SYNTHETIC trees could one day extract and purify the traces of water held even in arid earth, and help make high-quality wines. That’s the claim of a team who have reproduced the way plants pump water to heights of many tens of metres.
For years, it was thought that capillary action couldn’t raise water more than about 10 metres, and this posed a puzzle: how do trees and other tall plants pump water from their roots to their topmost leaves? The favoured answer among plant biologists is that evaporation across the leaf membrane puts water inside the tree under “negative pressure”.…
