News
Sunflowers make small moves to maximize their Sun exposure – physicists can model them to predict how they grow
Charles Darwin’s detailed observations of plant movements, such as sunflower circumnutation and self-organization, reveal how randomness helps plants optimize growth and adapt to their environments. Sunflowers!
Last Updated on March 6, 2026 by Daily News Staff
Chantal Nguyen, University of Colorado Boulder
Sunflowers make small moves to maximize their Sun exposure – physicists can model them to predict how they grow
Most of us aren’t spending our days watching our houseplants grow. We see their signs of life only occasionally – a new leaf unfurled, a stem leaning toward the window.
But in the summer of 1863, Charles Darwin lay ill in bed, with nothing to do but watch his plants so closely that he could detect their small movements to and fro. The tendrils from his cucumber plants swept in circles until they encountered a stick, which they proceeded to twine around.
“I am getting very much amused by my tendrils,” he wrote.
This amusement blossomed into a decadeslong fascination with the little-noticed world of plant movements. He compiled his detailed observations and experiments in a 1880 book called “The Power of Movement in Plants.”
In one study, he traced the motion of a carnation leaf every few hours over the course of three days, revealing an irregular looping, jagged path. The swoops of cucumber tendrils and the zags of carnation leaves are examples of inherent, ubiquitous plant movements called circumnutations – from the Latin circum, meaning circle, and nutare, meaning to nod.
Circumnutations vary in size, regularity and timescale across plant species. But their exact function remains unclear.
I’m a physicist interested in understanding collective behavior in living systems. Like Darwin, I’m captivated by circumnutations, since they may underlie more complex phenomena in groups of plants.
Sunflower patterns
A 2017 study revealed a fascinating observation that got my colleagues and me wondering about the role circumnutations could play in plant growth patterns. In this study, researchers found that sunflowers grown in a dense row naturally formed a near-perfect zigzag pattern, with each plant leaning away from the row in alternating directions.
This pattern allowed the plants to avoid shade from their neighbors and maximize their exposure to sunlight. These sunflowers flourished.
Researchers then planted some plants at the same density but constrained them so that they could grow only upright without leaning. These constrained plants produced less oil than the plants that could lean and get the maximum amount of sun.
While farmers can’t grow their sunflowers quite this close together due to the potential for disease spread, in the future they may be able to use these patterns to come up with new planting strategies.
Self-organization and randomness
This spontaneous pattern formation is a neat example of self-organization in nature. Self-organization refers to when initially disordered systems, such as a jungle of plants or a swarm of bees, achieve order without anything controlling them. Order emerges from the interactions between individual members of the system and their interactions with the environment.
Somewhat counterintuitively, noise – also called randomness – facilitates self-organization. Consider a colony of ants.
Ants secrete pheromones behind them as they crawl toward a food source. Other ants find this food source by following the pheromone trails, and they further reinforce the trail they took by secreting their own pheromones in turn. Over time, the ants converge on the best path to the food, and a single trail prevails.
But if a shorter path were to become possible, the ants would not necessarily find this path just by following the existing trail.
If a few ants were to randomly deviate from the trail, though, they might stumble onto the shorter path and create a new trail. So this randomness injects a spontaneous change into the ants’ system that allows them to explore alternative scenarios.
Eventually, more ants would follow the new trail, and soon the shorter path would prevail. This randomness helps the ants adapt to changes in the environment, as a few ants spontaneously seek out more direct ways to their food source.
In biology, self-organized systems can be found at a range of scales, from the patterns of proteins inside cells to the socially complex colonies of honeybees that collectively build nests and forage for nectar.
Randomness in sunflower self-organization
So, could random, irregular circumnutations underpin the sunflowers’ self-organization?
My colleagues and I set out to explore this question by following the growth of young sunflowers we planted in the lab. Using cameras that imaged the plants every five minutes, we tracked the movement of the plants to see their circumnutatory paths.
