2019 ASHS Annual Conference

Triston Hooks¹ and Genhua Niu¹

¹Texas A&M AgriLife Research, 1380 A&M Circle, El Paso, TX 79927; triston.hooks@ag.tamu.edu; genhua.niu@ag.tamu.edu

Abstract

Salt tolerant ornamental plants can be irrigated with low quality saline irrigation water for sustainable landscaping in arid and semi-arid regions. However, little attention has been devoted to evaluating salt tolerance in ornamentals. An eight-week greenhouse experiment was conducted to assess the relative salt tolerance of four perennial ornamentals, ‘Angelina’ (Sedum rupestre), ‘Autumn Joy’ (S. telephium), ‘Blue Spruce’ (S. reflexum), and ‘Blue Daze’ (Evolvulus glomeratus). The plants were grown in pots with potting mix substrate and irrigated with control or saline solutions. The electrical conductivity (EC) of the saline solutions were 5.0 and 10.0 mS/cm. Data collected included relative shoot, root, and total dry weight (DW), visual score, shoot tissue concentrations of Na⁺, Cl^-, K⁺, and Ca²⁺, and the K⁺/Na⁺ ratio. There were significant differences in treatment and varieties for all response variables, and some interactions were also significant indicating different responses to salinity from the four varieties. Shoot, root, and total DW decreased with increasing salinity for all varieties and shoot growth appeared to be more sensitive to root growth only in Angelina and Blue Daze when treated with EC5. Visual score was highest in Autumn Joy and Blue Spruce when treated with EC5 and EC10 and lowest in Angelina and Blue Daze, the latter of which showed symptoms of moderate foliar damage including leaf necrosis, or “burn”, due to salt. The concentrations of Na⁺ and Cl^- in the shoot tissue increased with increasing salinity while K⁺ and Ca²⁺ and the K⁺/Na⁺ ratio tended to decrease. Autumn Joy had the lowest concentrations of Na⁺ in the shoot tissue and the highest K⁺/Na⁺ ratio. Blue Daze had the lowest concentrations of Cl^-, K⁺, and Ca²⁺ and the lowest K⁺/Na⁺ ratio. Of the four varieties of ornamental plants evaluated in this study, Autumn Joy and Blue Spruce were considered the most relatively salt tolerant while Angelina and Blue Daze were considered less tolerant.

Acknowledgments

This research was funded by the USDA-ARS Floriculture and Nursery Research Initiative