Not such a pest after all! Common garden weed purslane is a ‘SUPER PLANT’ that holds the key to drought-resistant crops, scientists claim
- Purslane is a common weed that many people struggle with in their gardens
- The plant is able to endure drought while remaining highly productive
- In a new study, researchers found the plant integrates two distinct metabolic pathways to create a novel type of photosynthesis
Purslane can be a nightmare for keen gardeners, but a new study may make you think twice about getting rid of the weed.
Researchers from Yale claim that purslane may be a ‘super plant’ that holds the key to drought-resistant crops.
In their study, the researchers found that the plant integrates two distinct metabolic pathways to create a novel type of photosynthesis.
This allows the weed to endure drought, while remaining highly productive.
‘This is a very rare combination of traits and has created a kind of ‘super plant’ — one that could be potentially useful in endeavours such as crop engineering,’ said Professor Erika Edwards, senior author of the study.
Purslane can be a nightmare for keen gardeners, but a new study may make you think twice about getting rid of the weed
What is purslane?
Purslane, Portulaca oleracea, is an edible, leafy, frost-tender plant widely used as an herb and salad vegetable.
The fleshy reddish stems are densely clothed with lobed leaves that are either green or golden in colour, depending on the variety, and grow to 15-20cm high.
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 synthesise nutrients from carbon dioxide and water.
Over time, different species have independently evolved a range of distinct mechanisms to improve this process.
For example, corn and sugarcane 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.
While C4 and CAM serve different functions, they both use the same biochemical pathway to act as ‘add-ons’ to basic photosynthesis.
Previous studies have shown that purslane possesses both the C4 and CAM adaptations, allowing the plant to be productive and tolerant during droughts.
However, until now, it was believed that C4 and CAM operated independently within the leaves.
In their new study, the researchers showed that C4 and CAM activity are totally integrated in purslane.
In their study, the researchers found that the plant integrates two distinct metabolic pathways to create a novel type of photosynthesis. This allows the weed to endure drought, while remaining highly productive
The researchers studied gene expression in the leaves of purslane, and found C4 and CAM both operate in the same cells, with products from the CAM reactions being processed straight into the C4 pathway.
The researchers hope the findings could help pave the way for drought-resistant crops in the future.
‘In terms of engineering a CAM cycle into a C4 crop, such as maize, there is still a lot of work to do before that could become a reality,’ Professor Edwards explained.
‘But what we’ve shown is that the two pathways can be efficiently integrated and share products.
‘C4 and CAM are more compatible than we had thought, which leads us to suspect that there are many more C4+CAM species out there, waiting to be discovered.’
The study comes as parts of the UK experience the driest conditions since the drought of 1976.
Worryingly, the Met Office has warned of ‘very little meaningful rain’ on the horizon – with conditions now so extreme that a hosepipe ban affecting one million people across Hampshire and the Isle of Wight will come into force at 5pm today.
The Met Office says it’s still too early to know how long the hot spell will last.
However, it reassures ‘there are indications of a return to more changeable 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 in the process.
The leaves of green plants contain hundreds of pigment molecules (chlorophyll and others) that absorb light at specific wavelengths.
When light of the proper wavelength strikes 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 required for photosynthesis to proceed.
The electron ‘hole’ left behind in the chlorophyll molecule is used to ‘split’ water to oxygen.
Hydrogen ions formed during the water-splitting process are eventually used to convert carbon dioxide to glucose energy, which the plant used to grow.