Fertilization ( syngamy ) The fusion of a male gamete with a female gamete to form a zygote the essential process of sexual reproduction .

受精（ 有性 生殖）：一个雌配子和一个雄配子融合形成一个合子，是有性生殖的基础。

Gametes showed intensive positive phototaxis after syngamy motile zygotes showed negative phototaxis .

其配子具有明显的正 趋光性，合子具有负趋光性。