Simcha Lev-Yadun, Gadi Katzir, and Gidi Ne'eman, all from the Department of Science Education—Biology, at the University of Haifa, Israel wrote their results in the journal Naturwissenschaften, which was published online on November 22, 2008.
The desert rhubarb plant is scientifically identified as the species Rheum palaestinum (family, Polygonaceae). It is a perennial hemicryptophyte (buds near or at the level of soil) that grows in the rainy season of mountainous areas in Israel and Jordan. The plant produces one to four large round leaves that are located on the ground.
They state in their abstract, “These leaves differ markedly from the typical small leaves of most desert plants. Moreover, they have a unique 3D morphology resembling a scaled-down mountainous area with well-developed steep drainage systems, raising the question which selective agents were involved in their evolution.”
The Israeli researchers state that these large leaves collect rainwater and directs it to its root system.
They state, “We measured the seasonal course of leaf growth, examined the area of wet soil surrounding the root after actual and simulated rain, and modeled the water harvesting capacity using the plant leaf area and the weekly precipitation. We show that even in the slightest rains, water flows above the veins to the leaf’s base where it irrigates the vertical root.”
And, “A typical plant harvests more than 4,100 cm3 [cubic centimeters] of water per year, and enjoys a water regime of about 427 mm/year [millimeters per year], equivalent to the water supply in a Mediterranean climate. This is the first example of self-irrigation by large leaves in a desert plant, creating a leaf-made mini oasis."
For more information on this exciting discovery, please read the May 14, 2009 BBC News article “The plant that can water itself.”
Further research into this plant could help to provide more plant growth in arid, desert-like climates around the world.