And now for the main event, we have auxin — not you, auxin.

现在关键是素，不是你，是素。

Cytokinin and auxin are often fighting with each other, and sometimes gibberellin and auxin team up to stimulate fruit development.

细胞分裂素和素经常相互争斗，有赤霉素和素合作刺激果实发育。

When a plant's an embryo, auxin helps decide which half of it will become the root and which will be the shoot.

当还是胚胎，素帮助决定哪一半将为根，哪一半将为芽。

Basically, without auxin, a plant would be knocked out… of life!

基本上，没有素，就会失去命！

And so auxin, what auxin does, is it causes cells to lengthen.

而且，素的作用是使细胞伸。

You want to study auxin, it doesn't matter what you call yourself.

你想研究素，叫什么名字并不重要。

Well they use a plant hormone called auxin to do that.

它们使用一种名为素的激素来完这一过程。

So if the sun is over on this side, now the auxin would move in this direction and then the stem in going to bend back like that.

所以如果太阳在这边，素就会朝这个方向移动，然后茎就会弯回去像那样。

Well it could be that auxin was used for another purpose.

好吧，可能是素被用于其他目的。

So what happens to the cells where the auxin is?

那么，素所在的细胞会发什么变化？

And so if the light is over here you can actually see it in this picture, if the light is coming over here, remember what happens in a plant is that the auxin will move away from the light.

因此，如果光线从这边照射过来， 你可以在这张图片中看到，当光线从这边照射， 记住在中会发什么：素会远离光线移动。

Just to get plants to grow but once you had differential movement of oxygen, auxin, excuse me, they you could get growth in response to light.

为了让，一旦你实现了氧气的差异运动，素，抱歉，这样就能根据光照来促进。

Well the cells where the auxin is are going to get longer.

含有素的细胞会变。

What auxin does is auxin will move inside the plant.

素的作用是会在体内移动。

And they do that using auxin.

它们是通过素来实现这一点的。