Growth, Morphological, and Biochemical Responses of Four Native Species to Salinity Stress

Native plants are of great value in landscape maintenance. Despite their im-portance in the landscape, the salt tolerance of most native plants has received little attention. The present research was designed to assess morphological, physiological, and biochemical responses of four Utah-native plants [Arctostaphylos uva-ursi (kinni-kinnick), Cercocarpus ledifolius (curl-leaf mountain mahogany), Cercocarpus monta-nus 'Coy' (alder-leaf mountain mahogany), and Shepherdia xutahensis 'Torrey' (hybrid buffaloberry)] at different salinity levels. Each species was irrigated with a nutrient solution at an electrical conductivity (EC) of 1.2 dS center dot m-1 (control) or saline solutions at ECs of 5.0 or 10.0 dS center dot m-1 for 8 weeks. The experiment was a randomized complete block design with 10 replications. At 8 weeks after the initiation of the ex-periment, A. uva-ursi and C. montanus 'Coy' had slight foliar salt damage with an av-erage visual score of 3.7 (0 = dead, 5 = excellent with no sign of foliar salt damage) when irrigated with saline solution at an EC of 5.0 dS center dot m-1 and were dead at an EC of 10.0 dS center dot m-1. Similarly, C. ledifolius had an average visual score of 3.2 when irri-gated with saline solution at an EC of 10.0 dS center dot m-1. However, almost no foliar salt damage was observed on S. xutahensis 'Torrey' during the experimental period. In addition, the shoot dry weight of all species was reduced with elevated salinity levels in the irrigation water. Salinity stress also reduced gas exchange rates of plants and affected their mineral content. Proline accumulated in the leaves of native plants but was species-dependent. In conclusion, S. xutahensis 'Torrey' was tolerant to salinity stress followed by C. ledifolius; A. uva-ursi and C. montanus 'Coy' were sensitive to salinity stress.