Global plant evolution may have been due to efficient roots
A team of researchers from Princeton University and the Chinese Academy of Sciences (CAS) has developed a new theory of plant evolution. The experts propose that plants adapted their roots underground as they evolved to make themselves more efficient and independent.
As plant species spread north and south from the Tropics over the last 400 million years, they moved into regions with less nutrient-rich soils. According to the researchers, the plants began narrowing the tips of their roots and spreading them out to explore the soil for nourishment.
“These are the secret strategies that plants have used over time to take over the world,” said study co-author Lars Hedin. “Our goal was to unlock the understanding of those strategies, and our findings offer a new global theory for plant evolution. Hidden underground there has been a tremendous game of survival-of-the-fittest and we are fortunate to have the first-ever view of the science of that game.”
Hedin said that the study provides new insight into how plants adapt to new environments. He pointed out that past studies have been mainly focused on above-ground characteristics of plants.
“Thus far, everybody has quite naturally tried to understand how plants are organized by looking at above-ground traits,” said Hedin. “But our findings do not follow the above -ground theories – that was a surprise.”
For two years, the researcher team examined a uniquely large database of root traits consisting of 369 species from seven different biomes including: desert, grassland, Mediterranean, boreal, temperate, subtropical and tropical.
The study revealed that plants in tropical and subtropical biomes had the largest diameter range of their finest root tips. This suggests that the plants rely on soil fungi which can be found abundantly in wet, warm tropical soils. The researchers referred to these types of biomes, which have soil that is consistently rich in nutrients, as being “predictable.”
Biomes considered to be “unpredictable” are characterized by infrequent precipitation, poor soil, or cold winters. The researchers found that root tips in these less predictable biomes had evolved to be significantly thinner so that the plants could more efficiently explore the soil and have less dependence on symbiotic fungi.
“Interestingly, little was known about how plant roots have evolved to facilitate success in their native habitats,” said Professor Kurt Pregitzer. “Now we know that leaves and roots have responded to different evolutionary selective pressures, and we can start building a better understanding of how root form and function drive plant success within the tremendous biological diversity we see on Earth.”
Hedin explained that the research may provide critical insights for protecting endangered species and for predicting how plants will adapt to climate change.
“This work has major implications for conservation and our stewardship of the plant world,” said Hedin. “It provides some of the hidden, below-ground rules by which plants survive and spread. It’s a global view of plant evolution at a time when global rules are essential for building climate models and understanding the biosphere.”
The study is published online in the journal Nature.
1965: The year human-induced changes to Earth officially began
For the first time, researchers have found scientific evidence to pinpoint when mankind entered into the current geological age known as the Anthropocene. A radiocarbon spike located in the heartwood of a Sitka spruce tree represents the precise time in 1965 that humans changed our planet forever.
Many scientists agree that we have entered into a new epoch marked by human-induced changes to the Earth, which is referred as the Anthropocene. In order for a new era to be declared, however, there has to be a clear, global signal that marks its official beginning.
The radioactive carbon spike, which was created by atmospheric thermonuclear bomb tests in the 50s and 60s, has provided experts with the proof that they have been searching for.
Study co-author Christopher Fogwill is a professor of Glaciology and Palaeoclimatology at Keele University.
“The impact that humanity’s nuclear weapons testing has had on the Earth’s atmosphere provides a global signal that unambiguously demonstrates that humans have become the major agent of change on the planet,” said Professor Fogwill.
“This is an important, yet worrying finding. The global atomic bomb signal, captured in the annual rings of this invasive tree species, represents a line in the sand, after which our collective actions have stamped an indelible mark, which will define this new geological epoch for generations to come.”
The Sitka spruce tree, located on Campbell Island in the Southern Ocean, is over 100 years old and native to the North American Pacific Coast. It was planted on the island in 1901 by the governor of New Zealand. The spruce is referred to as the “loneliest tree in the world” because it stands over 100 miles away from the nearest tree on the Auckland Islands.
