It's like a little magnetic "nom, nom."
- Venus flytrap leaves shut in response to physical touch, salt water, or thermal stimuli.
- A team of scientists from Berlin have captured the magnetic charge that accompanies the closing of the plant's trap.
- Incredibly sensitive, non-invasive atomic magnetometers picked up the elusive signal.
For many children, the revelation that there's such a thing as a Venus Flytrap, Dionaea muscipula, is an amazing moment. The choppers of the sneaky plant predators are like something out of a fairy tale gone wrong. Adults can't help but be fascinated by them too, and now scientists at Johannes Gutenberg University Mainz (JSU) and the Helmholtz Institute Mainz in Germany have discovered something new that's surprising about these little demons: Every time they entrap prey, they give off a measurable magnetic charge.
"We have been able to demonstrate that action potentials in a multicellular plant system produce measurable magnetic fields, something that had never been confirmed before," says lead author Anne Fabricant.
Guilt as magnetically charged
The plants' bivalved snap trap (left), side view of a destained trap lobe (right)
Credit: Fabricant, et al./Scientific Reports
According to Fabricant, the finding isn't that much of a shock: "Wherever there is electrical activity, there should also be magnetic activity," she tells Live Science. And it is electrical activity in the form of action potentials that trigger its maw—really a pair of leaf lobes—to close when a hapless bug lands inside them, attracted by the nectar with which the plants bait their trap.
Along the inner surfaces of the lobes are trichomes, hair-like projections that cause the trap to close when they're disturbed by prey. One touch of a trichome is unlikely to cause the trap to shut — perhaps a mechanism that helps the plant avoid wasting energy on false alarms. A couple of touches, though, and it's chow time. The lobes come together as the bristles at their edges intertwine to help contain the prey. As the traps compress the trapped insect, its own secretions such as uric acid cause the trap to shut even more tightly, and then digestion begins.
In any event, just because the JSU researchers had reason to suspect the plant would give off a magnetic charge, catching it doing so was not a simple task.
Reading the Venus flytrap's magnetic output
Average action potential and corresponding magnetic signals
Credit: Fabricant, et al./Scientific Reports
"The problem," says Fabricant, "is that the magnetic signals in plants are very weak, which explains why it was extremely difficult to measure them with the help of older technologies." Still, where there's a will: "You could say the investigation is a little like performing an MRI scan in humans."
It's not just trichome flicks that trigger the trap — it will also close if triggered by salt-water, or with an application of either hot or cold thermal energy. The researchers applied heat via a purpose-built Peltier device that wouldn't introduce any background magnetic noise to mask or overwhelm the faint magnetic signal they were seeking. For the same reason, the experiments were conducted in a magnetically shielded room at Physikalisch-Technische Bundesanstalt (PTB) in Berlin.
The researchers used atomic magnetometers to measure the planets magnetic charges. The atomic magnetometer is a glass cell containing a vapor of rubidium atoms. When the traps were triggered, the magnetic charges released changed the spins of the atoms' electrons.
The researchers picked up magnetic signals at an amplitude of up to 0.5 picoteslas. "The signal magnitude recorded is similar to what is observed during surface measurements of nerve impulses in animals," says Fabricant. It's over a million times weaker than the Earth's own magnetic field.
Other researchers have detected magnetic charges coming the firing of animal nerves — including within our own brain. The phenomenon is referred to as "biomagnetism." Since other plants have action potentials, they may also generate biomagnetism, though less research has been done on them.
It's to other plants that the attention of the JSU team now turns, as they go looking for even smaller magnetic charges from other species. In addition to providing new understanding of nature's use of electricity, non-invasive detection technologies such as the one employed by the group could one day be utilized for more insightful monitoring of crops as they respond to thermal, pest, and chemical influences.
Researchers document the first example of evolutionary changes in a plant in response to humans.
- A plant coveted in China for its medicinal properties has developed camouflage that makes it less likely to be spotted and pulled up from the ground.
- In areas where the plant isn't often picked, it's bright green. In harvested areas, it's now a gray that blends into its rocky surroundings.