We saw some loops and spirals, and lots of jagged movements. These ultimately appeared largely random, much like Darwin’s carnation. But when we placed the plants together in rows, they began to move away from one another, forming the same zigzag configurations that we’d seen in the previous study.
We analyzed the plants’ circumnutations and found that at any given time, the direction of the plant’s motion appeared completely independent of how it was moving about half an hour earlier. If you measured a plant’s motion once every 30 minutes, it would appear to be moving in a completely random way.
We also measured how much the plant’s leaves grew over the course of two weeks. By putting all of these results together, we sketched a picture of how a plant moved and grew on its own. This information allowed us to computationally model a sunflower and simulate how it behaves over the course of its growth.
A sunflower model
We modeled each plant simply as a circular crown on a stem, with the crown expanding according to the growth rate we measured experimentally. The simulated plant moved in a completely random way, taking a “step” every half hour.
We created the model sunflowers with circumnutations of lower or higher intensity by tweaking the step sizes. At one end of the spectrum, sunflowers were much more likely to take tiny steps than big ones, leading to slow, minimal movement on average. At the other end were sunflowers that are equally as likely to take large steps as small steps, resulting in highly irregular movement. The real sunflowers we observed in our experiment were somewhere in the middle.
Plants require light to grow and have evolved the ability to detect shade and alter the direction of their growth in response.
We wanted our model sunflowers to do the same thing. So, we made it so that two plants that get too close to each other’s shade begin to lean away in opposite directions.
Finally, we wanted to see whether we could replicate the zigzag pattern we’d observed with the real sunflowers in our model.
First, we set the model sunflowers to make small circumnutations. Their shade avoidance responses pushed them away from each other, but that wasn’t enough to produce the zigzag – the model plants stayed stuck in a line. In physics, we would call this a “frustrated” system.
Then, we set the plants to make large circumnutations. The plants started moving in random patterns that often brought the plants closer together rather than farther apart. Again, no zigzag pattern like we’d seen in the field.
But when we set the model plants to make moderately large movements, similar to our experimental measurements, the plants could self-organize into a zigzag pattern that gave each sunflower optimal exposure to light.
So, we showed that these random, irregular movements helped the plants explore their surroundings to find desirable arrangements that benefited their growth.
Plants are much more dynamic than people give them credit for. By taking the time to follow them, scientists and farmers can unlock their secrets and use plants’ movement to their advantage.
Chantal Nguyen, Postdoctoral Associate at the BioFrontiers Institute, University of Colorado Boulder
This article is republished from The Conversation under a Creative Commons license. Read the original article.
STM Daily News is a vibrant news blog dedicated to sharing the brighter side of human experiences. Emphasizing positive, uplifting stories, the site focuses on delivering inspiring, informative, and well-researched content. With a commitment to accurate, fair, and responsible journalism, STM Daily News aims to foster a community of readers passionate about positive change and engaged in meaningful conversations. Join the movement and explore stories that celebrate the positive impacts shaping our world.
https://stmdailynews.com/category/stories-this-moment
Food Truths
The Truth About the “Chemical” in McDonald’s Burger Buns: Should Consumers Be Concerned?
What’s in the Burger Buns:The “yoga mat chemical” controversy changed how consumers view food additives. Here’s what azodicarbonamide is, why McDonald’s removed it, and what the science actually says.
For years, headlines and social media posts have warned consumers about a so-called “yoga mat chemical” found in hamburger buns served by major fast-food chains. The claims sparked widespread concern, prompted petitions, and eventually led several restaurant companies—including McDonald’s—to change their recipes.
But what was the chemical, and is there actually a health risk today?
What Was the Controversial Ingredient?
The ingredient at the center of the controversy was azodicarbonamide (ADA), a chemical used as a dough conditioner. It helped improve the texture of bread, making dough easier to handle and producing softer, more consistent buns.
