Can plants get cancer?

Can plants also get cancer? Today, let’s follow the popular science writer Shi Jun, a doctor of botany from the Chinese Academy of Sciences, to learn about this question.

The topic we are going to talk about today is "Why Plants Don't Get Cancer". Of course plants can get cancer, but first we need to clarify what cancer is.

01

What is cancer?

What does plant “cancer” look like?

Although the name cancer is familiar to everyone, not many people truly understand its meaning.

"Cancer is a disease" seems to be nonsense, let's add a modifier: cancer is a disease caused by some cells in the body deviating from the death program . Doesn't it sound interesting?

Just like tumors can occur in animals, they can also occur in plants. These tumor cells in plants can also separate from normal tissues, lose their normal physiological functions, and become a growth burden for the plants. To some extent, this can also be called "cancer" in plants.

We can see many cancers in plants around us, for example, some plants have galls on their leaves; some plants have large tumors on their trunks; some oil tea fruits have turned into balloon-like tea bags. However, even if a plant has cancer, it will not affect the normal growth of the plant body, or it will have little effect on the normal reproduction of most plants.

So the question is, why are humans so afraid of cancer, but plants can live for so many years with cancer?

Under normal circumstances, every cell in our body has a lifespan. They will go through the process of division, growth, and apoptosis , which ensures that the cells of each tissue and organ are constantly renewed and always full of fighting spirit. However, some "problem" cells and aging cells that should have apoptosis escape the apoptosis program for various reasons and achieve immortality.

Sounds great, right? These immortal cells bring us big trouble because they become uncontrolled troublemakers. What's more troublesome is that these cells not only have no physiological functions themselves, but also occupy the living space of normal cells, eventually causing the body to collapse .

In fact, whether it is an animal or a plant, there are always mistakes in the process of cell proliferation. In theory, as long as the cells in the body do not make mistakes, the organism can survive forever, just like a car can theoretically continue to drive on the road if it does not have any problems.

The secret to living a long life is very simple: as long as there is nothing wrong, everything will be fine. If there is a problem, fix it quickly.

But it is easier said than done, because there are always problems with the DNA that life replicates, and the ability of the protein that replicates DNA also declines. Coupled with the influence of the external environment, once the aging period is entered, the entire body will collapse.

For example, for us humans, as we age, the chance of getting sick will greatly increase, some organs will lose certain functions, and the human body will end.

Recently, scientists believe that the life span of an organism is related to the telomeres on the chromosomes: the length of the telomeres determines the survival time of the organism. As we age, the telomeres will become shorter and shorter, like a countdown timer, and when it returns to zero, it is the end of life.

Note that this does not mean that errors in DNA replication cannot be repaired, but from the perspective of life evolution, the most important mission of biological individuals is to reproduce and spread genes. Therefore, instead of spending a lot of energy to repair errors, it is better to seize the time to make your genes better inherited and spread. This is a result of evolution.

02

Plants are more "calm" in the face of aging

Unlike humans who come and go in a hurry, plants grow slowly, so the probability of error is also lower. Of course, the more critical factor is that plants are constructed organisms , even if some branches, leaves, or even the entire plant body have errors, it is not a big deal for the big tree.

What does it mean that plants are called building blocks? It means that different organs have a lot of "backups" . For example, if one part of the leaves, branches, or roots is damaged, there are still other parts. But it's not the same for humans. If the heart or brain is damaged, these are big problems. Even if a small part of the intestine is damaged, it is difficult to fully recover. For plants, these problems can be solved.

So we often see many old trees with half of them dead, but the other half is still lush and green. In other words, even if the heart of the tree is completely rotten, with only the bark left, the crown can still be lush and green. Not to mention a big tumor on the trunk, which is not a big deal for plants. This is the huge difference between trees and humans.

03

Positive "cancer" in plants

In some cases, some special plant "cancers" actually have some positive effects on plant reproduction, such as the case of rhizobia infecting legumes. After being infected by rhizobia, many round nodules will grow on the roots of legumes. Although the nodules will consume some nutrients from the plant, the rhizobia will use nitrogen in the air to synthesize nitrogen fertilizers needed by the plants for their growth. In this way, the nodules of legumes are actually good "tumors".

In some cases, we like the "cancer" tissue produced by plants. For example, corn truffles are corn kernels infected with smut fungus . The large kernels cannot germinate into corn seedlings, but they can become delicious ingredients.

The wild rice , a popular vegetable in the south, is in a similar situation. After being infected by smut, the stems of the wild rice become thick, large and plump. Although these wild rices infected with smut can no longer produce wild rice , they can provide very delicious vegetables, that is, wild rice. Because of this, it is increasingly valued by humans. Under human care, these infected wild rices live very well.

So plants can also get cancer, but we humans just don’t understand the troubles of plants.

Reviewer: Wang Kang, Director of Beijing Botanical Garden Science Center, Professor-level Senior Engineer

Source: This content is produced by the Science Popularization China Creation and Cultivation Program

The cover image of this article is from the copyright gallery, and the image content is not authorized for reproduction