Tag Archives: plant

Climate warming is changing the US planting zones

The last iteration of the plant hardiness map. The redder the area, the less it is resistant to extreme cold spells. The map is based on the average annual minimum winter temperature, divided into 10-degree F zones. See a high-resolution version of the map here. Image credits: USDA.

As climate heating starts to take its toll more and more, it’s becoming increasingly clear that planting patterns are also affected by these changes — and many plants are struggling to adapt. They do this in several ways, but one of the more direct ways is by changing their range. Simply put, as the climate becomes hotter and hotter, plants “move” to the north in the US (conversely, south of the equator, they migrate southward).

The most important factor for plants is the coldest winter temperature — this is crucial for the plants’ survival. According to a USDA study, the average coldest temperatures of 1989-2018 are more than 3°F warmer for the average city compared to the 1951-1980 baseline. Temperatures have significantly increased at almost all of the 244 stations analyzed. A warming climate shifts the natural ranges of plants all around the country and farmers and gardeners need to consider the ‘new normal’, the USDA urges.

These findings are echoed by the Third National Climate Assessment, which summarizes the impacts of climate change on the United States.

“Landscapes and seascapes are changing rapidly, and species, including many iconic species, may disappear from regions where they have been prevalent or become extinct, altering some regions so much that their mix of plant and animal life will become almost unrecognizable,” the assessment reads.

“Timing of critical biological events, such as spring bud burst, emergence from overwintering, and the start of migrations, has shifted, leading to important impacts on species and habitats.”

This is important to consider not only for gardeners but also for urban and rural planners. North Carolina Arboretum Director George Briggs says that people need to be climate-literate and make better decisions in the face of a shifting climate.

The National Oceanic and Atmospheric Administration (NOAA) also creates interactive plant hardiness maps which paint a similar picture.

“There is telling evidence that climate change is affecting plant life around the world and here at Longwood,” says Paul Redman, Director of Longwood Gardens in Pennsylvania. “Sharing the important work of NOAA with our staff, guests, and community is integral to our mission and continues Longwood Gardens’ commitment to environmental stewardship.”

In the grand scheme of things, it is yet another reminder that climate heating affects us in many (and often indirect) ways. It is a problem unfolding now, and that we need to address as soon as possible.

You can find out your area’s plant hardiness zone or check out the distribution of planting zones in your states, check out the USDA service here.

International research team creates eco superglue out of cellulose and water

Researchers at the Aalto University, the University of Tokyo, Sichuan University, and the University of British Columbia have developed an eco-friendly, plant-based superglue.

The novel glue is based on plant-sourced cellulose, the same material that paper is made out of. This means that the glue, which “outperforms” its synthetic competition “by a great many measures” can be made from waste plant matter. Unlike superglue, however, the cellulose-based material is strongest in a preferred direction, making it similar to “Peel and Stick” adhesives, the team explains.

Veggie glue

“Reaching a deep understanding on how the cellulose nanoparticles, mixed with water, [forms] such an outstanding adhesive is a result of the work between myself, Dr. Tardy, Luiz Greca, Professor Hirotaka Ejima, Dr Joseph J. Richardson and Professor Junling Guo and it highlights the fantastic collaboration and integration of knowledge towards the development of an extremely appealing, low-cost and safe application,” says Aalto Professor Orlando Rojas, the study’s corresponding author.

The new glue is roughly 70 times stronger (i.e. harder to tear apart) on its principal plane of bond compared to the perpendicular of that plane. In other words, a single drop can hold up to 90kgs of weight or be easily removed with just one or two fingers depending on how you handle it. This level of strength is very surprising for a plant-based glue, the team adds.

It’s even more surprising considering how simple to make this material is. The team created the glue by simply mixing cheap, plant-sourced particles with water. Curing time depends on the evaporation of this water (the team’s current mixture dries in about 2 hours), so it can be sped up by exposing the glue to heat.

The team envisions their glue used in protecting fragile components in machines that can undergo sudden physical shock (such as microelectronics), to fix reusable structural or decorative elements, in packaging, and as a more eco-friendly alternative for general adhesive. The world overall is producing more cellulose than ever, the team explains, making it very cheap — a great time to make eco glue.

“The truly exciting aspect of this is that although our new adhesive can be sourced directly from residual biomass, such as that from the agro-industry or recycled paper,” explains Dr. Blaise Tardy, the paper’s first author.

“It outperforms currently available commercial synthetic products by a great many measures.”

The paper “Exploiting Supramolecular Interactions from Polymeric Colloids for Strong Anisotropic Adhesion between Solid Surfaces” has been published in the journal Advanced Materials.

Billion-year-old green algae is a relative of all plants on dry land

Researchers at Virginia Tech report finding what may be a relative of today’s land plants ancestors — tiny green algae in modern China.

The algae fossils seen under the microscope.
Image credits Shuhai Xiao, Qing Tang / Virginia Tech.

Scientists have recently discovered a new fossil species of green algae. These diminutive seaweeds belong to a species known as Proterocladus antiquus, and each individual measures 2 millimeters in length, making them around the size of a common flea. Currently, this represents the oldest species of green algae ever discovered.

The green chlorophyll inside their tissues strongly suggests that Proterocladus antiquus could be related to the oldest ancestors of all the plants currently dotting the Earth’s dry landmasses.

Plant, I am your father

“The entire biosphere is largely dependent on plants and algae for food and oxygen, yet land plants did not evolve until about 450 million years ago,” said Shuhai Xiao, co-lead author of the paper and a Professor at Virginia’s Department of Geosciences.

“Our study shows that green seaweeds evolved no later than 1 billion years ago, pushing back the record of green seaweeds by about 200 million years. What kind of seaweeds supplied food to the marine ecosystem?”

The microfossils were found in rocks recovered at a site near the city of Dalian, in the Liaoning Province of northern China, an area that used to be a shallow ocean. The discovery suggests that green seaweeds were an important player in global ecosystems long before plants took root on dry soil.

These tiny algae were first spotted by Qing Tang, a post-doctoral researcher at Virginia’s Department of Geosciences, using an electron microscope. He shared this with Xiao and the duo worked to improve the imagining of the algae, and to date and describe the species.

A digital reconstruction of the species in a shallow ocean environment.
Image credits Shuhai Xiao, Qing Tang / Virginia Tech.

There are three groups of seaweed, brown (Phaeophyceae), green (Chlorophyta), and red (Rhodophyta) algae, each containing thousands of species. Red algae, the most common group today, are known to have existed from as far back as 1.047 billion years ago. Shuhai explains that land plants are believed to have evolved from green algae which moved and adapted to life on dry land. However, Xiao adds that not everyone is in agreement with this hypothesis.

“Not everyone agrees with us; some scientists think that green plants started in rivers and lakes, and then conquered the ocean and land later,” he says.

Red algae do photosynthesize, but they use up a different part of the light spectrum than green plants (namely the color blue, which penetrates water more easily). However, red algae use the pigment phycoerythrin to absorb blue light — making them appear red. This points to green seaweeds as a more likely ancestor for today’s plants. Furthermore, the team reports that “a group of modern green seaweeds, known as siphonocladaleans, are particularly similar in shape and size to the fossils we found.”

Today, plants underpin complex life on the planet by providing food and oxygen (through photosynthesis) for all animals. However, around 2 billion years ago, the Earth had no green plants at all in oceans, Xiao said.

“[Proterocladus antiquus displays] multiple branches, upright growths, and specialized cells known as akinetes that are very common in this type of fossil,” he adds. “Taken together, these features strongly suggest that the fossil is a green seaweed with complex multicellularity that is circa 1 billion years old. These likely represent the earliest fossil of green seaweeds. In short, our study tells us that the ubiquitous green plants we see today can be traced back to at least 1 billion years.”