“It seems somehow apt that this extraordinary tree, planted far from its normal habitat by humans has also become a marker for the changes we have made to the planet, it is yet further evidence, if that was needed, that in this new epoch no part of our planet remains untouched by humans,” said study co-author Mark Maslin.
Professor Chris Turney from the University of New South Wales is the study’s lead author.
“We were incredibly excited to find this signal in the Southern Hemisphere on a remote island, because for the first time it gave us a well defined global signature for a new geological epoch that could be preserved in the geological record,” said Professor Turney.
“Thousands of years from now this golden spike should still stand as a detectable marker for the transformation of the Earth by humankind.”
Although evidence of the radiocarbon peak had been previously found preserved in European trees, the signal did not yet qualify as the marker of a new epoch.
Now that the signature has also been identified in the Southern Hemisphere, it is considered an official signal because it is global, precise, and detectable in the geological record.
The study is published in Scientific Reports.
Plants first began covering the Earth 520 million years ago
Until now, it had been widely believed that plants first colonized the planet 420 million years ago, creating lush, green spaces across the continents that would later become suitable habitats for land animals.
But now, new research has found that plants actually spread across the Earth 100 million years earlier, calling into question our knowledge of early Earth and the evolution of its biosphere.
Previous theories of plants first appearing on land came from studies of the oldest plant fossils, which dated back 420 million years.
However, researchers from the University of Bristol, Cardiff University, and the Natural History Museum used molecular clock dating methods to find that these fossils are not proof of the first on Earth.
“The fossil record is too sparse and incomplete to be a reliable guide to date the origin of land plants,” said Mark Puttick, a lead author of the study. “Instead of relying on the fossil record alone, we used a ‘molecular clock’ approach to compare differences in the make-up of genes of living species – these relative genetic differences were then converted into ages by using the fossil ages as a loose framework.”
Their findings were published in the journal Proceedings of the National Academy of Sciences.
Molecular clock methodology combines evidence on the genetic differences between both fossils and living species.
By examining the genetic data, the researchers were able to pinpoint an evolutionary timeline based on shared ancestors of fossils and living plant species today.
The researchers also examined atmospheric data to understand how early plant species shaped the Earth’s climate.
“Previous attempts to model these changes in the atmosphere have accepted the plant fossil record at face value – our research shows that these fossil ages underestimate the origins of land plants, and so these models need to be revised,” said Jennifer Morris, a lead co-author of the study.
Taking all these factors into consideration, the more accurate estimate shows that plants likely first colonized Earth 520 million years ago.
The research team made sure to test if different relationships between early land plants changed their origin timeline.
“We used different assumptions on the relationships between land plants and found this did not impact the age of the earliest land plants,” said Philip Donoghue and Harald Schneider, leaders of the research.
“Any future attempts to model atmospheric changes in deep-time must incorporate the full range of uncertainties we have used here.”
The results show that land plants likely formed on Earth much earlier than previously thought and sheds new insight into Earth’s early climate and biosphere.
Farming with crushed rocks can help soak up carbon
The soil around volcanoes is some of the most fertile on Earth. When ash and sediment erupt from a volcano in a pyroclastic flow, these deposits can quickly break down in the surrounding soil and form mineral-rich dirt that is ideal for crops.
Now, new research has found that it’s possible to mimic this mineral-rich effect and also soak up carbon dioxide by adding crushed rocks to farmland. As the rocks dissolve in the soil, they release vital nutrients and create ideal conditions for agriculture.
The study was conducted by researchers from the University of Sheffield along with an international team of scientists and is the first of its kind to suggest mineral rich soils as a solution to help mitigate carbon emissions.
Their findings were published in the journal Nature Plants.
“Human societies have long known that volcanic plains are fertile, ideal places for growing crops without adverse human health effects, but until now there has been little consideration for how adding further rocks to soils might capture carbon,” said David Beerling, the lead author of the study.
