ScienceDaily (July 5, 2009) -- Researchers from the University of Haifa-Oranim have managed to make out the "self-irrigating" mechanism  of the desert rhubarb , which enables it to harvest 16 times the amount of water collected by other plants in the Negev Desert. This is the first example of a self-irrigating plant worldwide. The desert rhubarb grows in the mountains of Israel's Negev desert, where average rainfall is particularly low (75 mm per year). Unlike most of the other desert plant species, which have small leaves so as to reduce water loss, this plant is unique in that its leaves are particularly large; each plant's rosette  of one to four leaves reaches a total diameter  of up to one meter.  Prof. Simcha Lev-Yadun, Prof. Gidi Ne'eman and Prof. Gadi Katzir came across this unique plant while studying the field area with students of the Department of Science Education-Biology of the University of Haifa-Oranim, and noticed that its waxy leaves are unusually large. They observed an exceptionally ridged  structure on each leaf.  The scientists explained that these deep and wide depressions in the leaves create a "channeling" mountain-like system by which the rain water is channeled toward the ground surrounding the plant's deep root. Other desert plants simply absorb the rain water that goes through the ground in its immediate surroundings.  The desert rhubarb is able to harvest quantities of water that are 16 times the amount of water harvested by the small-leafed plants of the Negev desert region. When the research team watered the plant artificially, they observed how the water flows along the course of the leave's depressions to the ground surrounding the plant's single root and then goes through the ground to a depth of 10 cm or more. Under the experimental conditions, water goes through the ground only as deep as 1 cm.  "We know of no other plant in the deserts of the world that functions in this manner," the researchers concluded. Scientists discover the desert rhubarb can irrigate itself with its  _  .
leaves root flowers fruit