July 2, 2009

Desert ruhbarb eyed by scientists

Israeli scientists say they have discovered the self-watering mechanism of the Negev desert rhubarb, which harvests 16 times more water than other plants.

Researchers at the University of Haifa-Oranim said the desert rhubarb grows in the mountains of Israel's Negev desert, where average precipitation is particularly low. Unlike most other desert plants that have small leaves to minimize moisture loss, the desert rhubarb 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 slightly more than three feet.

Professors Simcha Lev-Yadun, Gidi Ne'eman and Gadi Katzir discovered the plant while studying the desert area with students. They noticed the plant's leaves are covered with a waxy cuticle and each leaf has an exceptionally ridged structure.

The scientists discovered the deep and wide depressions in the leaves create a channeling mountain-like system by which rain water is channeled toward the ground surrounding the plant's deep roots. Other desert plants, the scientists said, simply suffice with the rain water that penetrates the ground in its immediate surroundings.

The researchers said their findings show the natural selection process has resulted in the evolution of this plant's extremely large leaves, which improved its ability to survive in the arid climate of the desert.

We know of no other plant in the deserts of the world that functions in this manner, the researchers said.