According to Xiao and Tang, the tiny seaweeds once lived in a shallow ocean, died, and then became “cooked” beneath a thick pile of sediment, preserving the organic shapes of the seaweeds as fossils. Many millions of years later, the sediment was then lifted up out of the ocean and became the dry land where the fossils were retrieved by Xiao and his team, which included scientists from Nanjing Institute of Geology and Paleontology in China.

The paper has been published in the journal Nature Ecology & Evolution.

How plants decide when to flower and when to grow

An ancestral plant could help researchers understand when and why plants start to blossom.

Depiction of liverworts from Ernst Hackel‘s Kunstformen der Natur, 1904.

It’s easy to think that flowers have been around forever, but they actually haven’t been around for that long — well, in geological time at least. Flowering plants have emerged some 130 million years ago, during a period called the Cretaceous; for comparison, sharks have been around for more than 3 times that period. However, although flowering plants appeared relatively late (the first land plants emerged more than 700 million years ago), they are the most diverse group of land plants.

The act of flowering (which is essentially producing the plant’s reproductive structure) is quite complicated though. The transition to flowering is one of the biggest changes that a plant makes during its lifecycle. The time needs to be right, the environmental conditions need to be right, and the plant needs to have sufficient resources to trigger the changes. Without the environmental cues that trigger changes in the plant’s hormones, without a cold period to trigger vernalization, plants just don’t flower.

In some cases, plants choose to invest the energy for flowering into growing bigger. It’s kind of like a fallback investment: you don’t get to reproduce, but you get bigger, you’ll presumably have access to more energy and nutrients, and you’ll reproduce more the next time.

But not only flowering plants have to make this decision. In order to assess when this happens, a team of researchers working in Japan studied liverwort, a descendant of the first plants to move out of the ancient oceans and onto land.

Liverwort grows all over the world. It looks a bit like moss and also prefers the shady and cool environments that moss thrives in. Liverwort and moss are part of a group called Bryophyta. They don’t produce flowers and instead reproduce through spores, but fundamentally, the decision they must make is the same — although there are major differences, reproduction is always “expensive” in the plant world.

Healthy female Marchantia polymorpha liverworts develop distinctive umbrella-shaped structures when they are ready to reproduce. Image by Caitlin Devor, University of Tokyo.

The reason why researchers studied liverwort is that it has a relatively simple genome structure, especially compared to the plants most commonly used in this sort of study, like tobacco and Arabidopsis. The entire genome of the liverwort species Marchantia polymorpha was also sequenced in 2017 which further aided this study.

“Liverworts have the maximum power with the least structure,” said Professor Yuichiro Watanabe from the University of Tokyo’s Department of Life Sciences, an expert in plant molecular biology.

The team looked at microRNA — small molecules which regulate the activity of other genes. They found over 100 types of this molecule, and 8 of them were almost identical to microRNA found in Arabidopsis (which is a flowering plant).

This is particularly interesting. Why would the same gene-regulating mechanisms be found in an ancestral plant like liverwort and also in a modern plant which evolved hundreds of millions of years later?

“So, why keep them? We want to know what those shared microRNAs are doing, and liverworts are now a convenient model for us to investigate,” said Watanabe.

They found that one of the common microRNAs was helping plants control the shift to the reproductive stage. To test that it was indeed responsible for this change, they engineered a modified version of this microRNA. This confirmed their theory, and what happened was pretty weird: these modified liverworts produced reproductive cells on their vegetative tissues, rather than exhibiting normal growth.

“This was amazing to us. Those liverworts skipped some part of the reproductive process and the body itself becomes the reproductive organ,” said Watanabe.

Liverworts normally sprout distinctive male (top row, left) and female (bottom row, left) structures when they reproduce. When researchers genetically modify the plants to lack microRNA156/529, the plants develop reproductive organs on their vegetative structures, which are called thalli. Normal thalli (center) are solid green with smooth edges. MicroRNA156/529 knockout male thalli (top right) are transparent at the edges and microRNA156/529 knockout female thalli (bottom right) develop irregular edges. Image credit: Tsuzuki et al., 2019.

Watanabe imagines that in the future, farmers could measure the amount of microRNA in crops to predict harvest times.

“We hope our results inspire others to develop new applications for plant reproduction,” said Watanabe.

Journal Reference: Tsuzuki et al., 2019, DOI: 10.1016/j.cub.2019.07.084.

Ancient plants reproduce in the UK as global warming increases

In what is being described as a sign of global warming, an exotic plant in the United Kingdom has produced male and female cones outdoors. This is believed to be the first time this phenomenon took place in 60 million years.

Credit: Flickr

Two plants of cycads, a primitive tree that used to dominate the planet 280 million years ago, have produced cones on the sheltered undercliffs of Ventnor Botanic Garden on the Isle of Wight.

Native to Japan, the species is usually only found indoors as an ornamental plant in Britain. Nevertheless, one of the garden’s plants has produced what is believed to be the first outdoor female cone on record in the UK.

“For the first time in 60m years in the UK we’ve got a male cone and a female cone at the same time,” said Chris Kidd, the curator of Ventnor Botanic Gardens. “It is a strong indicator of climate change being shown, not from empirical evidence from the scientists but by plants”.

Cycads used to live in what is now Britain millions of years ago in an era when the Earth’s climate had naturally high levels of carbon dioxide. Fossils of the plants were found in the Jurassic strata of rock stretching from the Isle of Wight to the Dorset coast.

Seven years ago a plant growing outside at Ventor had produced a male cone. But now different plants have produced flower-like male and females cones, giving botanists the opportunity to transfer pollen and generate a fertilized seed.

Kidd argued that the recent summer’s heatwave and the record-breaking temperatures have caused the plant’s production of cones, with a run of milder winters also helping. Records kept at the botanic garden show that the highest average temperatures for January 100 years ago were lower than today’s lowest average for the same month.

 “It’s not something that’s happened with a short-term mild spell. It’s a longer-term warming which is making these things happen,” he said. “The plant will have made the decision to commit to cone production in summer 2018, and that production is set in place to run through over winter and produce the following year.”

Cycad species are composed of three families, the only surviving members of an ancient and largely extinct lineage that has changed little since the Jurassic period, and so are considered “living fossils”. All cycads are native to warmer parts of the world, but are naturally absent from Europe and Antarctica.

Mushroom.

Researchers identify gene that makes plants and fungi play nice — we’ll use it to make better crops

Researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL) are hacking the plant-fungi relationship to help us grow better, more productive, more resilient crops.

Mushroom.

Image credits Gustavo Torres.

The team has identified a specific gene that controls the symbiotic relationship between plants and fungi in the soil and used it to facilitate symbiosis in a plant species that typically resists such fungi. The research paves the way towards the development of food and bioenergy crops that can withstand harsh growing conditions, resist pathogens and pests, require less chemical fertilizer, and produce more plentiful per acre.

Magic ‘shrooms

“If we can understand the molecular mechanism that controls the relationship between plants and beneficial fungi, then we can start using this symbiosis to acquire specific conditions in plants such as resistance to drought, pathogens, improving nitrogen and nutrition uptake and more,” said ORNL molecular geneticist Jessy Labbe, the paper’s first author.

“The resulting plants would grow larger and need less water and fertilizer, for instance.”

The fungi Labbe refers to are known as mycorrhizal fungi (a mycorrhiza is a symbiotic association between a fungus and a plant), and they form a sheath around plant roots that benefits both participants. An estimated 80% of plant species have mycorrhizal fungi associated with their roots.

