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Harvard Forest REU Symposium Abstract 2008
- Title: Calcium deficiency and whole plant water relations in sugar maple (Acer saccharum Marsh.)
- Author: Lee H Dietterich (Harvard University)
- Abstract:
Calcium (Ca) is disappearing from forests in the northeastern United States and eastern Canada as a result of several anthropogenic causes. The depletion of Ca, a biologically essential element, is considered a causal factor in sugar maple decline and the diminishing health in general of many forests in this region. However, little is known about the physiological mechanisms by which decreased Ca availability affects forest growth and productivity. We tested the hypothesis that Ca depletion compromises the structure and function of plant conductive tissue, in particular stem xylem, pit membranes, and leaf conduits. We measured stem and leaf structure, hydraulic conductance, cavitation resistance, and leaf turgor loss point on samples of sugar maple (Acer saccharum Marsh.) grown in a long-term forest Ca-manipulation experiment. Preliminary visual observations suggested that Ca manipulation significantly affects forest health and productivity. However, we found no significant difference in any of the physiological properties that we measured between samples subjected to different Ca levels. This could indicate that Ca availability does not affect these properties, or that our sample size was too small to resolve the differences. Alternatively, because our sampling focused on healthy trees in order to identify potential causes of sugar maple decline, it is possible that the effects of differential Ca availability have a longer latency period and a more sudden onset than we expected. Future experiments might continue to monitor healthy maples but also examine declining trees to relate symptoms of decline to symptoms of Ca deficiency.
- Research Category: Physiological Ecology, Population Dynamics, and Species Interactions
