Abstract:In a mature embryo sac of wheat (Triticum aestivum) the egg contained numerous perinuclear starch grains and fewer diffused lipid globules. The synergids contained a lot of lipids but no starch grains whereas the central cells contained only a moderate amount of diffused starch grains and lipids. There was little change of starch grain contents in all cells of an embryo sac during fertilization. The lipid globules increased sharply in the egg and central cells at the time of fusion of sperm and egg nuclei. Zygote and the corresponding free nuclear endosperm contained fewer diffused lipid globules. At early proembryo stage the proembryo cells and endosperm contained numerous lipid globules in their cytoplasm. The lipid content exhibited a regular change in the inner integument cells of an ovule. No cytoplasmic storage protein was detected in ovules at all observed stages. The changes of lipids in ovules might be associated with the nutrient of the female cells and early proembryo, and the chemotropic growth of pollen tubes.