Leaf-drinkers in water scarcity!

In school class room it was taught that transpiration is one of the plant's physiological functions. But do we know that 'reverse transpiration' is also a physiological function? Yes, it is so - in certain plants! In them leaf takes in water and sends it to the stem - reverse of what we learnt and expect - root takes in water and sends it to leaves via stem. These plants are described as 'Leaf - drinkers,' as their leaves are 'drinking' water.
Such plants are seen in deserts. In Atacama desert there has been no rain at all for the past fifty years . But there are trees and plants (cacti and algae) in it! They do live in it without rain water, but with water they drink from air moisture! When air is heated at daytime by the sun's rays it holds more water; but at night time the cold air present in the desert tends to lose water. Now the thirsty leaves of these desert plants take in moisture from air. In rain-fed areas of our Earth also there are such leaf- drinkers. But they become leaf- drinkers only whenever they encounter drought in their area. One among them is: Pygmy Cedar tree (Peucephyllum schottii, Desert Fir). Another interesting feature of such trees is that the pure distilled water they drink from air wash out salts and other toxic matters from their systems, thus making them the best fodder for rearing healthy farm animals!
This is a wonder phenomenon found in these plants - an adaptation to both of their climate and weather conditions!