- Herbalists in China have been picking the Fritillaria dealvayi plant for 2,000 years.
There are a growing number of examples of animals' evolutionary path diverting around humans and human encroachment. From the increase of tuskless elephants to changing fox snouts, this biological trend, though worrying, is well-documented. Now researchers in China have discovered a wildly growing plant that has adapted by developing camouflage that makes it less likely to get picked by human hands. Nobody likes us.
The study was conducted by botanist Yang Niu of the Kunming Institute of Botany in China, in collaboration with sensory ecologist Martin Stevens of the University of Exeter in England. "It's remarkable to see how humans can have such a direct and dramatic impact on the coloration of wild organisms, not just on their survival but on their evolution itself," Stevens tells University of Exeter News.
The research is published in Current Biology.
The plant is Fritillaria dealvayi, and its bulbs are harvested by Chinese herbalists, who grind it into a powder that treats coughs. The cough powder sells for the equivalent of $480 per kilogram, with a kilogram requiring the grinding up of about 3,500 bulbs. The plant is found in the loose rock fields lining the slopes of the Himalayan and Hengduan mountains in southwestern China.
As a perennial that produces just a single flower each year after its fifth season, it seems Fritillaria used to be easier to find. In some places its presence is betrayed by bright green leaves that stand out against the rocks among which which it grows. In other places, however, its leaves and stems are gray and blend in with the rocks. What's fascinating is that the bright green leaves are visible in areas in which Fritillaria is relatively undisturbed by humans while the gray leaves are (just barely) visible in heavily harvested areas. Same plant, two different appearances.
2/2: The picture on the left shows a Fritillaria delavayi in populations with high harvest pressure, and the one on… https://t.co/oriBNZGcsV— University of Exeter News (@University of Exeter News)1605891854.0
How we know we're the cause
There are other camouflaging plants, but the manner in which Fritillaria has developed this trait strongly suggests that it's a defensive response to being picked. "Many plants seem to use camouflage to hide from herbivores that may eat them — but here we see camouflage evolving in response to human collectors."
"Like other camouflaged plants we have studied," Niu says, " we thought the evolution of camouflage of this fritillary had been driven by herbivores, but we didn't find such animals." His close examination of Fritillaria leaves revealed no bite marks or other signs of non-human predation. "Then we realized humans could be the reason."
In any event, says Professor Hang Sun the Kunming Institute, "Commercial harvesting is a much stronger selection pressure than many pressures in nature."
Credit: maron/Adobe Stock
Since herbalists have been plucking Fritillaria from the rocks for 2,000 years, one might hope a record would exist that could allow researchers to identify areas in which the plant has been most thoroughly picked. There is no such documentation, but Liu and Stevens were able to acquire this type of information for five years (2014–2019), tracking the harvests at seven Fritillaria study sites. This allowed them to identify those areas in which the plant was most heavily harvested. These also turned out to be the locations with the gray-leaf variant of Fritillaria.
Further supporting the scientists' conclusion that gray Fritillaria was more likely to evade human hands and live long enough to reproduce was that participants in virtual plant-identification tests confirmed the species was hard to spot in the wild.
"It's possible that humans have driven evolution of defensive strategies in other plant species, but surprisingly little research has examined this," Stevens notes.
Hang Sun says such studies make clear that humans have become drivers of evolution on our planet: "The current biodiversity status on the earth is shaped by both nature and by ourselves."
Medicago is growing a SARS-CoV-2 vaccine candidate in a relative of the tobacco plant right now.
- Canadian biotech company Medicago is growing a vaccine candidate in Nicotiana benthamiana.
- An Australian relative to tobacco, plant-based vaccines could be cheaper and more reliable than current methods.
- Medicago just completed phase 3 clinical trials of an influenza vaccine, which could be a game-changer for vaccine production.
One of the biggest fears around vaccines, however unwarranted, is that they're "unnatural." Adjuvants that help improve vaccine response, such as alum, squalene, and paraffin oil, have been demonized by the anti-vaxx movement. This trend has resulted in over one-third of Americans claiming they won't get a SARS-CoV-2 vaccine when one is produced.
