Natures wonders: desert plant drinks fog (Introduction)

by David Turell , Monday, June 06, 2016, 21:06 (3090 days ago) @ David Turell

Water is scarce in the desert, and this moss uses a neat trick to stay hydrated:-https://www.newscientist.com/article/2092453-desert-plant-seen-drinking-fog-and-mist-with-its-leaves/-"A common desert moss sucks water directly out of the air instead of from the ground. The discovery could be used to inspire ways of collecting clean drinking water in developing countries.-"Most desert plants, including cacti, rely on extensive root systems to mop up scarce groundwater. But the desert moss Syntrichia caninervis collects fresh water straight from the atmosphere.-"Tiny fibres attached to the tips of the moss leaves, known as awns, allow S. caninervis to harvest fog and mist droplets, says Tadd Truscott of Utah State University, who filmed the plant's drinking behaviour.-***-"The camera images show water vapour condensing on nano-sized grooves on the surface of the awns. Miniature barbs then push this water into larger droplets that move along the length of the awn into the leaf.-“'The droplet can travel from the awn to the leaf as fast as 10 to 20 millimetres per second,” says Truscott.-"Two other plant species have previously been found to possess fog-harvesting abilities - the cactus Opuntia microdasys and the alpine plant Cotula fallax - but S. caninervis is the first species in which a detailed mechanism involving barbs and grooves has been elucidated."-Comment: That other plants do this is 'convergence' in evolution, but this report raises the usual chicken/egg issue. How did these plants live before evolution developed the mechanism, or did they arrive in a saltation fashion. If they existed in a rainy area which then changed, why do they look like mosses ( no roots) in the first place.