The key, according to the study, lies in adding fast-acting silicate rock deposits, such as crushed basalt, to farmlands and soil. The minerals would add a barrier against pests and disease and aid in carbon capture.
Some added benefits of using this method, which is called enhanced rock weathering, are that it wouldn’t take away possible croplands or put a strain on water resources.
The silicate rocks could be added to any soils, but the study suggests that arable lands capable of being plowed for crops is the optimal place to start.
Several arable farms already put crushed limestone in the soil, so the materials and equipment needed to try enhanced rock weathering are already in place.
Enhanced rock weathering could help ensure future global food security and provide a new outlet for soaking up carbon.
“The magnitude of future climate change could be moderated by immediately reducing the amount of CO2 entering the atmosphere as a result of energy generation,” said Beerling. “Adopting strategies like this new research that actively remove CO2 from it can have a massive impact and be adapted very quickly.”
The researchers are hopeful their methods could be used to create nutrient soil that helps in mitigating the effects of climate change.
“Strategies for taking CO2 out of the atmosphere are now on the research agenda, and we need realistic assessment of these strategies, what they might be able to deliver, and what the challenges are,” said James Hansen from the Earth Institute at Columbia University, a co-author of the study.
Tiny proteins offer huge insight into how circadian clock ticks
Your circadian rhythm guides your body through 24 hours, telling you when you feel most awake and most asleep. Most life forms on Earth – including bacteria, plants and animals – have a circadian clock guiding them through each day and night.
But what makes them tick?
Dr. Andy LiWang of the University of California, Merced has been studying circadian rhythm – specifically, the circadian clock of blue-green colored cyanobacteria. Using nuclear magnetic resonance spectroscopy, he and his lab have studied certain proteins in the cyanobacteria move hour by hour, and seem to regulate the bacteria’s circadian rhythm.
“And now it’s becoming clear that the same is true for [animal] clocks,” LiWang said in a press release.
Dubbed circadian clock proteins, the proteins from cyanobacteria are unique because they can be studied in a test tube without live cells. With the help of adenosine triphosphate, the scientists were able to create a circadian clock that ran for weeks, giving them an extensive look on how circadian rhythm works.
“We also examine how the proteins wiggle, flex, and shape-shift, because these motions … are also critical to their biological function,” LiWang said.
His lab also worked with X-ray crystallographer Dr. Carrie Partch at the University of California, Santa Cruz to produce high-resolution images of the microscopic proteins.
“A big surprise for us was the extent to which internal motions of circadian clock proteins dictate … their function,” LiWang said. “Static X-ray crystal structures of individual proteins, mostly solved by other labs, were invaluable to our work but told only part of the story.”
While the cyanobacteria’s circadian clock proteins have offered a new glimpse into how circadian rhythm works, more research is needed, LiWang said. They’re not identical to the clock proteins of plants, animals or humans, but they should share some similarities, he said.
“Because clock proteins need to keep time, there should be some basic principles of biological timekeeping shared between all clocks regardless of whether the proteins are the same or not,” he said.
Coffee production is actually good for the birds, too
A team of scientists set out to determine which type of coffee bean farms are the most beneficial to forest wildlife. The researchers investigated the relationship between bird diversity and the two primary coffee types, Arabica and Robusta.
Wildlife Conservation Society Associate Conservation Scientist Dr. Krithi Karanth teamed up with experts at Princeton University and the University of Wisconsin-Madison to investigate bird diversity on coffee plantations in the Western Ghats mountain region of India.
Previous studies have shown that shade-grown coffee, which is typically Arabica, promotes significant levels of biodiversity.Now that coffee production is globally shifting toward Robusta, experts are concerned this may be detrimental to wildlife because this coffee requires a more intensive cultivation process with direct sunlight.
The study revealed that Arabica bird populations were more species rich, but the researchers were surprised to find that Robusta also provided substantial biodiversity benefits. In addition, Robusta was found to support large populations of several sensitive bird species.
