书城教材教辅科学读本(英文原版)(套装1-6册)
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第323章 第三册(148)

"And I should think," said Norah, "that the soft, velvety petals of the corolla fold round the young stamens and pistil, and make a smooth delicate covering to save them from injury.""Quite right, both of you," said Fred. "That"s just what teacher told us. When the stamens,anthers, and pistil are able to stand the weather, all the flower leaves open, and those inner parts grow quickly. The ovary has its tiny ovules from the first, but the ovules cannot become actual seeds without the pollen from the anthers. The anthers are the first to ripen, and as they ripen they burst open and scatter their yellow pollen. Some of it falls on the stigma of the pistil, and at once forces its way through its spongy substance till it reaches the ovules in the ovary.

"Now listen while I tell you a very wonderful thing about this pollen. You have seen some of the yellow dust. Think how fine the grains of this pollen must be. What a wonderful thing it is then that each little grain of pollen carries down to the ovules a small drop of fluid. It is this very fluid which changes the ovules into actual seeds.""Let me tell Norah about the bees," said Willie, "for after all I think that is more wonderful still.