A novel way to help plants survive drought

The headline that caught my attention this week was the one saying booze can help make plants drought-resistant. Has someone been imbibing too much?
It’s actually a serious study showing how plants treated with ethanol can develop a tolerance to drought conditions, thereby helping them survive extreme dry periods. Many wine regions have experienced very hot and dry conditions this vintage, with the lack of water limiting plant growth and their ability to photosynthesise, which results in severely decreased yields and poorer quality grapes.

A serious study for a serious problem, then.
This study offers a practical way to increase food production when water is scarce, without the need for costly, time-consuming, and sometimes controversial production of genetically modified plants.
It’s also timely. Heatwaves and droughts are expected to become more frequent and longer lasting due to climate change.

Okay, but it still seems odd that someone should think to pour alcohol on a plant to help it survive. When we used to do this with bad wine at my auntie’s house, the yucca plant eventually died.
While ethanol seems to negatively affect plants’ leaf growth during non-drought times, the study states that this effect is slight when compared to the chemical’s potential benefits during times of drought.
It’s known among scientists that in drought conditions, plants naturally produce small amounts of ethanol. So, some clever boffins in Japan thought, why not treat them with doses of this inexpensive and widely-available chemical?
To test their hypothesis, the researchers at the RIKEN Center for Sustainable Resource Science grew plants for about two weeks with ample water. Then, they pretreated soil with ethanol for three days, followed by water deprivation for two weeks. About 75% of ethanol-treated wheat and rice plants survived after rewatering, while less than 5% of the untreated plants survived.


After two weeks without water, wheat did not survive when soil was pretreated with water (left) but thrived when the soil was pretreated with 3% ethanol (right). The same was true for rice and the model plant Arabidopsis. Credit: RIKEN

You say ethanol, I say alcohol. How does this treatment work?
Lead researcher Motoaki Seki says that treating the soil with ethanol mitigates drought on several fronts. First, drought-related genes are expressed even before water is missing, giving the plants a head start in preparation. Then, the stomata close, allowing leaves to retain more water. At the same time, some of the ethanol is used to make a variety of sugars, which provide much needed energy that is normally difficult to get with closed stomata.

So how do you treat plants with ethanol?
A few drops in the irrigation system. 10mm worked best in this test – but that was not on vines.

And how does it work on vines?
Although the scientists used rice and wheat for their study, they say their findings “highlight a new survival strategy for increasing crop production under water-limited conditions”.

Apart from offering effective protection in drought conditions, are there any other benefits?
It’s a relatively inexpensive and environmentally friendly treatment. Ethanol is also food safe. The widespread use of ethanol for this purpose would also offset the need to genetically modify plants to make them more drought resistant or to go through laborious classical breeding methods to create drought-resistant varieties.

Fascinating. And if I want to know more?
The study was published in Plant and Cell Physiology. You can read the paper here.