Ironically, the same compound is also used in manufacturing certain foamed plastics, including some yoga mats and shoe soles. That connection gave rise to the viral nickname, “the yoga mat chemical.”
While the comparison was technically accurate, it also lacked important context. Food-grade azodicarbonamide and industrial applications are very different, and many chemicals have multiple uses across industries.
Why Did People Become Concerned?
The concern wasn’t simply that ADA was used in food. Scientists focused on what happens during baking.
When bread is baked, most azodicarbonamide breaks down into other compounds. Some laboratory studies involving animals raised questions about one of these breakdown products, called semicarbazide (SEM), when administered in high doses.
Those findings prompted some countries to take a more cautious regulatory approach.
Why Is It Banned in Some Countries?
The European Union and Canada do not permit azodicarbonamide as a flour treatment agent. Their food safety policies often follow the precautionary principle, removing ingredients when safer alternatives exist or when scientific uncertainty remains.
In contrast, the U.S. Food and Drug Administration has determined that azodicarbonamide is safe when used within approved limits.
These differing regulations don’t necessarily mean one side believes the ingredient is dangerous while the other believes it is harmless. Instead, they reflect different philosophies about regulating food additives.
Does McDonald’s Still Use It?
No.
McDonald’s removed azodicarbonamide from its U.S. hamburger buns in 2014 following growing consumer demand for simpler ingredient lists.
Today’s buns no longer contain the ingredient, joining a broader trend among food manufacturers to eliminate additives that have become controversial with consumers.
Are There Other Ingredients Consumers Should Know About?
Modern commercial bread still contains ingredients designed to improve freshness, texture, and shelf life.
These may include:
- Calcium propionate to prevent mold
- Ascorbic acid (Vitamin C) as a dough conditioner
- Enzymes that improve consistency
- Emulsifiers that help maintain softness
These ingredients have been evaluated by food safety agencies and are generally recognized as safe when used according to regulations.
The Bigger Health Picture
Nutrition experts generally agree that focusing on one ingredient can distract from the larger issue.
The greatest health risks associated with fast food are more closely linked to:
- High sodium intake
- Excess saturated fat
- Added sugars
- Large portion sizes
- Frequent consumption of ultra-processed foods
An occasional fast-food meal is unlikely to determine someone’s long-term health. Overall dietary patterns, physical activity, sleep, and other lifestyle factors have a much greater impact.
Consumer Awareness Is Changing the Food Industry
Whether or not an ingredient poses a measurable health risk, public concern can influence corporate decisions.
Over the past decade, many food companies have reformulated products to remove controversial ingredients, reduce artificial additives, and simplify ingredient labels. In many cases, those changes have been driven as much by consumer preferences as by regulatory requirements.
The Bottom Line
The “yoga mat chemical” story captured public attention because it combined science, food safety, and memorable marketing. While azodicarbonamide was once used in some hamburger buns, including those supplied to McDonald’s, the company removed it from its U.S. buns years ago.
Current evidence suggests consumers are better served by paying attention to their overall diet rather than worrying about a single ingredient that has already disappeared from many products.
Being an informed consumer means looking beyond the headlines, understanding the science, and recognizing that nutrition is about the complete picture—not just one ingredient.
Related External Links
- U.S. FDA – Food Additives & GRAS Ingredients Information for Consumers
- U.S. FDA – Food Additives and Petitions
- FDA – Azodicarbonamide (ADA) Food Substance Database
- Electronic Code of Federal Regulations – 21 CFR §172.806 (Azodicarbonamide)
- FDA – Types of Food Ingredients and Why They’re Used
- Health Canada – Permitted Flour Treatment Agents
- McDonald’s USA – Nutrition Calculator & Ingredient Information
🍴 What’s your favorite food, recipe, or dining spot? Tell us in the comments! Then subscribe to the STM Daily News Food and Drink newsletter for fresh recipes, restaurant news, food trends, and delicious stories delivered straight to your inbox. Join our growing community of food lovers today!
