【摘要】 以薄皮和厚皮类型甜瓜为试材,采用改良的染色体制片方法,系统观察了甜瓜花粉母细胞的减数分裂及雄配子体发育的过程,结果表明:(1)甜瓜细胞核减数分裂的同步性较高,细胞质是同时型分裂,在细胞核分裂的过程中,核仁在前期Ⅰ到中期Ⅰ逐渐消失,在前期Ⅱ再次出现,随后消失,染色体在前期Ⅰ到中期Ⅰ逐渐收缩,变得清晰,至末期Ⅰ变得模糊,在前期Ⅱ再次清晰;(2)2种类型甜瓜终变期的染色体构型都以环状二价体为主;(3)在后期Ⅱ,观察到染色体的垂直和平行2种分离方式;(4)在前期Ⅰ和前期Ⅱ,伽师瓜"形成了多个较小的核仁,呈现一定的特殊性;(5)雄配子体发育经历了单核期和双核期,最后形成了成熟的花粉粒.研究表明,薄皮和厚皮类型甜瓜减数分裂的染色体行为基本一致,没有明显差异;伽师瓜"的核仁数量表现特殊可能与其长期的生态适应性有关.更多还原

【Abstract】 With improved staining and chromosome preparing method,thin and thick rind melon(Cucumis melo L.) were used to study meiosis of pollen mother cells(PMC) and development of male gametophyte.The results indicated:(1)both types of melon have a simultaneous cytokinesis and a relative high synchronization in nuclear division.Nucleolus disappeared gradually from prophase Ⅰ to metaphase Ⅰ,reappeared at prophaseⅡand then disappeared.With condensation of chromatins,chromosome became more and more identifiable from prophase Ⅰ to metaphase Ⅰ,and illegible at telophase Ⅰ with de-helixation.Chromosomes were prominent again at both poles in PMC at prophase Ⅱ.(2)At diakinesis,most chromosome configurations were ring bivalents for all melons.(3)Two kinds division of chromosome were observed at anaphase Ⅱ,reciprocally vertical and parallel division.(4)Nucleolus number was more than other melons both at prophase Ⅰ and Ⅱ in Jiashi melon,which demonstrating the speciality of Jiashi melon.(5)During the development of male gametophyte,unicleate,bicleate and mature 3-celled pollen stage were observed in both types melon.It could be concluded that meiotic chromosome behaviors of PMC was accordant between two types melon in China,and the unique nucleolus number shown in Jiashi melon was relevant to ecological adaptability.更多还原