you wouldn’t expect to come across a plantwith 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 canceris. but in humans, cancer is often described
what color is throat cancer, as uncontrolled cell division that can spreadinto surrounding tissues, forming a tumor. and plants can get their own version of atumor. 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 inhumans or other animals because of mutations in a cell’s dna that mess with the normalcellular growth cycle. a healthy cell will stop dividing when thearea around it starts getting crowded, but cancer cells just keep dividing over and over,no matter how little room there is. in plants, the cell can keep dividing, too,not because of genetics, but because of other factors, like an infection or some kind ofstructural damage. the main advantage that plants have here,though, is that it’s a lot harder for this uncontrolled cell division to spread to otherareas. in animals, cancerous cells invade other typesof 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 cancerousplant cells in place: the cell wall, a rigid structure that surrounds the outside of thecell and helps the plant stay upright. those firm cell walls prevent cells from movingaround within the plant. so even if it wanted to, a cancerous cell couldn’t break offfrom 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 funkyknots on trees -- which are called galls or
burls. since the out-of-control cells are kept sofirmly in place, the plant is usually able to live out its life with these growths justfine. but sometimes, they will overwhelm it, and the plant can eventually die. so, sadly, plants do get cancer, too, in away. it’s just different because they’re
plants. thanks for asking! and did you know that scishowis now on patreon? if you want to keep getting answers to questions like this, you can goto patreon.com/scishow to learn how you can support us by becoming a scishow patron!