STM Blog
Association of Black Cardiologists to Celebrate Legacy and Leadership at 16th Annual Spirit of the Heart Awards
The Association of Black Cardiologists (ABC) is bringing its signature celebration of impact back to New York City this fall—spotlighting leaders and organizations working to make cardiovascular care more equitable, more accessible, and more effective. The 16th Annual Spirit of the Heart Awards Program & Fundraiser is set for Saturday, October 3, 2026 (6:00 p.m.–9:00 p.m.) at Cipriani Wall Street in Manhattan.
For ABC, the evening is more than a high-profile awards program. It’s a cornerstone fundraising event that helps power the organization’s year-round work—supporting medical student scholarships, fellowships, education, and programs designed to strengthen the pipeline of diverse clinicians and researchers while improving outcomes in communities that carry a disproportionate burden of heart disease.
A fundraising night with long-term stakes
ABC leaders say the Spirit of the Heart Awards is built around a simple idea: celebrating progress while investing in the people who will drive the next wave of change.
Event co-chair Icilma Fergus, MD—Director of the Cardiovascular Disparities Center at Mount Sinai Medical Center and Board Chair of ABC—framed the night as a forward-looking commitment.
“This gathering is about more than one evening of celebration; it is about investing in the future of cardiovascular health for years to come,” Fergus said in the announcement. She added that the support generated through the event helps expand opportunities for aspiring clinicians, researchers, and leaders whose work can transform care and improve lives nationwide.
Honorary Chairperson: Samin K. Sharma, MD
ABC announced Samin K. Sharma, MD as the event’s Honorary Chairperson. Sharma serves as Chief of Clinical Cardiology, Director of the Cardiovascular Clinical Institute, and the Anandi Lal Sharma Professor of Medicine at the Icahn School of Medicine at Mount Sinai.
In the release, ABC highlighted Sharma’s international reputation in interventional cardiology and physician education, noting that he has trained cardiovascular specialists from around the world while advancing the field through research, mentorship, and patient care.
“I am honored to serve as Honorary Chairperson for this important event,” Sharma said. “The Spirit of the Heart Awards Program reflects the power of partnership, philanthropy, and leadership to advance cardiovascular health.”
A full weekend of impact, including policy
The awards program is part of a broader weekend of programming. On Friday, October 2, ABC will host its Annual Policy Pulse Summit at Venable LLP in New York City, convening leaders to discuss policy issues shaping the future of cardiovascular health.
What to expect at the Spirit of the Heart Awards
ABC is positioning the evening as both a celebration and a community gathering—bringing together leaders from healthcare, philanthropy, industry, and advocacy.
The event will be co-emceed by:
- Sandra Bookman, award-winning journalist and anchor of Eyewitness News on ABC7/WABC-TV New York
- Thomas Cunningham IV, President and Chief Content Officer of BrandCunningham
The program is expected to include:
- Presentation of the Spirit of the Heart Awards
- Recognition of medical student scholarship recipients
- Special guest appearances
- A live auction
- Musical entertainment
Event co-chair Barbara Hutchinson, MD, PhD, President of Chesapeake Cardiac Care, emphasized the role of sustained collaboration in moving the needle on heart health.
“The Spirit of the Heart Awards Program is a reminder that lasting progress in cardiovascular health is achieved through vision, partnership, and sustained commitment,” Hutchinson said.
How to attend, sponsor, or support
ABC is directing attendees and supporters to its event site for tickets, sponsorship opportunities, and donations:
- Event info / tickets / sponsorship / donations: https://abcardioevents.org
About the Association of Black Cardiologists
Founded on the belief that “every heart counts,” the Association of Black Cardiologists works to promote prevention and treatment of cardiovascular disease and to advance health equity by eliminating disparities. ABC’s membership is open to all, regardless of race, ethnicity, or vocation. The organization’s work spans education, advocacy, research, patient and community outreach, and leadership development.
