柑桔杂交的胚胎发育

Development of Cross Embryo in Citrus

以雪柑×福桔、雪柑×芦柑、雪柑×(福桔+芦柑)、雪柑×枳壳、芦柑×柚、柚×枳壳等6个组合为实验材料进行胚胎发育的研究.结果表明,授粉后30d.合子处于单细胞状态;授粉后40d,合子开始分裂;授粉后50d,合子形成球形胚,珠心胚尚未侵入胚囊;授粉后55d,合子胚为球形胚或早心形胚,开始有少数珠心胚侵入胚囊;授粉后60d,合子胚为心形胚,珠心胚已大量侵入胚囊;授粉后80d,合子胚为珠心胚所包围,分不清合子胚与珠心胚.不同授粉组合对合子胚、胚珠及果实发育均有一定影响,主要取决于杂交亲本.与种间杂交相比,属间杂交其合子分裂较迟,合子胚发育较慢,珠心胚侵入时期也较迟.

Six cross combinations of Citrus sinensis×C. tangerina, C. sinensis×C. reticulata, C. sinensis×(C.tangerina+C. reticulata), C. sinensis×Poncirus trifoliate, C. reticulata×C. grandis and C. grandis×Poncirus trifoliate six cross combinations were used as experimental materials for the study of embryo development. It was showed that on the 30th day after pollination the zygote was just a single cell. On the 40th day after pollination, the zygote began to divide. On the 50th day after pollination, the zygotic embryo became globose—shaped, nucellar embryoes hadn't invaded into embryo sac. On the 55th day after pollination, some nucellar embryoes invaded into embryo sac. On the 60th day after pollination, the zygotic embryo became heart-shaped, a number of nucellar embryoes invaded into embryo sac. On the 80th day after pollination, the zygotic embryo was surrounded by nucellar embryoes and it wasn't identified among nucellar embryoes. The cross combinations affected the developments of zygotic embryoes, ovules and fruits, the influence was mainly determined by the crossing parents. As compared with interspecies crossing, the zygote division of intergenus crossing was later, the zygotic embryo developed slowly and the nucellar embryoes invading time was also later.