Underlying Carbon-Water Transport Mechanisms
The plant vascular system transports water from the soil into the atmosphere and distributes assimilated carbon, as carbohydrates, throughout the plant. These carbohydrate and hydraulic systems are, thus, adapted to function within the typical range of local climatic variability. Rising temperatures and changing precipitation, however, are pushing plant carbohydrate and hydraulic systems into anomalous operating conditions, often resulting in temporary or permanent physiological damage. One line of my research combines computational statistics and ecophysiological techniques to examine the mechanisms underlying plant vascular recovery in response to extreme climatic events. Up to this point, I have primarily focused on natural and agricultural plants found in California, such as coastal redwood, Sierra Nevada conifer species, walnut, pistachio, and almond. For instance, we were the first to demonstrate that coastal redwood utilizes water absorbed through its bark during fog/rain events to recover from drought stress (Earles et al, 2016; Fig. 1). We also discovered that winter frost and warming cycles deplete stored carbohydrates across numerous natural and agricultural species, a previously undescribed mechanism (Sperling et al., 2015; Fig. 2). During California’s extreme drought from 2011-2015, we observed that extreme mid-winter drought can actually weaken tree hydraulic and carbohydrate systems (Earles et al., in review; Fig. 3). In other studies, we investigated the basic carbon-water transport mechanisms fueling spring bud growth in walnut (Tixier et al., 2017; Fig. 4) and the capacity for laurel to recover vascular transport following drought-stress (Knipfer et al., in review; Fig. 5).
Craig Brodersen – Yale University
Italo Cuneo – Pontificia Universidad Católica de Valparaíso, Chile
Matthew Gilbert – University of California, Davis
Jessie Godfrey – University of California, Davis
Thorsten Knipfer – University of California, Davis
Bruce Lampinen – University of California, Extension
Andrew McElrone – USDA Agricultural Research Service
Malcolm North – US Forest Service
Jessica Orozco – University of California, Davis
Clarissa Reyes – University of California, Davis
Adele Roxas – University of Palermo, Italy
Sebastian Saa – University of California, Davis
Francesca Secchi – University of Torino, Italy
Lucas Silva – University of Oregon
Or Sperling – Israel Agricultural Research Organization, Volcani Center
Jens Stevens – University of California, Berkeley
Aude Tixier – University of California, Davis
Maciej Zwieniecki – University of California, Davis
Earles, J.M., Stevens, J.T., Sperling, O., North, M., and Zwieniecki, M. (in review). Extreme mid-winter drought weakens tree hydraulic and carbohydrate systems.
Knipfer, T., Cuneo, I.F., Earles, J.M., Reyes, C., Brodersen C.R., and McElrone, A.J. (in review). Storage compartments for capillary water refill in excised stems but rarely in intact plants (Laurus nobilis): In-situ visualization of tissue-specific dynamics.
Tixier, A., Sperling, O., Lampinen, B., Roxas, A., Saa, S., Earles, J.M., Orozco, J., and Zwieniecki, M. (2017). Spring bud growth depends on sugar delivery by xylem and water recirculation by phloem Münch flow in Juglans regia. Planta, 246(3): 495-508.
Earles, J.M., Sperling, O., Silva, L., North, M., and Zwieniecki, M. (2016). Bark water uptake promotes localized hydraulic recovery in branches of coastal redwood. Plant, Cell and Environment, 39: 320-328.
Sperling, O., Earles, J.M., Secchi, F., Godfrey, J. and Zwieniecki, M. (2015). Frost induces respiration and accelerates carbon depletion in trees. PLOS One.