It is generally from a few hours to one to two days. During pollen tube growth in Lilium the generative cell divides once by mitosis to produce two sperm cells. The mature microgametophyte consists of the tube cell nucleus and two sperm. The ovule primordium is a small dome-shaped swelling that arises from the inner wall of the ovary. A micropyle is present at one end of the ovule.
Thin walls develop around six of the nuclei.
At the micropyle end of the megagametophyte an egg cell is flanked by two synergids . At the opposite end of the megagametophyte are three antipodals . The large central region of the megagametophyte is referred to as the central cell and contains two polar nuclei. Examine the slide of a longitudinal section of the mature ovule of Lilium on demonstration. Note the integuments, micropyle, megasporangium, funiculus , egg cell, synergids, polar nuclei and antipodals.