Comparative Leaf Hydraulics in Five Tree Species Growing in Urban and Rural Locations
Abstract
Urban habitats have a complex suite of abiotic factors including elevated temperatures, increased air pollution, elevated CO2, while impervious surface area and compacted soils decrease soil water availability. Studies have shown that urban trees have limited water availability and are more vulnerable to xylem cavitation (Savi et al. 2015). However, our understanding of hydraulic behavior in urban trees is still limited and very few studies have explored leaf hydraulic responses in urban settings. Leaves account for 30% of resistance in the whole-plant hydraulic pathway, thus leaf hydraulic conductance (Kleaf) is an important trait for understanding plant hydraulic behavior (Sack and Holbrook 2006). The purpose of this study was to quantify interspecific variation in leaf hydraulics for five tree species occurring in an urban and a rural site. Study sites consisted of Lakeview cemetery in Cleveland, Ohio and rural Secrest Arboretum in Wooster, Ohio. Maximum leaf hydraulic conductance was measured on three individuals per species at each location using the evaporative flux method. Additionally, turgor loss point was determined for each individual using a VAPRO osmometer. Trees at the rural location had more negative turgor loss points (TLP) than the urban location (F=8.71, p < .01). A lower TLP indicates a higher drought tolerance. Maximum Kleaf was significantly different between species with Liquidambar styraciflua having the highest values of Kleaf. For most species, Kleaf was higher in the urban location suggesting that they were either less water stressed or experienced a higher vapor pressure deficit, although these differences were only marginally significant (p = .057). NOAA climate data revealed that the average daily maximum temperature at the rural site was 27.5 °C with a low of 16 °C. Average temperatures at Lakeview were 27 and 18.6 °C. These data indicate that differences in overall climate and/or site-specific differences, rather than urban and rural factors, could be driving hydraulic differences between trees at the locations.
Literature Cited: Sack, L., and N. M. Holbrook. 2006. Leaf Hydraulics. Annual Review of Plant Biology 57:361-381. Savi, T., S. Bertuzzi, S. Branca, M. Tretiach, and A. Nardini. 2015. Drought-induced xylem cavitation and hydraulic deterioration: Risk factors for urban trees under climate change? New Phytologist 205:1106-1116.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B51I2048D
- Keywords:
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- 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCESDE: 0476 Plant ecology;
- BIOGEOSCIENCESDE: 1813 Eco-hydrology;
- HYDROLOGY