西瓜雄性不育类型的遗传学鉴定与胚胎学观察

Genetic identification and embryological observation of male sterile watermelon

为了明确西瓜雄性不育材料的不育类型和花药败育时期,以西瓜雄性不育系GMS4为材料,对花蕾不育性状进行田间观察统计,利用石蜡切片法观察西瓜花药发育过程。结果表明,该材料不育性状由1对隐性基因控制,为细胞核雄性不育类型。可育株雄蕊发育正常,不育株雄蕊较小,花药干瘪无花粉,可育株和不育株雌蕊发育无明显差异,均可正常结瓜。从花药发育的整个过程来看,在花药发育早期,可育株和不育株花药结构形态差别不大,在小孢子母细胞减数分裂期,不育株异常绒毡层细胞过度增殖,体积小,排列不整齐,挤压药室,无二分体和四分体形成,在花药发育后期,无花粉粒形成,最终导致西瓜雄性不育发生。据此认为,花药败育发生时期在小孢子母细胞减数分裂期。

In order to determine the sterility type and anther sterilization period of male sterile watermelon,the male sterile line GMS4 was used as the material to observe the sterility characters of flower buds in the field,and the development process of watermelon anther was observed by the paraffin section method.The results showed that the sterile material was controlled by a pair of recessive genes,which was the type of nuclear male sterility.The stamen of fertile plant was normal while that of sterile plant was small,with shripped auther and no pollen.There was no difference in pistil development between fertile strain and sterile plant,and both of them could bear fruit normally.In the early anther development,there was little difference in anther structure and morphology between fertile and sterile plants.In the meiotic phase of microspore mother cells,the abnormal tapetum cells proliferate excessively,were small in size,irregular in arrangement,squeezed drug chamber,and no dyad and tetrad were formed.No pollen grains were formed at the late anther development stage,which resulted in male sterility.It concluded that anther abortion occurred during the meiosis stage of microspore mother cells.