- Organization website: https://abcardio.org
Source and media contact
- Press release source (PRNewswire): https://www.prnewswire.com/news-releases/association-of-black-cardiologists-to-celebrate-legacy-and-leadership-at-16th-annual-spirit-of-the-heart-awards-302206000.html
Media Contact (from the release):
- Akeia Blue, VP of Communications
- 419395@email4pr.com
- 240-321-9227
📰 Enjoying STM Daily News? Join the conversation!
💬 Leave a comment, share your thoughts, and subscribe to our newsletter for the latest stories, updates, and “News You Can Use This Moment!” delivered to your inbox.
Stay connected with STM Daily News!
Food and Beverage
Millions of Eggs Recalled Over Possible Salmonella Risk: What Consumers Need to Know
A major egg recall is affecting nearly 1.6 million dozen eggs sold under several popular brands. Here’s how to determine if your eggs are included and what steps to take if they are.
News You Can Use This Moment!
Consumers are being urged to check their refrigerators after a major recall involving nearly 1.6 million dozen shell eggs due to the potential presence of Salmonella Enteritidis, a bacterium that can cause serious foodborne illness.
The voluntary recall, announced by Midwest Poultry Services, L.P., affects white shell eggs and brown cage-free eggs produced at two Texas farms and distributed between June 6 and July 3, 2026. According to the U.S. Food and Drug Administration (FDA), the eggs were sold through grocery stores and foodservice distributors in Texas, Louisiana, Oklahoma, Arkansas, Mississippi, and New Mexico.
What Brands Are Included?
The recalled eggs were sold under several familiar brand names, including:
- Kroger
- Simple Truth
- Brookshire’s
- Country Morning
- Sunups
Not every carton under these brands is affected. Consumers should look for:
- Plant Code: P-1950 or 0840962
- Julian Dates: 157 through 184
- Best By/Sell By Dates: July 20, 2026, through August 17, 2026
Why the Recall Matters
Salmonella can cause symptoms including:
- Diarrhea
- Fever
- Stomach cramps
- Nausea
- Vomiting
Symptoms typically begin 12 to 72 hours after eating contaminated food and usually last four to seven days. While many healthy adults recover without treatment, infections can become severe in young children, older adults, pregnant women, and people with weakened immune systems.
The FDA and the Centers for Disease Control and Prevention (CDC) are investigating a multistate outbreak involving 98 confirmed illnesses across 17 states, resulting in 26 hospitalizations. No deaths have been reported. Investigators say the recalled eggs are linked to part of the outbreak, although they do not account for every reported illness.
What Should You Do?
If you have eggs matching the recalled codes:
- Do not eat them.
- Return them to the store for a refund or dispose of them safely.
- Wash your hands thoroughly after handling the carton.
- Clean and sanitize any refrigerator shelves, containers, or kitchen surfaces the eggs may have touched.
If you have already eaten the eggs and develop symptoms of Salmonella infection, contact your healthcare provider, especially if symptoms are severe or persist.
Are Arizona Consumers Affected?
The recalled products were officially distributed in six states, and Arizona is not listed among the primary distribution states. However, because food products can move through wholesalers, travelers, or secondary retailers, Arizona consumers who recently purchased eggs while traveling—or who received eggs from family or friends in affected states—should still check the carton codes.
The Bottom Line
Food recalls are an important part of protecting public health. Taking a few moments to inspect the eggs in your refrigerator could help prevent a serious illness. If your carton matches the recalled plant codes and date range, don’t take the risk—return it or throw it away.
STM Daily News will continue to monitor this developing story and provide updates as additional information becomes available.
Related Resources
- FDA Recalls, Market Withdrawals & Safety Alerts
- FDA Foodborne Illness Outbreak Investigations
- CDC: Salmonella Information
- FoodSafety.gov Consumer Resources
