丽椪2号椪柑无核机制研究

Studies on the seedless mechanism of Lipeng No.2 Ponkan(Citrus reticulata)

为系统探明椪柑无核发生的机制,以无核椪柑新品种丽椪2号和普通有核椪柑为试材,对雌雄配子体的育性和亲和性进行了观察。结果表明,丽椪2号花粉发芽率、花粉染色活力和花粉粒数量等与有核对照存在显著性差异,属于低育型花粉。丽椪2号花粉母细胞在减数分裂期染色体行为发生了异常,出现较高频率的染色体链及少部分的染色体环和落后染色体。授以高育性的雪柑花粉后,丽椪2号仍能形成无核果。切片观察发现,丽椪2号胚囊母细胞在四核期已完全退化。因此,胚囊高度败育是丽椪2号产生无核的主要原因。

In order to explore the seedless mechanism of Ponkan（Citrus reticulata Blanco）, new seedless Ponkan cultivar Lipeng No. 2 and common seedy Ponkan cultivar were used as materials for observing fertility and compatibility of male and female gametophyte. Results showed that pollen germination rate, pollen stain-ability, pollen grain amount and so on had remarkable difference between the two cuhivars and Lipeng No. 2 pollen belonged to low-fertility type. Partial chromosomes happened abnormally during pollen mother cells meiosis, which included chromosome chain, chromosome loop, lagging chromosome and chromosome unequal distribution. Lipeng No. 2 produced seedless fruit all the same when pollinated with Xuegan orange cultivar. Observation by paraffin section showed that Lipeng No. 2 embryo sac mother cells were almost entirely degenerated during megasporogenesis. It is concluded that embryo sac sterility was the main reason for highly stable seedless characteristic of Lipeng No. 2 cultivar.