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Not such a plague after all! Common garden herb purslane is a ‘SUPERPLANT’ that holds key to drought-resistant crops, scientists claim
- Purslane is a common weed that many people struggle with in their gardens
- The plant is drought resistant and remains highly productive
- In a new study, researchers found that the plant integrates two different metabolic pathways to create a new type of photosynthesis
Purslane can be a nightmare for avid gardeners, but a new study may have you thinking about getting rid of the weeds.
Yale researchers argue that purslane may be a “superplant” that holds the key to drought-resistant crops.
In their study, the researchers found that the plant integrates two different metabolic pathways to create a new type of photosynthesis.
This allows the weeds to withstand drought while remaining highly productive.
“This is a very rare combination of traits and has created a kind of ‘superplant’ — one that could potentially be useful in efforts such as crop technology,” said Professor Erika Edwards, senior author of the study.
Purslane can be a nightmare for avid gardeners, but a new study may make you think twice about getting rid of the weeds
What is purslane?
Purslane, Portulaca oleracea, is an edible, leafy, frost-sensitive plant widely used as an herb and salad vegetable.
The fleshy reddish stems are densely covered with lobed leaves that are green or golden depending on the variety, and grow to 15-20 cm in height.
Purslane grows quickly from seed and leaves are ready to pick in 6-8 weeks.
Photosynthesis is the process by which green plants use sunlight to synthesize nutrients from carbon dioxide and water.
Over time, different species have independently developed a range of different mechanisms to enhance this process.
For example, corn and sugar cane have evolved ‘C4 photosynthesis’, which allows them to remain productive under high temperatures.
Meanwhile, cacti and agaves have evolved ‘CAM photosynthesis’, which allows them to thrive in areas with little water.
Although C4 and CAM have different functions, they both use the same biochemical pathway to act as ‘add-ons’ for basic photosynthesis.
Previous studies have shown that purslane possesses both the C4 and CAM adaptations, which allow the plant to be productive and tolerant during droughts.
Until now, however, it was believed that C4 and CAM acted independently in the leaves.
In their new study, the researchers showed that C4 and CAM activity are fully integrated in purslane.
In their study, the researchers found that the plant integrates two different metabolic pathways to create a new type of photosynthesis. This allows the weeds to endure drought and remain highly productive
The researchers studied gene expression in purslane leaves and found that C4 and CAM both act in the same cells, processing products of the CAM reactions directly in the C4 pathway.
The researchers hope the findings could pave the way for drought-resistant crops in the future.
“When it comes to engineering a CAM cycle in a C4 crop, such as maize, there is still a lot of work to be done before that can become a reality,” explains Professor Edwards.
“But what we’ve shown is that the two paths can be efficiently integrated and products can be shared.
“C4 and CAM are more compatible than we thought, which leads us to suspect that there are many more C4+CAM species waiting to be discovered.”
The study comes as parts of the UK are experiencing the driest conditions since the 1976 drought.
Worryingly, the Met Office has warned of ‘very little meaningful rain’ on the horizon – with conditions now so extreme that a ban on garden hoses for a million people in Hampshire and the Isle of Wight comes into effect at 5pm today.
The Met Office says it’s too early to know how long the heat wave will last.
However, it reassures: “There is evidence of a return to more volatile conditions from about mid-August.”
HOW DOES PHOTOSYNTHESIS WORK?
Photosynthesis is a chemical process used by plants to convert light energy and carbon dioxide into glucose for the plant to grow, releasing oxygen.
The leaves of green plants contain hundreds of pigment molecules (chlorophyll and others) that absorb light at specific wavelengths.
When light of the correct wavelength hits one of these molecules, the molecule enters an excited state — and energy from this excited state is shuttled along a chain of pigment molecules until it reaches a specific type of chlorophyll in the photosynthetic reaction center.
Here, energy is used to drive the charge separation process necessary for photosynthesis to proceed.
The electron ‘hole’ that remains in the chlorophyll molecule is used to ‘split’ water into oxygen.
Hydrogen ions formed during the water splitting process are eventually used to convert carbon dioxide into glucose energy, which the plant used to grow.