无核红江橙的无核成因探讨

Study on the seedless mechanism of seedless ‘Hongjiangcheng'

以无核红江橙和普通有核红江橙为试验材料,对其花粉育性、成熟胚囊结构以及胚胎发育进行了研究。结果表明:(1)无核红江橙花粉出现败育的现象,花粉的生活力和发芽率显著降低,花粉的畸形率显著升高,花粉育性属于低育型。(2)无核红江橙胚囊发育是正常的,具有1个卵细胞、2个助细胞、3个反足细胞和1个中央细胞。(3)无核红江橙胚胎发育也出现败育的现象,授粉后4周胚体开始退化,授粉后6周胚乳出现退化,授粉后7周胚胎完全退化消失,最终形成无核果实。综合分析,花粉败育和胚胎败育是无核红江橙无核的主要原因。

The seedless ‘Hongjiangcheng＇〔Citrus sinensis（L.） Osbeck〕and seedy ‘Hongjiangcheng＇ were used as materials of the experiment in the study.Their pollen viability and germinating viability,embryo sac fertility and embryonic development were studied.The results showed that,compared with the seedy ‘Hongjiangcheng＇,the pollen sterility of seedless ‘Hongjiangcheng＇ happened,the pollen viability and germinating viability significantly declined and rate of malformation significantly rised at the same time.The pollen viability and germinating viability of seedless ‘Hongjiangcheng＇ belonged to the type of low development.The embryo sac of seedless ‘Hongjiangcheng＇ could fertilize normally.Mature embryo sac had one egg,two synergids,three antipodal cells and a big central cell which contained two polar nuclei.The embryonic development of seedless ‘Hongjiangcheng＇ happened according to the study of a few different periods.The most embryos began to degenerate at the four weeks after pollination.The endosperms disappeared with development and maturity of cells in the six weeks after pollination.And in the seven weeks after pollination,the most embryos and endosperms disappeared and seedless fruits produced in the end.The degeneration of pollen and embryos was the mainly seedless reason for seedless ‘Hongjiangcheng＇development compared with seedy ‘Hongjiangcheng＇.