In Riparian and moist zones of the Santa Monica Mountains of Southern California, ferns flourish. However, the Mediterranean climate they live in is subject to drought, and the area is currently facing the worst drought it has ever seen. With little moisture in the ground and streams drying up, these ferns are running out of sources of water. However, being on the coast, the area is subject to fog nightly. This research was done to see if ferns can do leaf foliar absorption, getting their water source from the air rather than the ground. We hypothesized that ferns do leaf foliar absorption, and that fern species with higher unit leaf area will absorb more water. We tested on two species of the seven that live in the area, Pentagramma triangularis and Polypodium californicum. Polypodium has rounder, larger fronds than Pentagramma, therefore we expected to see a difference if the hypothesis is correct. To do this we used a Scholander-Hammel Pressure Chamber, and standardized the xylem pressure in each fern to -10 bars. Then the ferns were submerged for thirty minutes each and the water potential was taken again. In between each step we took the mass, and at the end of the experiment we took the dry mass and surface area. We found significant results, especially when looking at the Polypodium californica, which is indicated in the graphs. This suggests that leaf foliage absorption occurs in ferns.
Choe, Justin; Larios, Carlos; Prorok, William; and Pierce, Emily Rose, "Leaf Foliar Absorption in Pentagramma triangularis and Polypodium californicum" (2014). Pepperdine University, Featured Research. Paper 106.