The plant receives water and raw minerals, particularly phosphorus, and ‘trades’ carbon-rich compounds in return. The fungal structure extends much farther than the plant host’s roots, allowing it to tap into a larger volume of soils. There is also some evidence suggesting these fungi also communicate with neighboring plants to limit the spread of pathogens and pests.Their relationship is so close that these fungal helpers may have been what allowed the ancient colonization of land by plants.

Given the importance of this partnership, biologists have been really eager to find the genetic mechanisms which underpin it. The current discovery is the culmination of 10 years of research at the ORNL and partner institutions that focused on producing better bioenergy feedstock crops such as the poplar tree (Populus).

Together with improvements in genomic sequencing, quantitative genetics, and high-performance computing over the last decades, the team drew on the ORNL data to narrow down the search to a particular receptor protein, PtLecRLK1. Once they had identified the likely candidate gene, the researchers took to the lab to validate their findings. Lab testing later confirmed that they were onto the right gene.

The researchers chose Arabidopsis, a plant known to treat the mycorrhizal fungus L. bicolor as a threat for the experiments. They engineered a version of this plant to expresses the PtLecRLK1 protein and then inoculated the plants with L. bicolor. The fungus completely enveloped the plant’s root tips, they report, forming a fungal sheath indicative of symbiote formation.

“We showed that we can convert a non-host into a host of this symbiont,” said ORNL quantitative geneticist Wellington Muchero, a co-author of the paper. “If we can make Arabidopsis interact with this fungus, then we believe we can make other biofuel crops like switchgrass, or food crops like corn also interact and confer the exact same benefits. It opens up all sorts of opportunities in diverse plant systems. Surprisingly, one gene is all you need.”

Jerry Tuskan, the director of the DOE’s Center for Bioenergy Innovation (CBI), which supported this research, calls the results “remarkable”, saying it paves the way towards new bioenergy crops that can thrive “on marginal, non-agricultural lands.”

“We could target as much as 20-40 million acres of marginal land with hardy bioenergy crops that need less water, boosting the prospects for successful rural, biobased economies supplying sustainable alternatives for gasoline and industrial feedstocks,” he concludes.

The paper “Mediation of plant–mycorrhizal interaction by a lectin receptor-like kinase” has been published in the journal Nature Plants.

Roots.

Research is getting to the root of climate change with bigger, deeper plant roots

New research is trying to give plants stronger, deeper roots to make them scrub more CO2 out of the atmosphere.

Roots.

Image via Pixabay.

Researchers at the Salk Institute are investigating the molecular mechanisms that govern root growth pattern in plants. Their research aims to patch a big hole in our knowledge — while we understand how plant roots develop, we still have no idea which biochemical mechanisms guide the process and how. The team, however, reports to finding a gene that determines whether roots grow deep or shallow in the soil and plans to use it to mitigate climate warming.

Deep roots are not reached by the scorch

“We are incredibly excited about this first discovery on the road to realizing the goals of the Harnessing Plants Initiative,” says Associate Professor Wolfgang Busch, senior author on the paper and a member of Salk’s Plant Molecular and Cellular Biology Laboratory and its Integrative Biology Laboratory.

“Reducing atmospheric CO2 levels is one of the great challenges of our time, and it is personally very meaningful to me to be working toward a solution.”

The study came about as part of Salk’s Harnessing Plants Initiative, which aims to grow plants with deeper and more robust roots. These roots, they hope, will store increased amounts of carbon underground for longer periods of time while helping to meaningfully reduce CO2 in the atmosphere.

The researchers used thale cress (Arabidopsis thaliana) as a model plant, working to identify the genes (and gene variants) that regulate auxin. Auxin is a key plant hormone that has been linked to nearly every aspect of plant growth, but its exact effect on the growth patterns of root systems remained unclear. That’s exactly what the team wanted to find out.

“In order to better view the root growth, I developed and optimized a novel method for studying plant root systems in soil,” says first author Takehiko Ogura, a postdoctoral fellow in the Busch lab. “The roots of A. thaliana are incredibly small so they are not easily visible, but by slicing the plant in half we could better observe and measure the root distributions in the soil.”

One gene called EXOCYST70A3, the team reports, seems to be directly responsible for the development of root system architecture. EXOCYST70A3, they explain, controls the plant’s auxin pathways but doesn’t interfere with other pathways because it acts on a protein PIN4, which mediates the transport of auxin. When the team chemically altered the EXOCYST70A3 gene, the plant’s root system shifted orientation and grew deeper into the soil.

“Biological systems are incredibly complex, so it can be difficult to connect plants’ molecular mechanisms to an environmental response,” says Ogura. “By linking how this gene influences root behavior, we have revealed an important step in how plants adapt to changing environments through the auxin pathway.”

“We hope to use this knowledge of the auxin pathway as a way to uncover more components that are related to these genes and their effect on root system architecture,” adds Busch. “This will help us create better, more adaptable crop plants, such as soybean and corn, that farmers can grow to produce more food for a growing world population.”

In addition to helping plants scrub CO2 out of the atmosphere, the team hopes that these findings can help other researchers understand how plants adapt to differences between seasons, such as various levels of rainfall. This could also point to new ways to tailor plants to better suit today’s warming, changing climate.

The paper “Root System Depth in Arabidopsis Is Shaped by EXOCYST70A3 via the Dynamic Modulation of Auxin Transport” has been published in the journal Cell.

Wax, water, and heat: how leaves survive in extremely hot environments

For plants, breathing is a balancing act between gathering what they need from the atmosphere and not losing too much water. A new study shows how some plants are able to regulate this mechanism and stay hydrated, even at very high temperatures.

The wax can make the surface of some leaves waterproof. Image credits: Rei.

In the 1950s, the German botanist Otto Ludwig Lange was studying plants in Mauritania — a country in western Africa that’s mostly covered by a desert. Lange noticed that leaves can heat up to temperatures as high as 56 degrees Celsius (133 Fahrenheit). He couldn’t figure out how they do it — how do plants get so hot without losing all their water?

In an attempt to solve that, botanists Markus Riederer and Amauri Bueno from Julius-Maximilians-Universität Würzburg in Germany, succeeded in revealing the secret studied the complex structure of a plant leaf.

Leaves are covered with a “skin” called a cuticle. The cuticle consists of lipids and polymers impregnated with tax, and it acts coherent outer covering of the plant. If you’ve ever seen droplets of water sitting on top of a leaf, it’s the wax-rich cuticle holding it in place.

This protective layer contains numerous pores (called stomata), which open and close according to the plant’s needs. The problem is that when these pores open up to allow the plant to breathe, they also allow water to evaporate. For desert plants, this is particularly troubling, but as Riederer and Bueno found, they have different ways of dealing with this.

Date palms have an innovative strategy to survive extreme heat.

For instance, a plant called a colocynth (Citrullus colocynthis), also called a bitter apple or a bitter cucumber opens up its pores when the heat gets going. This allows some of its water to evaporate as sweat, cooling down the leaves. This process is water-intensive, but the colocynth can afford it because it has a deep root which allows it to gather sufficient water. Decades ago, Otto Ludwig Lange noted that the plant can keep its leaves up to 15 degrees cooler than the surrounding air, and now the mechanism is better understood. However, the date palms have a radically different approach.

The date trees can’t afford to lose water, so they don’t “sweat”. As a result, their leaves get much hotter than the surrounding desert — up to 15 degrees hotter. The secret to its survival lies in the cuticle, specifically in the wax in the cuticle.

