Salinity tolerance of three competing rangeland plant species: Studies in hydroponic culture

Authors: SAGERS, JOSEPH - Utah State University; Waldron, Blair; CREECH, J - Utah State University; Mott, Ivan; BUGBEE, BRUCE - Utah State University

Submitted to: Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2017
Publication Date: 11/12/2017
Citation: Sagers, J.K., Waldron, B.L., Creech, J.E., Mott, I.W., Bugbee, B. 2017. Salinity tolerance of three competing rangeland plant species: Studies in hydroponic culture. Ecology and Evolution. 7:10916-10929. https://doi.org/10.1002/ece3.3607.
DOI: https://doi.org/10.1002/ece3.3607

Interpretive Summary: Halogeton (Halogeton glomeratus) is an invasive species that displaces Gardner's saltbush (Atriplex gardneri) on saline rangelands. Forage kochia (Bassia prostrata) is a potential species to rehabilitate these ecosystems. This study compared the salinity tolerance of these species to tall wheatgrass (Thinopyrum ponticum) and alfalfa (Medicago sativa). Plants were evaluated for 28 days in hydroponics, where they were maintained at 0, 150, 200, 300, 400, 600, and 800 mM NaC1. Shoot growth and sodium accumulation were determined. Salt tolerance ranking, based on 50% shoot reduction, was Gardner's saltbush=halogeton>forage kochia>alfalfa>tall wheatgrass. Both halogeton and Gardner's saltbush rapidly accumulated sodium in shoots even at low levels of salt. In contrast, forage kochia exhibited gradual uptake of sodium as salinity increased. This study confirmed that halogeton is a halophytic (salt loving) species. Moreover, Gardner's saltbush, also a halophyte, was equally salt tolerant, suggesting other factors are likely responsible for halogeton displacement of Gardner's saltbush on saline-desert ecosystems. Forage kochia is a halophytic species that can survive salinity equal to seawater, but is not as salt tolerant as Gardner's saltbush and halogeton.

Technical Abstract: Halogeton (Halogeton glomeratus) is an invasive species that displaces Gardner's saltbush (Atriplex gardneri) on saline rangelands. Forage kochia (Bassia prostrata) is a potential species to rehabilitate these ecosystems. This study compared the salinity tolerance of these species to tall wheatgrass (Thinopyrum ponticum) and alfalfa (Medicago sativa). Plants were evaluated for 28 days in hydroponics, where they were maintained at 0, 150, 200, 300, 400, 600, and 800 mM NaC1. Shoot growth and ion accumulation were determined. Alfalfa and tall wheatgrass were severely affected by salt with shoot mass reduced to 32% of the control at 150 mM NaC1. In contrast, forage kochia survived to 600 mM, but produced little shoot mass at that level. Halogeton exhibited 'halophytic' shoot growth, reaching maximum mass at 141 mM, and similar mass as the control until 400 mM. Gardner's saltbush growth was not affected up to 300 mM. Salt tolerance ranking, based on 50% shoot reduction, was Gardner's saltbush=halogeton>forage kochia>alfalfa>tall wheatgrass. Both halogeton and Gardner's saltbush actively accumulated sodium in shoots, indicating that Na+ was the principle ion in osmotic adjustment. In contrast, forage kochia exhibited passive (linear) uptake of Na+ accumulation as salinity increased. This study confirmed that halogeton is a halophytic species. Moreover, Gardner's saltbush, also a halophyte, was equally salt tolerant, suggesting other factors are likely responsible for halogeton displacement of Gardner's saltbush on saline-desert ecosystems. Forage kochia is a halophytic species that can survive salinity equal to seawater, but is not as salt tolerant as Gardner's saltbush and halogeton.