The study authors identified a total of 79 forest-dependent species living in the coffee plantations they surveyed, including three threatened species. These farms also promote mammal, amphibian, and tree diversity.
“Coffee farms already play a complementary role to protected areas in a country like India where less than four percent of land is formally protected,” said Dr. Karanth.
“Therefore, building partnerships with largely private individual and corporate land holders will provide much needed safe-passage and additional habitats for birds and other species.”
Indian Robusta receives relatively high flavor ratings by coffee experts and commands a price premium. Furthermore, farmers use less pesticides in the Robusta farmlands, which are more disease-resistant.
“An encouraging result of the study is that coffee production in the Western Ghats, a global biodiversity hotspot, can be a win-win for birds and farmers,” said lead author Charlotte Chang.
The study is published in the journal Scientific Reports.
Image Credit: Manish Kumar
More species of wild bees means more crops for humans
Researchers at Rutgers University have confirmed a link between increased pollination and a larger number of wild pollinator species. The experts are reporting that more species of wild bees are needed for vast regions of crops to thrive.
The study was focused on 48 farms in New Jersey and Pennsylvania over the course of several years. The team collected and identified more than 100 species of wild bees that were observed pollinating crop flowers. Over half of the species examined were needed for pollination on at least one of the farms.
“Our results confirm the importance of biodiversity in keeping the planet habitable for human beings, at least if our findings apply to other ecosystem functions as well,” said lead author Rachael Winfree.
According to scientists, wild pollinators provide as much as half of the crop pollination that takes place worldwide. The role of wild pollinators may be more important now than ever before with declining populations of domestic honey bees in North America.
“I like to think of this as a real-world question,” said Winfree. “These are real farms and real farmers, and each farmer needs his crops pollinated. The answer turns out to be, that when you require that all farms are pollinated, you need an order of magnitude more bee species than has been needed in experiments.”
In earlier studies, Winfree offered recommendations for farmers and land managers who want to promote a greater presence of wild species for crop pollination.
“Farmers can plant fallow fields and road edges with flowering plants, preferably plants whose flowering periods are different, because wild pollinators need to be supported throughout the growing season,” said Winfree. “They can reduce pesticide use and avoid spraying during crop bloom when more bees are in the crop field.”
While many controlled experiments have demonstrated that increased pollination results from more species, this is one of the first studies to confirm this connection in nature.
The research is published in the journal Science.
Image Credit: Rutgers University, Rachael Winfree
How plants protect themselves from heat stress
Heat stress can have a devastating effect on plant growth and development, and can greatly reduce crop yields. Researchers at the University of Cambridge set out to gain a better understanding of how plants sense and respond to heat stress.
Plants respond to heat differently during the day compared to night time, and plants have a much better chance of survival when they are exposed to heat during the day. This is because they have adapted a cycle of resistance that helps them to endure the hottest hours of the day.
Plants use their sense of temperature to activate the production of protective heat shock proteins (HSP), yet the signaling process involved in this activation process is a mystery. Previous research has indicated that heat resistance is triggered in plants when they are exposed to light and then deactivated in the darkness.
“I was quite interested in how plants respond to their environment and was surprised that there was so much to be learned about how plants sense and respond to temperature,” said study co-author Patrick Dickinson. “There is a lot known about how plant and animal cells respond to extreme heat stress, but not much was known about their response to ambient heat or how they regulate their response to heat between day and night.”
Dr. Dickinson found that chloroplast genes are linked to plant stress response. He discovered that the chloroplast sends a signal in response to light, and this signal activates gene expression in the nucleus which protects the plant from heat stress.
“There is some sort of signal coming initially from the photosynthetic electron transport chain, which is communicated to the nucleus to activate the gene expression, but what that signal is is not clear yet,” explained Dr. Dickinson.
“It could possibly be hydrogen peroxide because that has been shown to move from the chloroplast to the nucleus to initiate signalling, but there is still a lot more that needs to be looked at to confirm the nature of the signalling.”
