摘要
在以 6份同源四倍体水稻为杂交母本与狼尾草进行属间杂交中发现 ,其结实率达到 0 .84%～ 2 .0 6% ,而在以二倍体水稻为母本的属间杂交中却没有获得结实种子。利用激光扫描共聚焦显微技术对属间杂交结籽的特殊生殖现象进行了观察研究 ,试图寻找其杂交结实的胚胎学证据。结果表明 ,狼尾草的花粉粒不能在二倍体水稻的柱头上萌发 ,说明二倍体水稻与狼尾草的生殖隔离很严格 ,两者很难杂交。然而 ,狼尾草的花粉粒在同源四倍体水稻的柱头上能萌发 ,花粉管能在花柱中伸长并能将雄配子送入胚囊内与雌配子融合成受精卵。同源四倍体水稻与狼尾草的受精作用比较特殊 ,包括精细胞与卵细胞的单受精作用、精细胞与次生极核的单受精作用和正常的双受精作用 ,总受精率和总成胚率分别为 6.3 6%～ 11.68%和 4.11%～ 9.44 %。试验结果为解释同源四倍体水稻与狼尾草杂交结籽的特殊生殖现象提供了有力的胚胎学证据。
It was found that the seed-setting rates of the Intergeneric crosses between 6 autotetraploid rices (as the female) andPennisetum alopecuroides (as the male) were as high as 0.84%～2.06%, but no seeds were obtained in the intergeneric crosses between the 6 corresponding diploid rices and P.alopecuroides. To search for the embryological evidences, the special reproductive phenomenon of seed-setting in intergeneric hybridization was surveyed by the Laser Scanning Confocal Microscopy (LSCM). The results showed that the active pollens fromP.alopecuroides did not germinate on the stigmas of diploid rice at all, indicating that there is a very strict reproductive isolation between diploid rice andP.alopecaroides. However, the active pollens of P.alopecuroides could not only geminate on the stigmas of autotetraploid rice, but the pollen tubes could extend in the style, penetrate into the embryo sac at the micropyle end and get fertilized with female gamets. The fertilization in the hybridization was rather peculiar and included the single-fertilization of a sperm with an egg, the single-fertilization of a sperm with a secondary polar nucleus and the normal double-fertilization. The total fertilization rate and total embryo formation rate in the intergeneric crosses of autotetraploid rice andP.alopecuroides were 6.36%～11.68% and 4.11%～9.44%, respectively. The above experimental results provide a good embryological evidence for the special reproductive phenomenon of seed-setting in the distant hybridization between autotetraploid rice andP.alopecuroides.
出处
《杂交水稻》
CSCD
北大核心
2004年第1期56-59,共4页
Hybrid Rice
基金
湖南省自然科学基金资助项目 (0 0JJY2 0 72 )
关键词
同源四倍体水稻
狼尾草
远缘杂交
结实
胚胎学证据
tetraploid rice
Pennisetum alopecuoides
distant hybridization
seed-setting
embryological evidence