With over 200 vaccine trials underway, chances that 2021 will result in a reliable vaccine are high. Those worried about the "unnatural" means by which vaccines are produced may take comfort in a groundbreaking new development.
In July, Canadian biotech company Medicago began phase 1 clinical trials using a vaccine candidate that's grown in Nicotiana benthamiana, an Australian plant that closely resembles tobacco. The plant's naturally poor immune system allows virus-like particles (VLPs) to flourish. Medicago CEO Bruce Clark says the plant acts like a "bioreactor" that produces usable material in a matter of weeks.
Many vaccines are traditionally incubated in chicken eggs. The annual influenza vaccination is a common example. The process is delicate, however: US government facilities are hidden and highly secure. This method is costly, as every dose requires at least one egg. Tens of millions of chicken eggs are used for this purpose in America every year.
There's another important cost: time. While a plant-developed VLP vaccine takes roughly two months to develop, egg vaccines take up to a half-year to produce. With plants, you get a vaccine quicker and without ethical concerns for the strain on chickens.
By contrast, Nicotiana benthamiana grows in rugged environments throughout Australia. It can grow up to five feet tall. The frail leaves have made it an exceptional candidate for plant research and have been used for decades in plant virology. An experimental drug, ZMapp, developed to treat Ebola, was designed using this plant. While not without risks, the WHO claims ZMapp's benefits outweigh the risks, and has approved its usage in cocktail treatments.
Credit: alphaspirit / Adobe Stock
Clark says it's important to attack the novel coronavirus from all sides.
"Creating a sufficient supply of COVID-19 vaccines within the next year is a challenge which will require multiple approaches, with different technologies. Our proven plant-based technology is capable of contributing to the collective solution to this public health emergency."
Unlike many common vaccines, VLP vaccines contain no genetic material. You won't get infected by it, which is always a risk in live vaccines.
This SARS-CoV-2 vaccine is not the only project on Medicago's hands. The company just completed phase 3 clinical trials on an influenza. While no plant-based vaccine has been approved for use, the company hopes to replace the more cumbersome and expensive egg-based model, or at least offset some of the costs of that model. The plant model could help researchers adapt more quickly to the ever-changing influenza strains each season.
Plants offer a wonderful alternative to the current vaccination model. Besides price, VLP vaccines scale much easier and faster. If the SARS-CoV-2 vaccine works, Medicago believes they can produce a billion doses a year, by far the most ambitious yield to date. At a time when speed, cost, and reliability are all essential factors in vaccine development, we should put tobacco to better use: healing instead of harming.
Stay in touch with Derek on Twitter and Facebook. His new book is "Hero's Dose: The Case For Psychedelics in Ritual and Therapy."
Modern crops have been optimized for a lot of things, but not for climate change.
- Growers are struggling to protect their crops from failure as conditions change due to global warming.
- Modern crops lack the fortifying genetic diversity of their ancestors.
- Scientists publish a new guide for strengthening crops through the reintroduction of wild-variety traits based on the latest science.
The climate we've known for thousands of years is going, going, gone. There are few, if any, places where weather patterns haven't changed and aren't continuing to do so. As we witness increasingly dramatic weather events and climate conditions unfold, there's an arguably even more significant climate crisis occurring in agriculture.
Methods that have served growers well in the past are now jeopardizing the world's food supply, not to mention the growers' livelihoods. Centuries of breeding have helped plants thrive and endowed them with characteristics that enhance their appeal in the marketplace. This crop optimization comes at a cost, however: A lack of the genetic diversity that might help them adapt to rapidly changing climate conditions. Many of these crops have been bred to grow well in a climate that no longer exists.
"When the human race first domesticated crops, the climate and environment were completely different — what we are seeing in the last 50 years is a rapid change in climate. The world is now frequently facing catastrophic climate events like droughts and in the UK we are now seeing some crops being harvested up to a month earlier than they used to be." — Dr. Rocio Perez-Barrales, University of Portsmouth
Clearly, it's time to rethink agriculture. Now, scientists from the University of Portsmouth and Royal Botanic Gardens, Kew Gardens — have developed a guide for agriculture in the face of climate change. If it has an overriding theme, it's that it's time to reintegrate wild variants of plants back into the genetic mix to strengthen crops' survivability.
