PARENT SESSION
Poster Session # 15: Plant Ecology.

Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

Drought recovery via foliar water absorption: Bypassing the soil uptake pathway.

Goddard, Kelly^*,1, Breshears, David^*,1, Martens, Scott^*,1, Dayem, Katherine ¹, Meyer, Clifton ¹, ¹ Los Alamos National Laboratory, Los Alamos, NM

ABSTRACT- Woody plants benefit form large pulses of water that penetrate deeper into the soil profile. During drought, such pulses are non-existent and the only precipitation that may occur is likely to be in the form of small precipitation events. Small precipitation events are likely to penetrate the soil only to near-surface depths and to be subject to rapid soil evaporation. Here we document a mechanism for addressing drought recovery via foliar absorption in a woody juniper species, Juniperus monosperma. We excluded precipitation by installing a shelter located beneath the tree canopies and above the soil. Predawn plant water potentials of treated trees tracked control trees during the first monthly interval after initiation of rain, suggesting that 100% of the recovery could be due to foliar absorption. They exhibited ∼33% of the recovery of control trees the following month. Hence nearly 50% of the overall recovery was attributable to foliar absorption. To confirm that foliar absorption was occurring and was important during drought, we compared control branches with treated branches, which we poured water over to establish foliar uptake. We found that treated branches responded significantly relative to control branches. This work highlights an important mechanism of water uptake in a semiarid species that allows bypassing of soil water uptake.

Key words: absorption, foliar