Abstract Detail

Physiology

Tucker, Lauren [1], Ewers, Frank [2], Davis, Stephen [3], Bobich, Edward [1].

Recovery of California black walnut trees following drought induced dieback.

Following several years of historic drought, the California black walnut (Juglans californica Wats.) was observed to dieback and resprout, apparently as a response to water stress. It has been previously studied for its ability to resprout after wildfire, in which fire resprouts had greater water status than nearby unburned adults. The goal of this study was to determine if drought resprouts exhibit advantages over the adult growth form, similar to fire resprouts. Drought resprouts and adult trees were sampled at the Frank G. Bonelli Regional Park in San Dimas, California, and Pepperdine University and Solstice Canyon in Malibu, California including through the dry seasons of 2017 and 2018. It was hypothesized that drought resprouts would have less negative water potentials than adults that did not die back, as a result of having less leaf area per root mass. It was also hypothesized that drought resprouts would have more negative water potentials than fire resprouts due to the environmental conditions they were exposed to. As predicted, drought resprouts had greater water potentials than adult trees, with the water potentials being more negative than previous fire resprouts. In addition, drought resprouts had greater rates of transpiration and photosynthesis. This suggests that drought resprouts experience water transport advantages similar to fire resprouts; however, the drought resprouts were not as well hydrated as previously examined fire resprouts. Lastly, at the Pepperdine University and Solstice Canyon sites the walnut trees were burned during the Woolsey Fire in November 2018 and the resulting fire resprouts are being tracked.

1 - California State Polytechnic University, Pomona, Biological Sciences, 3801 West Temple Ave, Pomona, CA, 91768, United States
2 - California State Polytechnic University, Pomona, Department Of Biology, 3801 West Temple Avenue, Pomona, CA, 91768, United States
3 - Pepperdine University, NATURAL SCIENCE DIV, 24255 Pacific Coast Highway, Malibu, CA, 90263, United States

Keywords:
walnut
drought
resprout
Fire.

Presentation Type: Oral Paper
Session: PHYS1, Physiology
Location: San Pedro 2/Starr Pass
Date: Monday, July 29th, 2019
Time: 11:00 AM
Number: PHYS1012
Abstract ID:623
Candidate for Awards:Physiological Section Physiological Section Li-COR Prize