How tomato plants use their roots to ration water during drought

Plants have to be flexible to survive environmental changes, and the adaptive methods they deploy must often be as changeable as the shifts in climate and condition to which they adapt. To cope with drought, plant roots produce a water-repellent polymer called suberin that blocks water from flowing up towards the leaves, where it would quickly evaporate. Without suberin, the resulting water loss would be like leaving the tap running.