Unlike that of the colocynth and most other plants, the wax in the date palm’s skin is much more water-proof, due to its different water composition. While it’s not clear exactly what causes this different composition, the results are important because they could be used in agriculture, encouraging crop growers to select plants with certain cuticle waxes because they have better chance of survival in hot locations.

The study was published in the Journal of Experimental Botany.

Salamander.

Researchers find salamander-eating plants in Canadian provincial park

In a probable first for North America, researchers at the University of Guelph (U of G), Canada, have discovered meat-eating pitcher plants that dine on young salamanders, not just insects.

Salamander.

Recently metamorphosed spotted salamanders trapped inside the leaves of northern pitcher plants.
Image credits Patrick D. Moldowan et al., (2019),

The bogs in Ontario’s Algonquin Park are rife with deadly plants — if you’re a baby salamander. A new study led by U of G biologist Alex Smith reports on the “unexpected and fascinating case of plants eating vertebrates in our backyard, in Algonquin Park.” The findings, the team explains, may be unique to North America so far.

How the tables have turned

Pitcher plants are well-known for eating animals — but they tend to limit themselves to insects and spiders. This smaller prey is lured into the plants’ bell-shaped leaves, where they are digested in a mixture of rainwater and enzymes. However, until now, nobody had seen these plants capture anything larger. The team found evidence of northern pitcher plants (Sarracenia purpurea purpurea L.) capturing young spotted salamanders (Ambystoma maculatum Shaw) in Canada’s oldest provincial park, Algonquin Park.

The findings are even more surprising, considering that Algonquin is a very popular destination and has been a subject of scientific observations for hundreds of years. Noting how long the park has held this secret — despite generations of visiting naturalists, its proximity to major cities and a highway running through its southern end — Smith said, “Algonquin Park is so important to so many people in Canada. Yet within the Highway 60 corridor, we’ve just had a first.”

The study was borne from a discovery made by then-undergraduate student Teskey Baldwin in 2017 during a U of G field ecology course in the provincial park: he found a salamander inside a pitcher plant. Baldwin is a co-author of the current study. When they returned to monitor pitcher plants in a single pond in the park in the fall of 2018, the team found that roughly 20% of the plants had juvenile salamanders in their pitchers, each about as long as a human finger. Several plants they looked at had more than one captured salamander.

Smith explains that the ponds in this particular bog don’t house fish, making the salamanders a key predator and prey species in the local food webs. The observations also coincided with “pulses” of young salamanders moving onto land after changing from their (aquatic) larval stage. Smith believes that the animals were either lured by insects inside the plants’ pitchers, or they may have entered them in a bid to escape predators.

Some of the trapped salamanders likely died within three days, while others may have lived up to 19 days, the team explains. After expiring, they were broken down by digestive enzymes and other organisms in the water held inside the leaf. Smith said other factors may kill salamanders in pitcher plants, including heat, starvation, or pathogens.

Doesn’t sound like a particularly pleasant fate for the salamanders — so why do the plants put them through all that? Smith says that soil in the bog is relatively nutrient-poor, especially in regards to nitrogen (which is the hard-cap on how much plants can develop in natural environments). Other flesh-eating plants also grow in nutrient-poor environments, he notes, citing sundews and the Venus flytrap.

The only other species of meat-eating pitcher plant (native to Asia) consumes mostly insects and spiders, and occasionally small birds and mice. Smith said the Algonquin Park discovery opens new questions for biologists: are the salamanders a key prey species of the plants? Are the pitcher plants the main predators of these amphibians? And do the two species compete for insects — in which case, might the salamanders outcompete the plants?

“I hope and imagine that one day the bog’s interpretive pamphlet for the general public will say, ‘Stay on the boardwalk and watch your children. Here be plants that eat vertebrates,”‘ Smith quips.

The paper “Salamanders as rich prey for carnivorous plants in a nutrient‐poor northern bog ecosystem” has been published in the journal Ecology.

New mathematical model describes the growth pattern of plant leaves

Japanese researchers have described one of nature’s most ubiquitous patterns: a model which accurately describes how leaves grow on plants.

“We developed the new model to explain one peculiar leaf arrangement pattern. But in fact, it more accurately reflects not only the nature of one specific plant, but the range of diversity of almost all leaf arrangement patterns observed in nature,” said Associate Professor Munetaka Sugiyama from the University of Tokyo’s Koishikawa Botanical Garden.

Plant leaves have fascinated mankind since time immemorial. Some, like the sunflower, grow in a remarkably ordered geometry. Others seem to be much more chaotic, not subject to any apparent rule. There’s even a special name to describe the growth pattern of leaves on a plant: phyllotaxis.

Understandably, mathematicians have also been fascinated with these patterns. Leonardo da Vinci made observations of the spiral arrangements of plants, although he did not leave behind too many comments. Later on, naturalists noted that the spiral phyllotaxis of plants was sometimes clockwise and otherwise anti-clockwise, but it seemed to follow the so-called mathematical golden ratio.

It became clear that many plants follow a mathematical distribution, but no one was able to find a universal law to describe leaf growth.

In 1996, though, researchers got really close. Douady and Couder developed an algorithm that could account for many, but not all leaf arrangement patterns. This became known as the DC2 equation, and to this day, it is used to infer different variables of plant physiology.

Now, Japanese researchers believe they have found an even better rule, which can account for all the patterns in plants.

Unruly exceptions

They started out from a group of plants called “orixate”, from the species Orixa japonica, a shrub native to Japan, China, and the Korean peninsula. Orixate plants are part of an unruly group that doesn’t obey the DC2 equation. The angles between O. Japonica leaves are 180 degrees, 90 degrees, 180 degrees, 270 degrees, and then the next leaf resets the pattern to 180 degrees.

Leaves on an O. japonica branch (upper left) and a schematic diagram of orixate phyllotaxis (right). The orixate pattern displays a peculiar four-cycle change of the angle between leaves (180 degrees to 90 degrees to 180 degrees to 270 degrees). A scanning electron microscope image (center and bottom left) shows the winter bud of Orixa japonica, where leaves first begin to grow. Primordial leaves are labeled sequentially with the oldest leaf as P8 and the youngest leaf as P1. Image credits: Takaaki Yonekura, Akitoshi Iwamoto, and Munetaka Sugiyama.

At least four other unrelated plants groups follow a similar pattern. Sugiyama and colleagues wanted to see if they could find another equation to describe these plants, starting from the fundamental genetic and cellular machinery shared by all plants. The reason they took this approach is that if four separate groups all evolved this pattern, then it seems likely that there’s an underlying reason for it. Having it randomly pop up 4 times is just too unlikely.

They started from the two main shortcomings of the DC2 equation:

  1. No matter what parameters you put into it, some leaf arrangements are just not accounted for.
  2. The Fibonacci spiral leaf arrangement pattern is the most common spiral pattern observed in nature but is only modestly more common than other spiral patterns calculated by the DC2 equation.

To address these, the team focused on one key assumption of the equation: that leaves emit a constant signal to inhibit the growth of other nearby leaves. This makes sense because the plant would want some balance, and there is some research suggesting that this signal is propagated through a hormone called auxin, although the exact mechanism is not yet clear.

Sugiyama did away with the assumption that this signal was constant.

“We changed this one fundamental assumption – inhibitory power is not constant, but in fact changes with age. We tested both increasing and decreasing inhibitory power with greater age and saw that the peculiar orixate pattern was calculated when older leaves had a stronger inhibitory effect,” said Sugiyama. In other words, the older a leaf is, the less likely it is for new leaves to grow in its direct vicinity.

