The transfer of pollen grains from male reproductive organs to ovules is called pollination. Within an ovule, a sperm joins with an egg. The joining of a sperm and egg is fertilization. A zygote is formed by fertilization. Inside the ovule, mitosis occurs many times as the zygote develops into an embryo. The ovule becomes a seed. An embryo is a young growing plant within the seed.
For most species of seed plants, male and female reproductive organs are on the same plant. In some species, the male and female reproductive organs are on separate plants. For reproduction to occur in these species, both male and female plants must be present. One example is holly. There are male and female holly trees. Male and female trees must be planted near each other or seeds will not be produced. Only the female tree produces seeds. Other examples are the gingkos and cycads.
แหล่งข้อมูล: FOCUS ON LIFE SCIENCE. Page 178.
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