Soft-X-irradiated pollen germinate on a stigma, and their tubes elongate into an embryo sac. Subsequent abortion of embryos after pollination by soft-X-irradiated pollen is still under investigation, but may result from soft-X-ray-induced chromosomal abnormalities in the generative nucleus which prevent normal fertilization from occurring. However, Sari et al. (1994) reported that haploid embryos are obtained through pollination with γ-irradiated pollen, which indicates that embryo formation occurs as a pseudogametic phenomenon. Therefore, it is possible for an ovary growing after pollination with soft-X-irradiated pollen to be promoted by auxin derived from the ovule.