Plants can do surprising things. As if the wonders of photosynthesis weren’t enough—producing oxygen from the sun to make nearly all life on Earth possible—humans have collaborated with plants on some mind-blowing projects.
scientists taught spinach to send e-mail; created electric from bushes; And I discovered how they taught them baby Adapting to climate change.
But a new study on tomatoes shows that some of the things humans do to plants also limit their power.
Researchers at the University of Illinois Urbana-Champaign investigated what would happen if tomatoes were visited by ‘friends’ and ‘enemies’ – beneficial soil microbes and caterpillars. Their results take us deep into the communication style of one of the world’s most delicious species.
Esther Ngumbi, assistant professor of integrative biology at the university and co-author of the recently published book to workHe is evangelical about the “gospel of plant chemistry.”
“People tend to think of plants as unintelligent, but our studies have shown that they actively respond to the environment around them using chemistry,” he says.
How do plants communicate?
Ngumbi adds that plant chemistry is the language that plants use to communicate. It takes the form of volatile organic compounds (VOCs), which they produce to affect the outside world.
VOCs can be sent as follows: plants for various reasons – such as signaling an injury; to prepare their defenses or warn each other of threats in the environment. Sometimes humans can also detect these signals; for example, they can smell cut grass.
These chemical messages can also be used to recruit beneficial soil microbes that help plants grow, such as arbuscular mycorrhiza. mushrooms (AMF). Or telling predatory insects that you want a pest gnawing on your leaves to disappear.
“When a caterpillar chews on a leaf, the plant sends out a signal that calls out to the caterpillar’s predators. It’s like a billboard telling them where lunch is,” Erinn Dady, another co-author of the study, told the team. Carl R. Woese Institute for Genomic Biology (IGB).
Since they cannot escape danger, this type of chemical control gives plants the best chance of survival. Understanding the factors that affect VOC emissions helps us help them.
Heirlooms and hybrids: What do tomatoes tell us?
Soil microbes or caterpillars The researchers wanted to examine the collective impact of both friends and foes, as this can influence VOCs.
They looked beyond industrially grown to expand the field of study. tomatoes To test four different varieties commonly grown by small-scale Illinois farmers. On this basis, two hybrids were selected – Mountain Fresh and Valley Girl – and two organic heirlooms, Amish Paste and Cherokee Purple.
For these four varieties, the researchers compared the responses of plants left alone to those exposed to AMF, caterpillars, or both. The eight-week-old plants were kept in an odor-blocking oven bag for an hour to trap the VOCs they emit. This air was then analyzed for its different chemical components.
The results were… a bit confusing. When added separately, AMF and caterpillars reduced volatile emissions from all four plant species. And emissions didn’t change much when both were present. It’s not entirely clear why beneficial fungi reduce VOCs and why plants aren’t more susceptible to eating caterpillars.
But one important finding is that hybrid tomatoes emit lower amounts of VOCs than their heirloom neighbors.
“Heirloom tomatoes — the big, juicy tomatoes we all love — are grown for flavor. Meanwhile, hybrids are grown for large-scale conventional production, which adds a cost to the facility,” Ngumbi says.
“Our study shows that we compromise plant defenses through our cultivation processes.”
Why did the plants chewed by the caterpillars grow larger?
Tomato tests yielded another surprising result, leading researchers to a new line of research.
They also measured the growth of plants above and below ground. soil. Not surprisingly, plants with fungal associations developed more leaves and more complex root structures. Another proof of how incredible and cooperative fungi can be.
“AMF establishes partnerships in more than 80 percent of land plants and establishes a trade in which fungi extract nutrients from the soil. carbon “In Cherokee Purple in particular, we found that AMF could provide additional benefits, including increased growth and increased VOC emissions,” Dady explains.
However, plants treated with caterpillars also showed greater growth.
“These plants had more biomass both in their roots and above ground, which seems counterintuitive because they were actively eaten. I assume they would have less biomass,” Dady told the university site.
“It is possible that the caterpillars triggered a growth response similar to when you prune a tree to encourage new growth.” Ngumbi also suggested that: plants It could continue to grow without being affected by the number of caterpillars. Or that the caterpillars aren’t hungry enough to do real harm.
“There’s a lot going on behind the scenes that we don’t yet understand,” Dady added, and there are many more clues of dialogue that researchers can grasp.