当植物的花朵开放以后,雄蕊的花粉通过各种途径,飞落到成熟的雌蕊柱头上,花粉受到柱头分泌物的刺激,便开始萌发。花粉首先生出细长的花粉管。花粉管沿着花柱伸入子房,一直达到胚珠。花粉管里有两个精子,一个精子与胚珠里的卵细胞相互融合为合子,另一 When the plant’s flowers open, the stamen pollen by various means, fly down to the mature pistil stigma, pollen by the stigma secretion stimulation, began to germinate. Pollen first gives birth to slender pollen tubes. The pollen tube extends into the ovary along the style until it reaches the ovule. Pollen tube has two sperm, a sperm and ovule in the egg cells merge into zygote, the other