广播电视英语短句 第 283 课：修剪植株-2

Researchers have known since the nineteen thirties that the actively growing tip of a plant releases a hormone called auxin. 自1930S起，研究人员就了解到生长旺盛的植物顶梢会释放出一种被称为茁长素的激素。

This hormone flows down the main stem. 这种激素向下流淌在植物主干内。

Scientists say the auxin has an indirect effect on buds on the side of the stem to prevent branching. 科学家们称这种激素可以间接地阻止主干两侧的芽体分枝。

These buds themselves also produce auxin. 这些芽体自身也产生茁长素。

The research suggests that to grow, they have to be able to export the hormone into the main stem. 这项研究提示说如果要生长，它们必须能够将这种激素输入主干之内。