The key to drought-tolerant crops may be in the leaves

Leaf wax acts as the equivalent of ‘lip balm’ for plants, 
protecting them from the harmful effects of drought

Researchers at USC and Texas A&M University grew winter wheat in an arid area of Texas with reduced irrigation and found that the plants protect themselves by producing thick leaf wax.

A new study suggests breeding plants with a thicker layer of leaf wax is the key to greater drought tolerance and growing crops in more arid regions.

Sarah Feakins, a scientist at University of Southern California who has studied leaf wax in the context of climate change, teamed up recently with researchers at Texas A&M University to research and develop drought-resistant crops. During tests growing winter wheat the team found that the cultivars in a high and dry area of Texas generated more protective wax on their leaves as a measure to protect themselves against more extreme conditions.

The results mimicked what scientists have found in leaves in natural ecosystems: Those that survive in dry climates have higher concentrations of wax.

“Water conservation depends on innovation, and in this case, we are hoping to find one solution by identifying the traits in this important food crop that would enable the wheat plants to tolerate drought and still produce plenty for harvest,” said Feakins.

The study was published in the journal Organic Geochemistry.

All plants produce wax that helps their leaves repel water and shield the plant from insects and the elements, said Feakins, who has studied climate history of the Earth through the geochemistry of leaf wax in sediments.

For the study, the researchers grew test plots of winter wheat in two different areas of Texas. They found a trend where moisture stress caused greater leaf wax generation — an increase of nearly 50 per cent in one plot.

“We see a strong effect in the higher and drier location,” Feakins said. “We see the plants adapt to their environment.”

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