- Alexandra Martins
- BBC News World
6 hours
image source, Science Photo Library
Purslane remains highly productive even under drought conditions.
It is so common that it is even consumed in some countries in soups or salads.
But few suspect that this plant, considered in some places a weed or weed, has extraordinary abilities.
Portulaca oleracea, commonly known as purslaneoffers crucial clues for creating drought-resistant crops, according to a new study from scientists at Yale University in the United States.
But how does this grass manage to survive in extreme conditions of water scarcity and remain highly productive?
The secret lies in the unique way in which it carries out one of the most important processes for life on the planet: photosynthesis.
Purslane, rich in vitamins and medicinal
Before we get into the peculiarities of how this plant uses solar energy, a few more facts about purslane.
“Portulaca oleracea is a very resistant plant, capable of growing in a huge variety of ecosystems, including hot and dry areas,” Jose Moreno-Villena, the author who led the new study, told BBC Mundo. study published in the journal Science Advances.
The Spanish scientist, who carried out this work together with his colleagues when he was at Yale University, is currently a researcher at Kew Gardens, the London Botanic Garden.
image source, Getty Images
Portulaca oleracea or purslane is a plant consumed in many countries for being “rich in vitamins, minerals and antioxidants”.
“Probably many of your readers have seen this plant growing in cracks in your street sidewalks or as adventitious plants in gardens.”
“Although it goes unnoticed, purslane is rich in vitamins, minerals and antioxidants that make it a perfect ingredient to accompany meals,” he added.
And the plant is also used in traditional Chinese medicine. “Its use is gaining more and more popularity worldwide.”
Moreno-Villena and his colleagues had been studying purslane because it is not only resistant to prolonged droughts but also grows fast.
“These two traits rarely go together.“said the researcher.
What is photosynthesis and why is it different in some plants?
“Photosynthesis makes life as we know it on Earth possible,” Moreno-Villena explained.
“It is the process that allows plants to store energy from the Sun and convert it into food.”
“This process not only supports plants and animals in ecosystems around the world, but also releases oxygen into the atmosphere, while sequestering CO2 or carbon dioxide.”
image source, Jose Moreno-Villena
Jose Moreno-Villena and his colleagues sought to understand the functioning of “the molecular pieces of P. oleracea that allow it to be so successful.”
Most plants use a type of photosynthesis called C3, which works perfectly when there is plenty of water, the researcher said.
“However, in ecosystems where rainfall is scarce and temperatures are high, this type of photosynthesis does not work well, and plant growth and survival are compromised.”
To fix that problem some groups of plants evolved so-called C4 photosynthesis and CAM photosynthesisdeveloping a set of different anatomical and biochemical features that allow the production of food without needing so much water.
For example, fast-growing plants like corn and sugar cane carry out C4 photosynthesiswhich allows the plant to remain productive under high temperatures.
Succulent plants, on the other hand, like the agave or the cactus, carry out photosynthesis CAM. “This is the case, for example, of the Saguaro cacti in the desert. These plants are characterized by very slow growth. They leave part of their metabolism for the night when the temperature is lower, thus reducing water loss.”
Why purslane is different
What makes purslane extraordinary is that it has both C4 and CAM evolutionary adaptations at the same time, and they are “fully integrated.”
“Until now it was a mystery how both types of photosynthesis could work within the same leaf. Our studies show that These two systems work on the sameos types of cells and share part of the biochemical ‘machinery’, which allows their integration“.
“When conditions are favourable, Purslane oleracea uses C4 to grow explosively, but under drought conditions CAM is initiated as an accessory pathway that supplies compounds to the C4 cycle, preventing it from stopping production”.
“Therefore, the integration of C4 and CAM provides unusual levels of protection in times of drought.”
Why discovery matters
The researchers used in their study novel techniques called “spatial gene expression technologies“.
“They make it possible to visualize the amount of expression of each gene in each type of tissue or cell,” Moreno-Villena explained.
“These methods are very new and have been used mainly in animal samples, but we have been pioneers in using them in plant leaves.”
image source, Getty Images
In purslane, two types of photosynthesis that allow plants to be more resistant to drought “are fully integrated.”
It was thus possible to identify for the first time the location of the enzymes in the different cell types of the leaves that allow the two types of photosynthesis to be connected.
Their observations were contrasted with computational metabolic models developed by researcher Haoran Zhou for the study, which demonstrated the efficiency of this mechanism under water deficit conditions.
The results of the study could be used in the production of crops more resistant to droughtwhich will be more prolonged and severe in some regions due to global warming, according to the United Nations Panel on Climate Change, IPCC for its acronym in English.
Colin Osborne, a professor of plant biology at the University of Sheffield in England who was not involved in the study, summed up its importance.
“Many wild plants have evolved ways to become more productive in hot conditions or to become very resistant to drought.”
“However, we previously thought that two of the most important adaptations to achieve these goals could not occur in the same plant,” Osborne told BBC Mundo.
“Moreno-Villena and his colleagues showed that these components can be coordinated to allow both adaptations at the same time. Their research can inspire scientists working to achieve more productive crops that require less water.”
image source, Science Photo Library
The results of the purslane study could be used in the production of more drought tolerant crops.
Can there be other plants like the purslane?
Moreno-Villena and his colleagues hope to use the same novel technology from this study in other plants.
“Plants tend to evolve traits repeatedly and we speculate that there may be many other species with this adaptation,” the scientist told BBC Mundo.
“There are about 390,000 known plant species, each with different traits and metabolic and genetic variations that allow them to thrive in their environment.”
“We continue to learn new aspects of photosynthesis every day.”
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