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Harvard Forest REU Symposium Abstract 2018

• Title: Water access and silica uptake in Acer rubrum, Fagus grandifolia, and Castanea dentata
• Author: Emory C Ellis (Hampshire College)
• Abstract:

  The importance of the terrestrial silica cycling in regulating watershed silica export is an emerging research topic. Of particular interest is the role environmental stressors may play in altering plant silica uptake in the growing season and release during senesce. Silica is taken up by plants as a mechanism to combat both abiotic and biotic stressors. Of particular interest is the role of silica uptake in combatting water stress (e.g., drought). To date, most research on drought has been conducted on crop plants. However, forested ecosystems are known to be “hot spots” of silica cycling – mining it from soils and groundwater and depositing in their tissue. Here we examined the impact of water stress on silica uptake in three species: Acer rubrum (Red maple), Fagus grandifolia (American Beech), and Castanea dentata (American chestnut). We hypothesized that the water stressed trees would take up more silica as a way to preserve cellular structure and maintain photosynthesis as found in research on crop plants. To test this hypothesis we measured biogenic silica concentrations in tree foliage weekly over a six week period. Additionally, we quantified readily dissolvable silica from xylem and phloem as a way to estimate silica movement in the trees. If we observe higher concentrations in the water stressed trees then we would have preliminary evidence that trees, like crop plants, take up silica as a mechanism for drought resistance. Ultimately, this study will help further our understanding of silica cycling in forested ecosystems.

• Research Category: Physiological Ecology, Population Dynamics, and Species Interactions; Watershed Ecology