Morphological and anatomical observation on zygotic embryo development in Sorbus pohuashanesis

In order to learn sexual reproduction process and embryo abortion phenomenon in Sorbus pohuashanesis,morphological and anatomical characters of zygotic embryos under different development processes were observed by using paraffin-cut section method.The results showed that endosperm in S.pohuashanesis was nuclear type,and fertilized zygotes of S.pohuashanesis had a static phases for about 5 days.Development of zygotic embryo in S.pohuashanesis had 5 stages: proembryo,globular embryo,heart-shaped embryo,torpedo-shaped embryo and cotyledonary embryo.Zygote was observed at first on May 21st.Zygote developed into proembryos in 6-9 days(at the begging of June),globular embryos in about 15 days after flowering,and then developed into heart-shaped embryos in 5 days.Torpedo-shaped embryos were observed in about one month after flowering,and then developed into cotyledonary embryos after about 10 days.Zygotic embryos ripened at the middle of July.Serious embryo abortion phenomenon usually appeared at early cotyledonary embryo stages.