EN
Zygotes fertilized in planta developed into fertile plants in vitro. Microspore cultures and ovaries derived from the same species were tested as nurse cells. With both types of feeder system about 20% of the isolated zygotes were able to regenerate into plants. The morphology, cytological properties and development rhythm of the zygotes resembled those of the in vivo course of zygotic development, except that the first division appeared symmetrical in contrast to the asymmetrical division observable in planta. The results indicate that ovaries may have the same nurse effect as microspores on zygotes cultured in vitro. Using ovaries as a nurse system is much less time-consuming than using isolated microspore cultures.