When the free nuclei of the endosperm were 16 or 32,the nucellar embryo initial (s) originated from the nucellar cells near the micropylar end of the embryo sac.

• 当胚乳游离核达到16或32个时，最早的珠心胚原始细胞由靠近胚囊珠孔端的珠心细胞分化形成。