Placeholder Image

字幕表 動画を再生する

  • Wouldn’t expect to come across a plant with strep throat, or pneumonia.

  • But have you ever seen a tree with a big, twisted knot growing out of it?

  • You know what that is?

  • Plant cancer.

  • It’s not super easy to define what cancer is. But in humans, cancer is often described as

  • uncontrolled cell division that can spread into surrounding tissues, forming a tumor.

  • And the plants can get their own version of a tumor.

  • It’s just much harder for it to spread, because of how plants are structured.

  • Still, plant cancer can be harmful, sometimes even fatal.

  • Cancer often -- but not always --

  • starts in humans or other animals because of mutations in a cell’s DNA that mess with the normal cellular growth cycle.

  • A healthy cell will stop dividing when the area around it starts getting crowded,

  • but cancer cells just keep dividing over and over, no matter how little room there is.

  • In plants, a cell can keep dividing, too, not because of genetics,

  • but because of other factors, like an infection or some kind of structural damage.

  • The main advantage that plants have here, though,

  • is that it’s a lot harder for this uncontrolled cell division to spread to other areas.

  • In animals, cancerous cells invade other types of tissue by circulating around in the blood.

  • But plants don’t have true circulatory systems, and the fluids they use for nutrient transport,

  • like sap, don’t have cells in them.

  • And there’s another factor keeping cancerous plant cells in place: the cell wall,

  • a rigid structure that surrounds the outside of the cell and helps the plant stay upright.

  • Those firm cell walls prevent cells from moving around within the plant. So even if it wanted to,

  • a cancerous cell couldn’t break off from a tumor and go spread to other tissues.

  • It’s trapped.

  • Instead, these cells keep dividing in place, over and over again.

  • That’s what forms growths like those funky knots on trees --

  • which are called galls or burls.

  • Since the out-of-control cells are kept so firmly in place,

  • the plant is usually able to live out its life with these growths just fine.

  • But sometimes, they will overwhelm it, and the plant can eventually die.

  • So, sadly, plants do get cancer, too, in a way.

  • It’s just different because theyre plants.

  • Thanks for asking! And did you know that SciShow is now on Patreon?

  • If you want to keep getting answers to questions like this, you can go to Patreon.com/SciShow

  • to learn how you can support us by becoming a SciShow Patron!

Wouldn’t expect to come across a plant with strep throat, or pneumonia.

字幕と単語

ワンタップで英和辞典検索 単語をクリックすると、意味が表示されます

B1 中級

植物はガンになるのか? (Do Plants Get Cancer?)

  • 192 29
    Jack に公開 2021 年 01 月 14 日
動画の中の単語