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

Joseph K Sagers,Joseph Earl Creech,Ivan W Mott,Bruce Bugbee,Blair L Waldron

doi:10.1002/ece3.3607

Joseph K Sagers, Joseph Earl Creech + Show 3 more

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https://doi.org/10.1002/ece3.3607

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Abstract

Halogeton (Halogeton glomeratus) is an invasive species that displaces Gardner's saltbush (Atriplex gardneri) on saline rangelands, whereas, forage kochia (Bassia prostrata) potentially can rehabilitate these ecosystems. Salinity tolerance has been hypothesized as the predominant factor affecting frequency of these species. This study compared relative salinity tolerance of these species, and tall wheatgrass (Thinopyrum ponticum) and alfalfa (Medicago sativa). Plants were evaluated in hydroponics, eliminating the confounding effects of drought, for 28 days at 0, 150, 200, 300, 400, 600, and 800 mmol/L NaCl. Survival, growth, and ion accumulation were determined. Alfalfa and tall wheatgrass shoot mass were reduced to 32% of the control at 150 mmol/L. Forage kochia survived to 600 mmol/L, but mass was reduced at all salinity levels. Halogeton and Gardner's saltbush increased or maintained shoot mass up to 400 mmol/L. Furthermore, both actively accumulated sodium in shoots, indicating that Na+ was the principle ion in osmotic adjustment, whereas, forage kochia exhibited passive (linear) Na+ accumulation as salinity increased. This study confirmed the halophytic nature of these three species, but, moreover, discovered that Gardner's saltbush was as saline tolerant as halogeton, whereas, forage kochia was less tolerant. Therefore, factors other than salinity tolerance drive these species’ differential persistence in saline‐desert ecosystems.

Highlights

Gardner’s saltbush (Atriplex gardneri) is an indigenous perennial shrub in the salt desert shrub ecosystems of the western USA, where it is a valuable source of feed for livestock and wildlife (Smith, Waldron, Creech, Zobell, & Zobell, 2016)
Based upon growth is reduced by 50% (GR50) values for shoot mass (Tables 1–3), the salt tolerance of these species would be ranked in this order: Gardner’s saltbush = halogeton > forage kochia (Immigrant > Snowstorm) > alfalfa > tall wheatgrass
It is remarkable that alfalfa would be reported to have greater salt tolerance than tall wheatgrass, and, based upon these measurements, it was equal in salt tolerance to Snowstorm forage kochia

Summary

| INTRODUCTION

Gardner’s saltbush (Atriplex gardneri) is an indigenous perennial shrub in the salt desert shrub ecosystems of the western USA, where it is a valuable source of feed for livestock and wildlife (Smith, Waldron, Creech, Zobell, & Zobell, 2016). The objectives of this study were to: (1) document the comparative salinity tolerance of halogeton, Gardner’s saltbush, and forage kochia, and; (2) to determine and/or verify if these species are halophytes by defining their growth and ion accumulation response to increasing levels of salinity. By conducting this trial in a hydroponic environment, comparisons of response to salinity were made between species, without the confounding effect of drought tolerance or limited nutrients. Documenting the relative salinity tolerance helps elucidate the competitive interactions occurring between these species on sensitive and transitional saline rangelands

| METHODS

| DISCUSSION

| Conclusions about comparative salt tolerance

| CONCLUSIONS

Findings

CONFLICT OF INTEREST