书城教材教辅科学读本(英文原版)(套装1-6册)
47723000000328

第328章 第三册(153)

"Can you tell me, Fred, all about the way the little seed germ grows till it becomes a plant, able to take care of itself ?" asked Norah. "I learned so many new things from what you told me about the seeds, that I should so much like to know just how that little germ grows.""Well, I think I can tell you something about it," said Fred, "for that was our lesson this morning.

"You know that every seed contains in itself the germ of a little plant, with root, stem, leaves, onlywaiting for an opportunity to grow. Teacher showed us some peas which he was growing in flowerpots; some were only just starting, others were quite little plants with leaves.

"After the seeds have been in the damp soil for some time the first effect of the moisture is to cause the testa to swell up and wrinkle till at last it bursts. While this has been going on, the warmth and moisture together have made the tiny germ wake up, as it were, from its long sleep and begin to stretch itself out. It happens, you see, that the testa splits just at the time when the germ has woke up, is beginning to grow, and wants more room.