Document: JOY-3-32-33

Gender-specific responses of boxelder to water availability during a decade of growth in a common garden.

WARD, J.K.* ¹, T.E.DAWSON ², D.L.PIERCE ¹ and J.R.EHLERINGER ¹

University of Utah, Salt Lake City, UT, U.S.A. ¹
UC Berkeley, Berkeley, CA, U.S.A. ²

Abstract:
Understanding the effects of water availability on the population structure of riparian trees is critical for predicting the impact of climate change on riparian systems. Dioecious boxelder (Acer negundo) is a common riparian species that we are using as a sensitive indicator of water stress among riparian trees. From earlier studies,we know that the genders of boxelder respond differently to water availability in the field, where males were more conservative in their water use than females. We now extend earlier studies to include stable carbon isotope ratio analyses of alpha-cellulose and the widths of individual tree rings for male and female trees throughout a decade of growth in a common garden. Stable carbon isotope analyses that are currently being conducted will indicate whether or not the genders exhibit differential stomatal control over water loss during a major portion of their life cycle. In terms of growth, it was found that the width of tree rings was highly affected by year, but there were no significant differences between the tree ring widths of male and female trees, nor was there a significant year by gender interaction. This result indicates that throughout variable years of water availability, male and female boxelder exhibit similar growth responses despite possible differences in physiological responses to water availability.

Keywords: boxelder, gender responses, water relations, stable carbon isotopes, riparian ecology

This abstract is being presented at: 2:30 PM in session:
Oral Session #34: Water Relations in Trees.