The resulting equation was not only capable of explaining the growth pattern of orixate plants but fit much better with the pattern observed in all plants, researchers claim.

“Our research has the potential to truly understand beautiful patterns in nature,” said Sugiyama.

The most common leaf arrangement patterns are distichous (regular 180 degrees, bamboo), Fibonacci spiral (regular 137.5 degrees, the succulent Graptopetalum paraguayense), decussate (regular 90 degrees, the herb basil), and tricussate (regular 60 degrees, Nerium oleander sometimes known as dogbane). Image credits: Takaaki Yonekura, Akitoshi Iwamoto, and Munetaka Sugiyama.

However, there are still some shortcomings with this model — while it did account for most of the exceptions, it didn’t account for all the exceptions.

“There are other very unusual leaf arrangement patterns that are still not explained by our new formula. We are now trying to design a new concept that can explain all known patterns of leaf arrangement, not just almost all patterns,” said Sugiyama.

It remains to be seen if biologists or other researchers working with this equation will confirm its results and incorporate it into their work. For now, the relationship between mathematics and botany seems to have gotten even deeper.

Journal Reference: Takaaki Yonekura, Akitoshi Iwamoto, Hironori Fujita, Munetaka Sugiyama. 2019. Mathematical model studies of the comprehensive generation of major and minor phyllotactic patterns in plants with a predominant focus on orixate phyllotaxis. PLOS Computational Biology. DOI: 10.1371/journal.pcbi.1007044.

A new technique uses nanoparticles to deliver genes into the chloroplasts of plant cells, works with many different plant species. Credit: MIT.

Nanoparticles inject genes directly into the chloroplast of plants

A new technique uses nanoparticles to deliver genes into the chloroplasts of plant cells, works with many different plant species. Credit: MIT.

A new technique uses nanoparticles to deliver genes into the chloroplasts of plant cells, works with many different plant species. Credit: MIT.

Researchers at MIT sprayed tiny nanoparticles containing foreign genes into the chloroplasts of plant cells. The novel technique is an easier and less risky way to genetically modify plants, in contrast to established gene tools which can be expensive and cumbersome.

DNA delivery straight to the plant’s cell

The researchers, led by Michael Strano, who is a professor of chemical engineering at MIT, first learned that they could penetrate plant cell membranes with nanoparticles a few years ago. At the time, they found that if the size and electrical charge of the nanoparticles were just right — and every plant is different — they could then penetrate the plant cell’s membrane through a mechanism called lipid exchange envelope penetration (LEEP).

Previously, Strano and colleagues used this method to make plants grow by embedding luciferase, a light-emitting protein, into the leaves of a plant. But could genes be implanted in the same way? That’s what the research team set out to discover in their latest study published in Nature Nanotechnology.

“Bringing genetic tools to different parts of the plant is something that plant biologists are very interested in,” Strano says. “Every time I give a talk to a plant biology community, they ask if you could use this technique to deliver genes to the chloroplast.”

Chloroplasts are small organelles inside the cells of plants and algae, where sugar is made for fuel through photosynthesis. These tiny organelles contain about 80 genes, which code for proteins involved in photosynthesis.

Scientists had previously manipulated genes inside chloroplasts using a high-pressure technique called “gene gun”, however, this can result in damage to the plant and is not very effective.

First, the MIT researchers created nanoparticles consisting of carbon nanotubes wrapped in chitosan, which a naturally occurring sugar. They then added DNA whose negative charge allows it to easily bind to the positively charged nanotubes. The nanoparticle solution is then simply sprayed with a needleless syringe onto leaves, penetrating them through tiny pores called stomata, which typically regulate water evaporation.

The nanoparticles pass through the cell’s wall, membrane, ultimately penetrating the double membranes of the chloroplasts. Once inside, the slightly less acidic environment of the chloroplast causes the DNA to disentangle from the nanoparticles, which is now free to produce proteins.

As a demonstration, researchers used this technique to deliver a gene that codes for a yellow fluorescent protein in order to easily visualize the effectiveness of the process. They found that 47% of plant cells glowed in yellow, showing that the DNA producing the protein had been successfully delivered to the chloroplast. Researchers employed a variety of plants, including spinach, watercress, tobacco, arugula, and Arabidopsis thaliana. Virtually any kind of plant, including food crops, can be used. What’s more, different kinds of nanomaterials other than carbon nanotubes ought to work to produce similar results.

“This is a universal mechanism that works across plant species,” Strano said.

The technique could prove useful in engineering crops and vegetables with useful traits, such as drought and fungal resistance. And because the genes are carried only in the chloroplasts, they are only passed to offspring and not other plant species.

“That’s a big advantage, because if the pollen has a genetic modification, it can spread to weeds and you can make weeds that are resistant to herbicides and pesticides. Because the chloroplast is passed on maternally, it’s not passed through the pollen and there’s a higher level of gene containment,” Tedrick Thomas Salim Lew,  MIT graduate student and co-author of the study, said.

Close-up of cotton sprouts under a protective cover aboard a Chinese moon lander. Credit: CLEP.

China grows the first plants on the far side of the moon

Close-up of cotton sprouts under a protective cover aboard a Chinese moon lander. Credit: CLEP.

Close-up of cotton sprouts under a protective cover aboard a Chinese moon lander. Credit: CLEP.

At the dawn of the new year, China landed the Chang’e 4 probe on the far side of the moon– also known as the dark side of the moon. Among its various scientific missions, Chang’e 4 was tasked with growing cotton, potato, yeast, and fruit flies. Now, state media channels announced that the first cotton seeds have sprouted. This the first time that a plant has started growing on the moon, opening up new and exciting possibilities. Previously, plants had only been grown in microgravity aboard the International Space Station.

The plants were not grown in lunar soil but rather in contained, self-sustaining mini-biospheres. Each type of plant or organism arrived on the moon inside its own container, where monitoring sensors control water, temperature, pressure, humidity, nutrients, and ensure a microclimate similar to conditions found on Earth. The biggest challenge is controlling temperature, which on the lunar surface can fluctuate between -173°C and 100°C. Case in point, the cotton sprout died after nine days of growth during a freezing night on Sunday, when temperatures dropped to -150°C, overwhelming the heaters. Theoretically, the only thing that should be different in super controlled environment is gravity — which on the moon is 16.6% that on Earth’s surface.

“Chang’e-4 is humanity’s first probe to land on and explore the far side of the moon,” said the mission’s chief commander He Rongwei of CASTC. “This mission is also the most meaningful deep space exploration research project in the world in 2018,” He said, according to state-run Global Times.

The whole experiment is contained within a canister measuring just 18cm in height and weighing 3kg.

Back on Earth, Chinese scientists have set up an identical control experiment, which is reportedly growing plants a lot faster than on the moon.

Some have expressed concerns that the Chinese experiment risks biologically contaminating the moon. That may well be the case but there are have been numerous missions which performed controlled or crashed landing on the moon already since the 1960s, and they also carried possible contaminants.

The fact that plants seem to sprout normally on the moon is very good news for human space exploration efforts. The findings suggest that astronauts could grow their own food on the moon in controlled environments, thereby freeing up precious cargo space for supply missions from Earth. This is even more important when you picture the grander scheme of things, with the moon positioned as a staging post on our way to Mars. Previously, researchers found ice on the lunar surface which can be used to supply an outpost with water or fuel.

“We have given consideration to future survival in space. Learning about these plants’ growth in a low-gravity environment would allow us to lay the foundation for our future establishment of space base,” said Professor Liu Hanlong, the chief scientist behind this experiment.

Plant cyborg.