The research is published in the Botanical Journal of the Linnean Society.
The problem with domestication
Credit: Markus Spiske/Unsplash
"When plants were domesticated," says Dr. Perez-Barrales, one of the study's authors, "they were artificially selected for a specific desirable trait. Artificial selection and farming have led to quality improvements in foods such as meat, milk, and fruit. However, over hundreds of years, there has been a negative impact to this process — a reduction in plant genetic diversity."
This lack of diversity could spell doom for crops as the conditions in which they grow are impacted by climate change. Scientists believe that a plant's natural genetic makeup, which evolved in response to its surrounding conditions, makes it more likely to be able to continue to adapt. Domesticated crops may lack such flexibility.
According to Dr. Perez-Barrales, "Climate change is altering the way crops behave." Unfortunately, she adds, "Crops have lost so much genetic diversity they are less able to adapt and respond to climate change. Scientists are now looking at wild crop relatives to see what traits can be improved to make crops better adapted to the current environmental challenges."
This revisiting of crops' ancestors is very much on the mind of the new study's authors.
A break from past practices
Credit: ittipon/Shutterstock/Big Think
The researchers began with a re-visiting of guidelines published in 1971 to see how they might be modified. Says Perez-Barrales, "The classification developed in the early 1970s needed to be updated, and in effect rebooted, to integrate this modern information."
The study's lead author Juan Viruel of Kew Garden explains, "With this information we can better select the wild species to improve our crops. It is an invaluable checklist for plant breeders and will help production of crops in a more sustainable way."
Those earlier guidelines also endorse the use of pesticides, now understood to harm fauna and leave fields toxic. The new study suggests a more benign, forward-looking way to deal with pests, says Perez-Barrales: "An alternative for plant breeders is to use wild crop relatives and use the natural genetic variation in those species that protects them against the natural enemies."
An example: linseed
To explain the type of guidance offered in the new study, Perez-Barrales offers linseed as a case in point:
"Some crops have just a few closely related species, whilst others might have a hundred or so," she says. "For example, linseed has more than 150 related species, and the challenge is how do we select the relevant traits and from what wild relatives? In answering this question, we realized that we needed to learn more from the biology of the species, which can only be done by using modern classification developed using the latest science."
"There may be a demand to grow linseed, for example, in countries at different latitudes. Linseed (Linum usitatissimum) was domesticated in the Middle East 10,000 years ago, and we can grow it in England because it naturally captured genes from pale blue flax, Linum bienne, allowing the crop to grow in northern and colder environments. My research looks at the natural variation in flowering of wild Linum species to see if we can use it to improve linseed. That way the right genes can be selected and introduced into the crop, something that plant breeders do regularly. These new guidelines will help plant breeders become more sustainable and efficient. We believe it is the future of farming."
Declining bee populations could lead to increased food insecurity and economic losses in the billions.
Bees have endured a disastrous half-century. In the winter of 2018, U.S. beekeepers reported losing 37.7 percent of their honeybee colonies. It was the largest die-off reported since the Bee Informed Partnership began its survey in 2006, yet in that decade, average winter losses of managed colonies were 28.7 percent. That's near twice the historic rate and part of a 50-year trend of declining species richness in wild bees and other pollinators.
That's bad news for the bees and also anyone who depends on the food generated through their labor. That is, all of us. According to the USDA, approximately 35 percent of the world's food crops depend on animal pollinators to reproduce, with some scientists estimating that "one out of every three bites of food we eat exists because of animal pollinators."
That many crops depend on pollination to reproduce is well-established; however, how much pollination proves a limiting factor to crop yield is less understood. If wild bee and managed honeybee populations continue to decline, will the amount of food available to feed us decline, too? That's the question a Rutgers-led team of researchers sought to answer.
