According to a recent study conducted at the RIKEN Center for Sustainable Resource Science in Japan, ethanol can help plants survive drought. The researchers, under the direction of Motoaki Seki, demonstrate that after two weeks without water, plants, including rice and wheat, can flourish when ethanol is added to the soil. The study was published in Plant and Cell Physiology.
Ways to Prolong Plants' Life During Drought
Finding a strategy to stop plants from dying when they are deprived of water is one solution to avoid future food shortages. One of these strategies is modifying plants genetically to keep the stomata close. This technique succeeded as it prevented the water from leaving the plants. However, producing genetically modified plants is costly and time-consuming, and access to these modified crops may not be equally available to all countries.
As an alternative, ethanol can be used on the soil. According to the experts, plants that lack water start to make ethanol. The chemical can therefore shield the plants from upcoming droughts.
The Benefits of Pretreating Soil with Ethanol
The discovery of ethanol production in plants provides a useful method to enhance food production globally when water is in short supply. Ethanol is a cheap alternative without the need for the expensive, time-consuming, and occasionally contentious manufacture of genetically engineered plants.
According to Seki, applying exogenous ethanol to common crops like wheat and rice can boost crop productivity during a drought. Like in Arabidopsis, the drought-stress response is presumably regulated by alterations in the metabolomic and transcriptome profiles.
Seki claims that adding ethanol to the soil has many advantages for preventing drought. One of the advantages is that the drought-related genes are expressed before the water supply runs out—this aids in preparing the plants for the impending drought.
At that time, the stomata close, allowing the leaves to hold more water. A portion of the ethanol is also changed into other sugars, which provide much-needed energy that is normally difficult to access with closed stomata.
An Experiment to Test a Hypothesis
The researchers gave plants enough water for roughly two weeks to grow to test the hypothesis. The soil was then pretreated with ethanol for three days, followed by two weeks of water deprivation. After rewatering, almost 75% of the wheat and rice plants exposed to ethanol survived, but less than 5% of the untreated plants did.
The researchers focused on Arabidopsis, a tiny flowering plant widely used in plant biology as a model organism. The mustard (Brassicaceae) family, which includes cultivated species like cabbage and radish, has Arabidopsis.
The researchers started by examining the leaves of the Arabidopsis. Then they discovered that as soon as water was removed from ethanol-treated Arabidopsis plants, their stomata closed, and the temperature of their leaves increased. These plants had maintained more water in their leaves by 11 and 12 days of water deprivation than the untreated plants.
The scientists then radio-tagged the ethanol before pretreatment and examined gene expression before and after water deprivation. This made it possible for them to see the processes brought on by drought and what transpired to the ethanol once the plant roots absorbed it.
The ethanol-treated plants started expressing genes typically expressed during water deprivation even before the plants were deprived of water. Additionally, the ethanol-treated plants were producing sugars from the ethanol and engaging in photosynthesis while the water level of untreated leaves was decreasing.
How is Ethanol Made?
According to the US Department of Energy, most ethanol generated in the US comes from starch-based crops processed in dry or wet mills. Due to lower initial expenses, dry mills make up about 90% of ethanol plants.
Another option is through cellulosic feedstocks. But it takes more work to produce ethanol from it than from crops with a starch-based structure, such as grass, wood, and crop wastes.
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