MIT designs and builds a plant-robot plantborg that can move towards light

An MIT Media Lab team build a plant-cyborg. Its name is Elowan, and it can move around.

Plant cyborg.

Image credits Harpreet Sareen, Elbert Tiao // MIT Media Labs.

For most people, the word ‘cyborg’ doesn’t bring images of plants to mind — but it does at MIT’s Media Lab. Researchers in Harpreet Sareen’s lab at MIT have combined a plant with electronics to allow it to move. The cyborg — Elowan — relies on the plant’s sensory abilities to detect light and an electric motor to follow it.

Our photosynthesizing overlords

Plants are actually really good at detecting light. Sunflowers are a great example: you can actually see them move to follow the sun on its heavenly trek. Prior research has shown that plants accomplish this through the use of several natural sensors and response systems — among others, they keep track of humidity, temperature levels, and the amount of water in the soil.

However, plant’s aren’t very good at moving to a different place even if their ‘sensor and response systems’ tell them conditions aren’t very great. The MIT team wanted to fix that. They planned to give one plant more autonomy by fitting its pot with wheels, an electric motor, and assorted electrical sensors.

The way the cyborg works is relatively simple. The sensors pick up on the electrical signals generated by the plant and generate commands for the motor and wheels based on them. The result is, in effect, a plant that can move closer to light sources. The researchers proved this by placing the cyborg between two table lamps and then turning them on or off. The plant moved itself, with no prodding, toward the light that was turned on.

While undeniably funny, the research is practical, too. Elowan could be modified in such a way as to allow it to move solar panels on a house’s roof to maximize their light exposure. Alternatively, additional sensors and controlling units would allow a similar cyborg to maintain optimal temperature and humidity levels in, say, an office. With this in mind, the team plans to continue their research, including more species of plants to draw on their unique evolutionary adaptations.

Plant roots may hold the key to the next generation drought-resistant crops

If we want to feed the world, we’d better pay attention to root architecture, not just the upper half of the plant, researchers warn.

A freesia’s root architecture helps the plant store food to survive seasonal weather conditions. Image credits: Brian Atkinson.

In the past decades, the developed world has been spoiled: not only do we have access to an essentially unlimited supply of food, but the variety and year-round diversity are also unprecedented. There’s also more food overall — the world produces 17% more food per person today than 30 years ago, even considering a significant population growth. But as the population continues to grow and climate change continues to take its toll, feeding the world might become more problematic.

Naturally, scientists are working on ways to improve crops and plant varieties, by tweaking their genes, the pesticide use, and even improving the surrounding soil. But if you ask a group of Nottingham researchers, they’ll likely tell you that the solution lies beneath the ground — in the plants’ roots.

‘You could argue that for the last 10,000 years, we have selected crop varieties on the basis of the upper half, and not focused on this hidden part of crops,’ said Malcolm Bennett, professor of plant science at the University of Nottingham, UK. ‘If we could select new crop varieties based on root architecture, we could significantly improve their ability to forage for water.’

The most visible effects of drought are seen in the overground components, particularly in leaves, but the hidden half is just as important — if not even more so. Roots provide anchorage to all plants, absorb water and nutrients from the soil and store food for the plant. When there’s not much water around, roots can grow deeper to suck water from further underground. If nutrients are sufficient towards the surface, shallow roots grow denser.

It’s easy to understand why roots are relatively understudied: they’re beneath ground, which makes them much more difficult to study. In order to overcome that, Bennett and colleagues used an X-ray micro-computed tomography (micro CT). It’s a technique commonly used in human medicine, but Bennett’s machine is a colossus — 3-4 times larger than a typical medical scanner, allowing them to image living roots in great detail.

Maize develops from a single kernel from which both the stem and earliest roots grow. The root system grows around a primary root supported by smaller lateral roots. As the plants grow older, aboveground brace roots sprout and become the main source of nutrients and water. Image credits: Brian Atkinson.

Because plants can withstand more X-ray radiation than humans, the resolution is also improved, allowing researchers to image even the thinnest of roots. Furthermore, scanning can be done repeatedly to monitor changes. In total, over 8,000 X-ray snaps were taken, with computer algorithms stitching them together to develop an incredibly detailed 3D image.

Among many other plants, the team used this approach to scan hundreds of varieties of wheat to see how they respond to stress. The results were surprising.

‘We noted something fascinating. Plants that were most efficient at using water changed the angle of their roots when you applied drought stress,’ said Prof. Bennett. ‘Steeper rooting angles allowed them to forage for deeper sources of water.’

Prof. Bennett also said that recently, they identified master genes that control root angle in maize and rice. This root angle is extremely important in water absorption, which in turn affects how plants manage dry spells.

‘To maintain wheat yields here (in the UK), we need to have new varieties with roots that grow an extra half metre at least,’ Prof. Bennett explained. Other parts of Europe are similarly concerned about water shortages and its effect on crops.

‘We could optimise crop root systems to take up nutrients more efficiently, such as selecting deeper rooting varieties to capture nitrogen as it moves deeper into soil,’ said Prof Bennett. ‘The idea of selecting new varieties based on root architecture is gaining support amongst breeding companies and researchers.’

Sugar beet grows around a main tap root which stores the sucrose harvested for sugar. The cells dyed green, as viewed under a microscope, form the cortex of the plant, where nutrients and sucrose are stored. Image credits: Brian Atkinson.

Dr. Christophe Maurel, plant scientist at the National Center for Scientific Research (CNRS), says that these findings could also be useful in the case of another very important crop: maize. Maize can be susceptible to drought in Europe because it flowers in summer, unlike wheat, which flowers earlier.

But there’s also a downside to having roots that suck up more water.

‘The more vessels at the root tips, the more susceptible they were to invasion by soil bacteria,’ Dr. Maurel said, meaning there is a trade-off between a better ability to withstand drought and vulnerability to infection.

Maurel also highlights that in a way, scientists are almost in an arms race with global warming — drawing conclusions is not something that can be done immediately, and it will be a while before results go from the lab and onto agricultural fields — but in the meantime, temperatures continue to rise.

 ‘We might help breeders not in five years, but maybe 10 to 20 years,’ he said. ‘Anyway, in 10 to 20 years we will be facing even stronger challenges with drought and climate change.’

Scientists show how plants communicate — and it looks amazing

Image credits: Simon Gilroy.

For a while now, researchers have been observing an intriguing phenomenon: when one part of a plant is under attack (say, by a hungry caterpillar), the defense systems are activated in other parts of the plant. But how do they know to do so? A new study sheds new light on that process, highlighting the impressive means through which plants communicate — and they have the amazing videos to go with it.

Plants don’t have nerves, but, as it turns out, they have something that’s surprisingly similar: a network of signaling cues, the same cues that many animals use in their own nervous systems.

“We know there’s this systemic signaling system, and if you wound in one place the rest of the plant triggers its defense responses. But we didn’t know what was behind this system,” explained botanist Simon Gilroy from the University of Wisconsin-Madison.

Gilroy and botanist Masatsugu Toyota, a former postdoc in Gilroy’s lab, wanted to see how this signal propagates.

“We do know that if you wound a leaf, you get an electrical charge, and you get a propagation that moves across the plant,” Gilroy adds. What triggered that electric charge, and how it moved throughout the plant, were unknown. But there was one likely culprit: calcium.

Calcium is found almost everywhere in cells, often acting in a sensor-like fashion. Because it carries an electrical charge, it can produce a signal about a changing environment. But the problem is that calcium is very difficult to study, spiking and dipping quickly, and researchers needed a way to study it in real time.