Study supervisor Dr. Phil Wigge stressed the importance of identifying the genes that are involved in the heat resistance of plants.
“Many of the crops being grown around the world today are already being grown at the top of their comfort zone in terms of temperature,” said Dr. Wigge. “There is actually an estimate that for major crops like wheat, rice and maize, that every degree Celsius rise in temperature above current temperatures could potentially decrease crop yields by between 3-7% due to thermal stress.”
“The contribution that we are trying to make in the lab is to understand the molecules and the underlying mechanisms that control how a plant senses temperature and the genes that are required for a plant to adapt to higher temperatures. And we hope that we can then use that information to discover the same genes in crop plants and see if those genes can be used to make crop plants more resilient to heat stress.”
The study is published in the journal Cell Reports.
Marijuana is much less damaging to the brain than alcohol
Experts at the University of Colorado Boulder are reporting that alcohol causes more damage to the brain than marijuana. Alcohol use was linked to structural changes in brain matter, while marijuana use was not linked to long-term mental consequences.
Marijuana is being legalized for both medicinal and recreational use in states across America, and researchers are working to learn more about its potential health benefits as well as any harmful impacts that may be caused by the drug.
The CU Boulder team set out to examine how marijuana affects the brain. The experts analyzed MRI scans from over 1,200 participants between the ages of 14 and 55 after determining patterns of alcohol and cannabis use among the individuals.
The study revealed that marijuana does not significantly affect grey or white matter in the brain. Alcohol use, on the other hand, was found to reduce the size of grey matter and the integrity of white matter – particularly in adults who had used alcohol for many years.
Grey matter enables brain function such as speech, muscle control, decision making, and memory, while white matter connects areas of grey matter together. The researchers explained that any reduction in the size or integrity of brain matter can lead to impairments in brain functioning.
“With alcohol, we’ve known it’s bad for the brain for decades,” said study co-author Kent Hutchison. “But for cannabis, we know so little.”
Hutchison pointed out that the results of previous studies on how marijuana affects the brain are inconsistent.
“When you look at the research much more closely, you see that a lot of it is probably not accurate,” said Hutchison.
“When you look at these studies going back years, you see that one study will report that marijuana use is related to a reduction in the volume of the hippocampus. The next study then comes around, and they say that marijuana use is related to changes in the cerebellum…The point is that there’s no consistency across all of these studies in terms of the actual brain structures.”
Based on the findings of the current study, the researchers believe that alcohol consumption is much more harmful to brain health than marijuana use.
“While marijuana may also have some negative consequences, it definitely is nowhere near the negative consequences of alcohol,” said Hutchison.
The study is published in the journal Addiction.
These crops will confuse global warming with change of season
Researchers at the John Innes Centre in England set out to examine how changing environmental conditions affect seed dispersal in plants. They found that rising temperatures will cause many species of crops in the cabbage and mustard family to prematurely release seeds, which is detrimental to the reproductive process.
“In many crops, such as oilseed rape, premature seed dispersal is one of the major causes of crop loss. In the context of climate change, this could become increasingly severe,” explained co-author Vinod Kumar. “This study exposes the potential vulnerabilities of crop production in the warming world and paves the way for addressing this problem.”
Plants adjust their cycles according to a range of environmental conditions. They endure daily changes in weather and temperature, yet remain aligned with the seasons.
“Seed dispersal is also a key trait that must be controlled when domesticating plants for food production,” said co-senior author Lars Ostergaard. “With the prospect of climate change affecting crop performance, we wanted to understand how environmental signals such as temperature affect seed dispersal.”
The team focused its investigation on Arabidopsis plants, which belong to the mustard or cabbage family. When the researchers exposed the plants to temperatures elevated from 22 degrees Celsius to 27 degrees Celsius, they found that the plants opened their seed pods earlier and released seeds.
