Water intake by Hydathodes in CAM plants.

Abstract

CAM plants are specially adapted to withstand arid conditions for long periods without precipitation. In nature, these plants often go for extended periods of time without water intake through the roots. A few research studies have suggested that these desert plants may have an additional method for taking in water. Specialized structures in the epidermis of the leaves, called hydathodes may be responsible for foliar water uptake in the plants thus helping them to survive in arid conditions. Researchers have theorized that the remarkable ability of CAM plants to survive on such little precipitation is due in part to the presence of hydathodes. Researchers have hypothesized that the water is absorbed by the hydathodes. A number of rare or threatened members of the Crassulaceae in the genus Dudleya , are endemic to Southern California. For such plants, water uptake either directly by the leaves, or assisted by leaf morphology, could be important to their success. Occidental College has a large collection of African succulents in the Crassulaceae , and is close to field sites of a number of species of Dudleya . We propose to investigate the possibility of foliar water uptake in a variety of succulents. We also propose to examine the possible contribution of the rosette form of Dudleya to direct water flow from the surface of the leaves to the roots. Thus plan to design experiments to examine the water pathways of the Dudleya and other Crassulaceae species with respect to both direct foliar uptake and leaf-assisted water uptake due to the rosette form.