So they genetically engineered a mustard plant that would reveal changes in calcium concentration in real-time. The thus-developed plants produce a protein that fluoresces around calcium — basically, whenever there’s a spike in calcium, the plant lights up. They found that this allowed them to see the signaling process, which propagates at a speed of about 1 millimeter per second — lightning fast in the plant world, but still only a fraction of what we see in the animal world.

Toyota and Gilroy showed that when the plant is threatened (most commonly by insects) waves of calcium flow from the source of the attack throughout the plant. As soon as the defensive wave hits, defensive hormones are released in the plant in an attempt to stop the damage from taking place. These noxious hormones deter some of the plants’ predators from eating them.

The team also wanted to see what triggers this calcium release in the first place. Previous research had suggested that glutamate, an amino acid and significant neurotransmitter in both plants and animals, is the key. So they used mutant plants lacking glutamate receptors and found that the flow of calcium was also disrupted.

“Lo and behold, the mutants that knock out the electrical signaling completely knock out the calcium signaling as well,” says Gilroy.

So essentially, when the plant is bitten or attacked, it spills out glutamate from the wound site. From there, this triggers a wave of calcium flowing through the plant, which leads to activation of the plant’s hormonal defense mechanisms. It’s a remarkably complex and dynamic process, for a group of organisms which are often regarded as inert and lacking a nervous system.

In addition to the describing this process, the study videos can also help scientists visualize this astonishing mechanism — and let’s admit it, it’s also really nice to look at.

“Without the imaging and seeing it all play out in front of you, it never really got driven home — man, this stuff is fast!” he says.

The study has been published in the journal Science.

A flurry of new studies finds being a vegetarian is good for you

If you’re still not convinced that being a vegetarian is good for you — then this will probably change your mind.

In recent years, more and more studies are showing just how healthy being a vegetarian really is. In fact, it’s reached the point where many health organizations shortlist vegetarianism as one of the few go-to diets. Of course, things are not always straightforward, and eating only plant-based foods doesn’t guarantee that you’re healthy — but it’s certainly a step in the right direction. Now, a new series of studies adds even more weight to that idea.

Study 1: Vegetarianism lowers heart disease risk

Among its main advantages, the vegetarian diet is most praised for its cardiovascular benefits. It’s one of the diets that heart doctors often recommend.

The new study was carried out on nearly 6,000 people in the Netherlands, finding that those who ate more plant protein at the expense of animal-derived protein showed a lower risk of developing coronary heart disease. The study was carried out over 13 years, and results showed a very strong correlation.

The study confirms what others have already found, and solidifies the vegetarian diets as one of the go-to for reducing heart diseases.

Abstract

Study 2: Replacing animal protein with plant protein associated with less plaque in the arteries

It’s one of the main myths about being a vegetarian: you’re not getting enough protein. But not only is plant protein sufficient to live by, it’s actually better than animal protein for your body. A study of 4,500 Brazilian adults finds that people who regularly consumed more plant-based protein were nearly 60 percent less likely than those consuming more animal-based protein to show evidence of plaque in the heart’s arteries.

Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood and it can slowly build up and stiffen the arteries, with dangerous consequences.

Abstract

Study 3: Eating plant-based foods associated with less weight gain

Not all vegetarian foods are created equal — some are healthier than others.

Ah yes, the most popular concern about every diet: weight management. A study carried out over 4 years tracked the body weight among more than 125,000 adults. The study found that diets rich in healthy plants (whole-grains, fruits, vegetables, and nuts) were associated with less weight gain. However, unhealthy plant foods (such as sugars, refined grains, and fries) are associated with more weight gain.

Significantly, you don’t need to fully dedicate yourself to vegetarianism — the more healthy plant-based foods, the better, even if you don’t go all the way.

Abstract

Study 4: Vegetarian diet associated with reduced risk of heart disease and diabetes

I feel like a broken record already: a vegetarian diet reduces your risk of heart diseases — and diabetes. A study on South Asians living in the US found that vegetarians have a lower body mass index, smaller waist circumference and lower amounts of abdominal fat, lower cholesterol, and lower blood sugar compared to people in the same demographic group who ate meat.

This suggests that the vegetarian diet reduces the risk of heart disease in a number of ways, often interconnected.

Abstract

Study 5: Eating higher quality plant-based foods associated with lower risk of death

Results from this study are even blunter: if you want to live longer, eat more good plants. Analyzing data from 30,000 US adults, researchers found that the quality of plant-based foods in the diet is more important than the quality of animal-based foods. Opting for better plant-based components of the diet lowered mortality by 30 percent while higher quality animal-based components had little effect on mortality.

The effects were strongest on people with chronic health conditions.

Abstract

These are just a few of the studies which will be presented at flagship meeting of the American Society for Nutrition, called Nutrition 2018. Overall, the scientific evidence showing the keeps piling up, so if you want to stay healthy, focus more on those plants!

Plants use underground networks to see when their neighbors are stressed

Plants have developed surprisingly complex communication networks which allow them to communicate with each other about what’s happening on the surface.

Graphical illustration of above ground interactions between neighboring plants by light touch and their effect on below-ground communication. Image credits: Elhakeem et al.

Graphical illustration of above ground interactions between neighboring plants by light touch and their effect on below-ground communication. Image credits: Elhakeem et al.

Despite their immobile lifestyle, plants are actually more active than you’d think. Aside from all the biochemical reactions that enable them to go about their day-to-day lives, plants can also communicate complex messages underground. Essentially, these messages take the form of chemicals secreted by roots into the soil which are then detected through the roots of nearby plants.

These chemical “messages in a bottle” can tell plants whether their neighbors are relatives or strangers and help them direct their growth accordingly.

Touch is one of the most common stimuli in higher plants and is well known to induce strong changes over time. Recent studies have demonstrated that brief touching among neighboring plants can be used to detect potential competitors. As plants grow in close proximity to other plants, they constantly monitor any cues that happen above ground — but they do the same below ground as well.

To better understand how this happens, as well as to learn more about the ways above ground factors influence what happens below the surface, a team of scientists from the Swedish University of Agricultural Sciences “stressed” corn seedlings and then looked for growth changes in nearby plants. Essentially, they brushed the corn leaves to simulate the touch of a nearby plant leaf and then monitored what chemicals the plant root secreted. The team then took those chemicals and transferred them to other plants to see how they react. They found that plants exposed to the chemicals responded by directing their resources into growing more leaves and fewer roots than control plants.

Researchers write:

“Our study clearly shows that roots of very young maize seedlings pose an extraordinary capacity to quickly detect changes in cues vectored by growth solution directing roots away from neighbours exposed to brief mechano stimuli. In this way, roots may detect the changed physiological status of neighbours through the perception of cues they release, even if chemical analyzes did not show significant changes in metabolite composition.”

Basically, the team showed that what happens above ground influences what happens beneath the ground surface of a plant — and the way through which they communicate this is more complex than we thought. This makes a lot of sense since the ability of plants to rapidly detect and respond to changes in their surrounding environment is essential for determining their survival.

Lead author Velemir Ninkovic concludes:

“Our study demonstrated that changes induced by above ground mechanical contact between plants can affect below ground interactions, acting as cues in prediction of the future competitors.”

Journal Reference: Elhakeem A, Markovic D, Broberg A, Anten NPR, Ninkovic V (2018) Aboveground mechanical stimuli affect belowground plant-plant communication. PLoS ONE 13(5): e0195646. https://doi.org/10.1371/journal.pone.0195646

Indoor plants can be natural, sustainable air-cleaning systems

We think of plants mostly as things we use to decorate our homes, but a new study shows that they can play a very important role in cleaning out the air we breathe.

