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Harvard Forest REU Symposium Abstract 2018
- Title: Hydraulic Capacitance in Four Temperate Tree Species
- Author: Katja S Diaz-Granados (Harvard University)
- Abstract:
One of the ways in which plants mitigate hydraulic dysfunction is through transient water storage and release, a trait measured as hydraulic capacitance, or the amount of water that can be released per unit change in water potential or pressure. Water is stored in and around the transpirational stream of water, such that if the plant begins experiencing water stress, additional water can be released into the conducting vessels to prevent the water potential from fluctuating dangerously. Hydraulic capacitance is understood to be dependent on three sources of water, each of which corresponds to a separate phase when plotted as a water release curve. The first two of these, capillary spaces and elastic tissues, were studied using multi-year stems and current year stems taken from four tree species (Fagus grandifolia, Fraxinus americana, Quercus rubra and Acer rubrum) at the Harvard Forest Common Garden in Petersham, Massachusetts. By measuring water potentials using a thermocouple psychrometer and plotting these against water content, it was found that there was little difference between capacitance for tissue type. However, the reliance on capillary water versus water from elastic tissues appeared to differ at the species level, suggesting that the four species were employing different strategies for auxiliary water use.
- Research Category: Physiological Ecology, Population Dynamics, and Species Interactions