The experts determined that the rise in temperature had promoted the expression of the INDEHISCENT gene, which is known to regulate the development of seed pod tissue and promote fruit opening.
“We speculate that such mechanisms have evolved to facilitate proper seasonal timing of dispersal to ensure that seeds are released under conditions that are both timely and climatically optimal for germination,” said study first author Xin-Ran Li. “There could perhaps be a selective advantage in early maturation and dispersal in the wild.”
The researchers plan to further investigate the mechanisms involved when seed dispersal is altered by elevated temperatures.
“We are hopeful that by understanding this in detail, we will be better equipped to devise strategies to breed for crop resilience to climate change,” said Ostergaard.
The study is published in the journal Molecular Plant.
Florida’s citrus trees struggle to recover from disaster, disease
Just as the citrus industry in Florida was expected to recover from years of serious disease, Hurricane Irma struck and further devastated crops. The disaster turned 2017 into the worst year for Florida orange production since 1945, causing hundreds of millions of dollars in damage.
Florida’s first orange trees were planted by early Spanish explorers in the 1500s in St. Augustine, and Florida citrus was first commercially farmed in the mid-1800s. Florida ultimately became the global leader in grapefruit production and the world’s second largest producer of orange juice.
Beginning in 2005, Florida’s citrus production became critically threatened by a bacterial disease known as citrus greening. The disease, which is transmitted by tiny flying insects, can weaken and kill infected trees.
According to the Orlando Sentinel, citrus greening reduced orange and grapefruit revenue by $4.64 billion over just ten seasons. Greening also wiped out 30 percent of citrus industry employment between 2012 and 2015.
Citrus growers anticipated substantial production gains in 2017, until Hurricane Irma made matters much worse. According to the Florida Department of Agriculture and Consumer Services, damage from the hurricane cost the citrus industry $760 million in damages and production was lowered by 30 percent.
A disaster relief package that was passed by the Senate Friday and will now be sent on to the House includes $2.36 billion in aid for Florida citrus growers and other farmers. Senator Bill Nelson is hoping the funding will help people who are still trying to recover from the devastating hurricane season of 2017.
“The people of Florida and Puerto Rico are still struggling to recover from last year’s devastating storms and the disaster funding in this bill will help provide them some much-needed relief,” said Nelson. “The disaster funding in this bill will not only help provide Florida’s schools and citrus growers the help they need, it will also help Puerto Rico rebuild its power grid and avoid an even greater healthcare crisis.”
Marijuana could actually help battle the opioid crisis
The opioid epidemic in America has reached a new high, with over 40,00 deaths related to opioid overdoses in 2016. According to a new CNN report, the rate of heroin overdose-related deaths has increased 19 percent each year.
The current wave of opioid addiction in America got its start in the late 1990s. Pharmaceutical companies touting the miracle pain-relieving benefits of opioid drugs purposely mislead patients and doctors about the addictive effects of the drugs.
Since then, millions of people continue to misuse prescription opioids, and although treatments are available and some medications have been successful, it can be difficult for patients to get appropriate and effective treatment for their addiction.
But now, a surprising alternative has been suggested to help battle opioids, as marijuana has been shown to be effective at reducing and treating pain.
According to a new report from Live Science, marijuana could be a viable treatment for opioid addiction, as studies have shown that cannabinoids could help with chronic pain, the pain caused from some cancers, neuropathic pain, and pain from multiple sclerosis.
Even though cannabis can be somewhat addictive, it is far easier to quit and doesn’t elicit the terrible withdrawal symptoms associated with opioid dependence.
The report also highlighted a survey published in the Journal Cannabis and Cannabinoid Research, where patients who used opioids and cannabis for pain relief reported that cannabis was more successful at reducing pain.
Marijuana, like any other drug, is not without its risk and patients should consider carefully before making any drastic changes. However, based on previous studies, it could be a safer and even more effective treatment than current prescription opioids on the market today.
By Kay Vandette, Earth.com Staff Writer