A semi-autonomous, sustainable, eco-friendly air cleaning system. Or as we usually call it — a plant.

People in industrialized countries spend more than 80% of their time indoors — that’s over 19 of the 24 hours in a day in air-tight buildings, without much exposure to the outside air. Buildings also tend to accumulate particulate matter and potentially toxic gases, and our indoor furniture, carpets, paints, and office equipment can be sources of these unwanted compounds. Many buildings spend a lot of energy and money for ventilation and air purification, but that service could also be provided for free — by plants.

Frederico Brilli, a plant physiologist at the National Research Council of Italy integrated a system which featured indoor plants and sensor-controlled air cleaning and monitoring technologies to see just how much of an effect plants really have.

We know surprisingly little about the effect indoor plants have on air quality. NASA carried out i pioneering work in the 1980s, but they relied on a simple experimental approach. You’d expect that with the advent of modern sensors and smart houses we’d have a trove of data, but we really don’t. We also care surprisingly little — plants are almost exclusively picked either for their aesthetic qualities, or for their ability to survive with very little maintenance. In other words, we want nice plants we don’t have to take care of.

“For most of us plants are just a decorative element, something aesthetic, but they are also something else,” says Brilli.

[Also Read: 7 Potted Plants that Will Remove Indoor Air Pollution from Your Home, Proven by Science]

Succulents, or water-retaining plants, such as this jelly bean plant (Sedum rubrotinctum), are often grown as houseplants. Image credits: JJ Harrison.

Brilli and his colleagues found that plants improve air quality through a variety of methods: they absorb carbon dioxide and release oxygen through photosynthesis, they absorb pollutants and store them in the soil-root system, and they also increase humidity in the room by transpiring water vapor through their pores. They also interact with microbiomes in ways that we don’t really understand — they favor the development of some microbial communities while discouraging others.

Previous studies have suggested that most plants have positive effects on microbiomes — they favor the development of microbial communities that are harmless or even helpful to humans (microbial communities can also remove pollutants). But we don’t really know how different plants behave. For instance, some plants can trigger allergies or lung inflammation. So while Brilli’s study offers some much-neededd information about the plants’ effect on air quality, much more research is needed if we want to thoroughly understand the big picture. According to Brilli, future studies could show how to “optimize the use of plants indoors, in terms of how many plants per square meter we need to reduce air pollution to a certain level.”

[Also Read: Why you should use potted plants to clean air pollutants from your home]

Of course, plants won’t replace ventilation or indoor heating or cooling, but they can complement these systems, making then more efficient and sustainable in the long run. A simple thing like a potted plant could have a great effect on our overall health, and we might not even realize it.

“The ability of plants to phytoremediate indoor air pollutants has been overlooked for too long,” the study concludes.

The study “Plants for Sustainable Improvement of Indoor Air Quality” by Brilli et al. has been published in the journal Trends in Plant Science.

Marijuana farm in Colorado. Credit: Pixabay.

Marijuana Scientists Are Getting High Wages

Marijuana farm in Colorado. Credit: Pixabay.

Marijuana farm in Colorado. Credit: Pixabay.

Marijuana has almost always been a controversial topic in public and in the scientific community as well. It makes headlines, and is, of course, the craving of many addicts. Many renowned authors have sampled the cannabis drug in the hopes of improving or embellishing their creative writings. Such writers include Alexander Dumas, Victor Hugo, Jack Kerouac, Carolyn Cassady, and William S. Burroughs.

The recreational use of the drug also assisted in feeding the Hippie Movement of the 1960’s and ’70’s. It has been the subject of much discussion, resulting in several publications dedicated solely to this purpose such as The High Times and Dope Magazine. However, marijuana does seem to have some healthful pros going for it when applied properly in certain circumstances. Among a number of benefits, it has been known to protect the brain following a stroke, to control some kinds of muscle attacks, and even to reduce the spread of cancerous cells.

The historical record places the date of one of the earliest medicinal uses of cannabis in the 2700’s BC in China. Emperor Shen Nung who reigned during that time wrote that it was employed to help with ailments such as rheumatism and malaria. In the 16th century AD, it was introduced in the Americas. Since then, practically anything having to do with weed makes headlines. In particular, current information relating to the legalities of the drug makes for hot news.

California, the Golden State, is the eighth state to make the recreational use of marijuana legal as of January 1, 2018. Now Hollywood stars (and all the others who want to) are free to openly smoke weed whenever they please. But medical marijuana is a different animal in the legal game because, as it has already been stated, it can improve or safeguard human health in some cases. Medical marijuana is currently legal to use in 29 of the 50 states.

A lot of “dough” can be made off of dope. Those in the business of growing and providing pot can definitely make a decent income from it. But many of the people doing this have found their banks will not allow their cannabis cash to be deposited. This is because marijuana is illegal under federal law. (The banks are operated by the federal government.) So I would not advise anyone to go down that type of career path. If pot fascinates you, there are other job opportunities which are growing more popular as they are in demand.

One such open career choice is for cannabis researchers, sometimes referred to as “weed scientists.” By the year 2020, it is predicted the marijuana science industry will be employing about 300,000 individuals. Simple tasks such as bud trimming can pay anywhere from $8 to $12 per hour. More experienced positions for marijuana scientists are comprised of tasks like teaching, conducting research, and even formulating regiments for biological control agents. In order to go into this profession, one has to have a valid interest in topics like weed science (duh), soil science, and agriculture. An aspiring weed scientist will require a BS degree in an area such as agronomy, horticulture, or soil science. The specific type of education required will depend on the kind of work one wants to go into.

glowing-plants

Glowing plants imbued with firefly enzymes might one day replace lamps

glowing-plants

Credit: Melanie Gonick/MIT.

Your bedpost plants might one day double as a reading lamp if MIT’s latest proect ever takes off. The team, which specializes in nanobionics, embedded nanoparticles into the watercress plant (Nasturtium officinale) to make it glow in a dim light. MIT hopes that this proof of concept one day makes its way into our homes and even replaces street lighting with glowing trees.

“The vision is to make a plant that will function as a desk lamp — a lamp that you don’t have to plug in,” said Michael Strano, Professor of Chemical Engineering at MIT and senior author of the study, in a statement. “The light is ultimately powered by the energy metabolism of the plant itself.”

To make plants glow, MIT engineers turned to luciferase — the oxidative enzymes that produce bioluminescence lending glowing abilities to animals like fireflies or certain mushroom species. Luciferase catalyzes a compound called luciferin which is what generates the light. Another molecule called co-enzyme A removes reaction byproducts that inhibit luciferase activity.

Previously, Vanderbilt University scientists employed a modified version of luciferase to make brain cells glow in the dark. 

All of these three components were packaged into carriers that balance light and toxicity, submerged in a solution, then exposed to high pressure to force the particles into the stomata pores of leaves. This way, watercress plants were able to expel a dim light for almost four hours before the compounds wore off, as reported in the journal Nano Letters.

Next, the team plans on refining its technique to make plants glow for a longer time. The firefly-compounds could potentially be incorporated in a spray so that basically any plant can be coaxed to emit light. So far, MIT demonstrated the luciferase compounds in plants like watercress, arugula, kale, and spinach.

Such technology could one day prove as a useful alternative to conventional products for low-intensity indoor lighting. In some places, streets lamps could be replaced by glowing trees, for instance, thus reducing our energy consumption and carbon footprint.

“Plants can self-repair, they have their own energy, and they are already adapted to the outdoor environment,” Strano says. “We think this is an idea whose time has come. It’s a perfect problem for plant nanobionics.”