From bee to farm to table
A bar graph showing the percentage of pollination limitation for the seven crops studied.
The research team selected seven crops to study: apples, almonds, pumpkins, watermelons, sweet cherries, tart cherries, and highbush blueberries. These were chosen because each is highly dependent on insect pollination for reproduction. The researchers then established a nationwide study across 131 U.S. and British Columbia farms. They selected only commercial farms in top-producing states—for example, Michigan and Oregon farms for blueberries. This way, their sample would represent the conditions and farming practices in which a majority of these crops are grown.
After collecting data on pollinator visitation rates and crop production, the researchers measured the data through three statistical models. They also analyzed the contribution differences between wild bees and managed honeybees as well as the economic value of the bees' service.
"We found that many crops are pollination-limited, meaning crop production would be higher if crop flowers received more pollination. We also found that honey bees and wild bees provided similar amounts of pollination overall," Rachael Winfree, a professor in the Department of Ecology, Evolution, and Natural Resources at Rutgers University-New Brunswick and the study's senior author, said in a release. "Managing habitat for native bee species [and] stocking more honey bees would boost pollination levels and could increase crop production."
Of the crops studied, apples, blueberries, sweet cherries, and tart cherries were hit hardest when pollination decreased. Watermelon and pumpkin yields weren't as limited by pollinators, possibly because these crops sport fewer blooms and flower in summer when the weather is less inclement. Almonds proved the outlier as the crop is the earliest bloomer yet not pollination limited. The researchers speculate that this is due to the almond industry's intense reliance on managed honeybees.
"Our findings show that pollinator declines could translate directly into decreased yields or production for most of the crops studied, and that wild species contribute substantially to pollination of most study crops in major crop-producing regions," the researchers write.
For the seven crops studied, the researchers estimate the annual production value of pollinators to be more than $1.5 billion. They also found that wild bee species provided comparable pollination, even for crops in agriculturally intensive regions.
Their findings were published in the most recent Proceedings of the Royal Society B: Biological Sciences.
Ecological and edible incentives
A protester shows a handful of bees that died by pesticides. The protest was held during the Bayer AG shareholder meeting in 2019.
(PhooMaja Hitiji/Getty Images)
The concern extends beyond these seven. Crops such as coffee, avocados, lemons, limes, and oranges are also highly dependent on pollinators and may prove pollination limited. If declining bee populations are tied to such yields, it could mean barer supermarket shelves and increased prices. While that may only be an annoyance to some, to poor and vulnerable communities who already struggle to secure salubrious, affordable food, such a deficit would present another barrier to the vital micronutrients necessary for a healthy life and diet.
Unfortunately, the threats to bees are numerous. Parasites, agrochemicals, monoculture farming, and habitat degradation all play a role, and neither stressor works in isolation. Sublethal exposure to neonicotinoids, an insecticide, can cause impairments in bees, while monoculture farming serves up a monotonous and unhealthy floral buffet. Both impede bees' immune systems, rendering them vulnerable to parasites such as Varroa destructor, a mite that can transmit debilitating viruses as it feeds on bees' fat bodies. And all of these stressors will likely be inflamed by climate change in the years to come.
Some have proffered mechanical solutions, such as Japan's National Institute of Advanced Industrial Science and Technology where technicians are developing robotic bees. These micro-drones are covered in gelled horsehair and have successfully cross-pollinated Japanese lilies. Other experiments include pollen sprays. However, the large-scale viability of tech-centric solutions seems questionable. After all, wild bees currently perform their ecological services pro bono and are as effective as managed honeybees. Any technological solution implemented in their absence would add to the agricultural costs and likely increase prices anyway.
Ecological amelioration will be necessary. To combat habitat fragmentation and strengthen biodiversity, many cities are implementing green-way strategies. For example, the Dutch city of Utrecht has decked its bus stop roofs with plants and grasses to create bee and butterfly shelters, while other cities are looking to foster bee-friend roadsides. And government initiatives incentivize farmers and landowners to adopt bee-friendly management practices. These solutions aren't only a matter of ecological conservation but also food security and public health.