粉管,胚囊没有发生受精作用.2个助细胞提前退化,半数卵细胞的极性与正常卵细胞相反;卵与次生核不经受精而自发分裂,卵细胞自发分裂产生无性胚,次生核自发分裂产生核型胚乳,而且次生核自发分裂早于卵细胞分裂;有性生殖胚珠中,珠孔处可见多条花粉管,胚囊里见到精卵融合的图像.表明甜菜单体附加系M14是以二倍体孢子无融合生殖为主要繁殖方式,有性生殖为次要敏殖方式的兼性无融合生殖体.

英文摘要：

The reproductive ways of the monosomic addition line M14 （Beta vulgaris L. ,VV＋ 1C, 2n= 18＋1） of sugarbeet were examined in cytology and embryology by conventional method. The results were as follows：（1） the examination of the four generations of M14 revealed that the genomes of its plants VV＋ 1C （2n=18＋1）,VV＋0 （2n=18＋0）,VV＋2C （2n=18＋2） and VVV＋2C （2n=27＋2）. The plants with VV＋IC （2n=18＋1） had a transmissibility of 96.7% thus appearing genetically stable and possessing the apomixis characteristics of diploid spores,and the other segregated plants had a transmissibility of 3.25% and a low sexual-reproduction rate. （2） Embryological examination showed that pollen tubes were not found at the micropyles of the ovules occuring in the apomixis of the diploid spores and thus the embryo sacs were not fertilized. The two synergids degenerated before schedule and half of the oocytes had an opposite polarity to the normal oocytes,the egg cells and secondary nuclei divided by themselves without fertilization, the egg cells forming asexual embryos and the secondary nuclei producing nuclear endosperm; the secondary nuclei began to divide earlier than the egg cells. In the sexual reproduction,several pollen tubes were found at the microphyles and the combination of the egg cells and sperm cells appeared in the embryo sacs. These indicated that the monosomic addition line M14 was a facultative apomict.