西瓜种子败育的胚胎学观察

Embryological observations on seed abortion in watermelon

西瓜子房产生大量胚珠,但只有部分发育为成熟种子,其余均在发育途中败育,因此用显微技术对西瓜种子败育进行了胚胎学观察.结果表明,开花当天,部分胚珠缺少胚囊,成为无胚囊胚珠,这些胚珠没有花粉管进入;部分含胚囊的胚珠也未有花粉管进入,花后l^2d仍未有花粉管进入.授粉后10d,部分种子无胚,部分含有球形胚,部分含有心形胚,部分含鱼雷形胚.果实成熟时,仍然有部分种子不含胚,部分含球形胚,部分含心形胚,部分含鱼雷胚,约半数含有成熟胚.显然,西瓜种子败育有3种方式:(1)胚珠不产生成熟胚囊;(2)不能实现受精作用;(3)胚在发育中途停止发育.

Watermelon produces a large number of ovules, about half of which develop into mature seeds while the rest abort during development. The abortion was examined by means of microscopy. At the flowering day, some ovules lacking embryo sacs were not visited by pollen tubes, and neither were some containing embryo sacs. Pollen tubes were still absent from some embryo sac-containing ovules one or two days after flowering, which underwent degeneration. In the fruits of 10 d after pollination, some seeds lacked embryos, some contained spherical embryos, some contained heart-shaped embryos, and some contained torpedo-shaped embryos. In mature fruits, some lacked embryos, some contained spherical embryos, some contained heart-shaped embryos, some contained torpedo-shaped embryos, and some contained mature embryos. In conclusion, there were three types of abortion:(a) The ovules did not produce mature embryo sacs,(b) No pollen tubes entered the embryo sac-containing ovules for fertilization,(c) The embryos aborted during seed development.