2017 ASHS Annual Conference

Cornus alba (tatarian dogwood) is a popular ornamental shrub with notable features including white fruit, yellowish white flower, and red stems in fall through late winter. A greenhouse experiment was conducted to characterize the morphological and physiological responses of tatarian dogwood to salinity stress. Tatarian dogwood seedlings grown in three growing media (Metro-Mix 360, Metro-Mix 560, Metro-Mix 902) were irrigated with nutrient solution at electrical conductivity (EC) of 1.2 dS∙m^-1 (control) or saline solution at EC of 5.0 or 10.0 dS∙m^-1 (EC 5 or EC 10) for eight times on a weekly basis. Results showed that the growing media did not influence C. alba growth. All plants of tatarian dogwood died in EC 10, whereas those in EC 5 exhibited moderate foliar damage. Compared to control, EC 5 reduced plant height and shoot dry weight by 37% and 21%, respectively. Significant reductions were also found in relative chlorophyll content (SPAD) reading, chlorophyll fluorescence (Fv/Fm), performance index (P_i), net photosynthesis (Pn) in plants in EC 5 and EC 10 treatments. Compared to control, leaf Na concentrations of tatarian dogwood in EC 5 and EC 10 increased 11 and 39 times, respectively, whereas leaf Cl concentrations increased 32 and 24 times, respectively. Based on growth and physiological responses to elevated salaintiy, we conclude that C. albais moderately salt sensitive.