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树木为了吸收阳光,争相长高,同时,在其他方面也有新的变化。在性方面,树木更是向前迈出了一大步,在孢子周围建起了一层壳来保护孢子,这样孢子不再会落到地上,而留在树上发芽。在被称为胚珠的壳内有雌性细胞,雄性细胞则在另一个器官中形成:带有雄性细胞的小原叶体,被称为花粉。在以前花粉叫雄性孢子,花粉在花出现以前就存在了,只是人们在花出现之后才使用花粉这个词。为了能使异性相逢,必须借助风来传送含有游动精子的花粉。花粉漫无边际地飘游,有时能落到一个胚珠上,接触后胚珠会变软胶化;而后,胚珠部分地变成液体,以使花粉游动,与卵球会合。尽管花粉已经被风移动了,但它的游动特点犹在。然而,植物还是渐渐地离开了大海。
In order to absorb sunlight, trees compete for growth. At the same time, there are new changes in other areas. In terms of sexuality, the trees have taken a big step forward. A shell was built around the spores to protect the spores so that the spores would no longer fall to the ground and stay on the trees to germinate. In the shell called the ovule, there are female cells, and the male cells are formed in another organ: the small protoplast with male cells is called pollen. In the past pollen called male spores, pollen had existed before the emergence of flowers, but people only use the word pollen after the emergence of flowers. In order to enable the opposite sex to meet, the wind must be used to deliver pollen containing motile sperm. The pollen floats endlessly, sometimes falling onto an ovule, and the ovule becomes soft and gelatinized after contact; then, the ovule partially becomes liquid, so that the pollen swims and meets the ovoid ball. Although pollen has been moved by the wind, its swimming characteristics are still there. However, the plant still gradually left the sea.