2021 journal article
Estimation of water stress tolerance of six woody plant species
Horticulture International Journal, 5(2), 64–72.
open access via medcraveonline.com (publisher PDF)
As climate change becomes even more prominent, urban plantings face many challenges (e.g., drought heat island effects, poor soil, high vapor pressure deficits). Therefore, proper plant selection is increasingly essential. Six commonly planted functional landscape plants (Callicarpa americana L., Cornus sericea L., Ilex verticillata Itea L., Rhus aromatica Aiton. and Cornus sanguinea L.) were grown in 3.8 L pots and put through a series of three dry down periods (August-October 2015) to analyze the drought tolerance and water use efficiency through the use of vapor pressure deficit (VPD). Evapotranspiration, growth data, and weather data were taken throughout the study. Maximum air temperature was 33.1 ⁰C and maximum VPD was 2.4 kPa over the course of the study. Growth data were influenced by species and drought resistance mechanisms. Cornus sanguinea and R. aromatica demonstrated the slowest water depletion rates, the greatest water use efficiency, and highest drought tolerance when compared to other species throughout the study. Water depletion rates and initial water use was greatest in C. americana and I. virginica across all dry down periods. Cornus sanguinea and R. aromatica are recommended for water-deficient urban landscapes while C. americana and I. virginica are not due to greater water depletion rates and decreased water use efficiency. The use of VPD to evaluate the drought tolerance of these woody species appears to effectively normalize water use rates and allow for the evaluation of species undergoing water stress.