摘要 |
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Abstract | In order to understand the development processes of reproductive organs of Nymphaea tetragona Georgi, the changes of anatomical structure of microspore and male gametophyte transverse sections and megaspore, female gametophyte and ovary longitudinal sections were observed by using the technology of paraffin section, and the pollen characteristics, pollen germination rate, and self-seeds setting rate were studied by using technologies such as in vitro culture and artificial pollination. The results show that the male gametophyte of N. tetragona develops into mature anther through a series of processes, namely pollen mother cell stage, meiosis stage, tetrad stage, microspore free stage, mononuclear sideline stage, mononuclear pollen stage, and binuclear pollen stage; the anther contains four pollen sacs, and the anther wall is composed of one layer of epidermal cells, one layer of anther chamber wall cells, two layers of middle layer cells, and one layer of secretory tapetum cells from outside to inside; the shape of mature pollen grain is spherical to ellipsoid, and the pollen groove is a ring germination groove; the germination rate of pollen in vitro is 45.2%. The female gametophyte of N. tetragona develops into a complete embryo sac through a series of processes, namely megaspore mother cell stage, dyad stage, tetrad stage, mononuclear embryo sac stage, binuclear embryo sac stage, and tetranuclear embryo sac stage; and the megaspore near the chalazal region of megaspore tetrad is functional megaspore; the mature embryo sac is a four-cell/four-nuclear embryo sac, which is composed of one mononuclear central cell, one egg cell, and two synergids; the ovule is double integuments, thick nucellus and marginal placentation. The embryonic development of N. tetragona goes through three stages, namely globular embryo, ellipsoidal embryo, and rhombic embryo, and its endosperm is cellular endosperm. In addition, some developmental abnormalities can occur in the development processes of reproductive organs of N. tetragona, in which, there are phenomena such as early disintegration of tapetum cells and irregular shape of tetrad during the development of male gametophyte, resulting in abnormal pollen development; and there are megaspore stagnation and abnormal nuclear disintegration in embryo sac during the development of female gametophyte; in the ovary after aritificial pollination, there are abnormal phenomena such as embryo stop development, structural disorder, and nuclear disintegration, resulting in embryo abortion. It is suggested that the functional megaspores of N. tetragona located at the chalazal region and four-cell/four-nuclear mature embryo sacs are important reproductive characteristics different from most angiosperms; the abortions during megaspore, microspore, male and female gametophyte, and embryo development may reduce the crossselfseeds setting rate of N. tetragona.
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关键词 | 睡莲; 生殖器官; 解剖结构; 雌配子体; 雄配子体; 胚胎发育 |
Key words | Nymphaea tetragona Georgi; reproductive organ; anatomical structure; female gametophyte; male gametophyte; embryo development |
作者 | 孙春青1,2, 陶美奇1, 姚悦梅1, 戴忠良1 |
所在单位 | 1. 江苏丘陵地区镇江农业科学研究所, 江苏 句容 212400; 2. 南京农业大学园艺学院, 江苏 南京 210095 |
点击量 | 1789 |
下载次数 | 984 |
基金项目 | 国家自然科学基金资助项目(31701948); 镇江市重点研发计划项目(NY2021016) |