Floral morphology and pistil fertilization ability of female sterile mutant FS-M1 in Brassica napus L.

摘要

A comparison between female mutant FS-M1 and its wild type Ningyou 10 was carried out on ability of pollen germination on stigma and pollen tube development inside style by means of microscopic histological dissection and their floral morphology.Results showed that the floral morphology of FS-M1 differ in some aspects to that of wild type. Pistil length of FS-M1 was shorter than that of wild type. The 6 stamens of FS-M1 were almost equal to each other in length, while that of wild type composed of 4 longer one and 2 shorter one. There were two extra crescent-like organ developed at the ovary base of FS-M1 with missing nectars.Ovary shape and length of FS-M1 was more flat and shorter respectively than that of wild type. Stigma end of FS-M1 shaped a fork-like looking, was differ obviously from wild type. The numbers of papillae cells of FS-M1 was sparse and its size was larger than that of wild type. Number of pollen grains observed on stigma of FS-M1 was less than that on wild type. The papillae cells of FS-M1 was drying and shriveling gradually in 2-3 days after flowering. There were few germinated pollens observed on surface of stigma of FS-M1 after hand-pollination. But no pollen tube found inside the style. Nevertheless there were pollen tubes existing inside the style of FS-M1, resulting in a normal seed-set when hand-pollination was made after excision of the stigma or part of the style. Results from above indicate that losing function of the papillae cells of FS-M1 resulting from its abnoral development is possibly a key factor causing the female sterility.