Presentation Title

Salinity Responses of the Desert Shrubs Isocoma acradenia and Larrea tridentata

Faculty Mentor

Schenk, JH., Burnaford, JL., Hoese, WJ

Start Date

23-11-2019 10:00 AM

End Date

23-11-2019 10:45 AM

Location

85

Session

poster 3

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Saline soils can inhibit or even prohibit the growth of plants via ion toxicity and osmotic stress. Due to the preponderance of salts in arid soils, deserts are excellent places for studying how plants cope with salt stress. We investigated the salinity responses of two desert shrubs, Isocoma acradenia and Larrea tridentata, on a slope adjacent to Soda Dry Lake in the Mojave Desert, California. We hypothesized that ion concentrations in these shrubs would be related to the salinity of the surrounding soil. We collected predawn plant and soil samples in 30-40 meter intervals along a belt transect moving upslope from the dry lakebed and measured soil conductance and ion concentration in xylem sap and leaves. Conductance was higher in soil associated with Isocoma (mean ± SE: 5447.50 ± 5038.75 µS/cm) than with Larrea (mean ± SE: 90.63 ± 23.13 µS/cm). Isocoma leaves contained more sodium (mean ± SE: 549.19 ± 19.94 mmol/kg) than potassium (mean ± SE: 133.73 ± 18.75 mmol/kg), and Larrea leaves maintained similar amounts of sodium (mean ± SE: 119.28 ± 17.98 mmol/kg) and potassium (mean ± SE: 114.36 ± 41.83 mmol/kg). Trends were similar in xylem sap, with Isocoma having higher levels of both ions than Larrea. Disparities in tissue ion concentration and associated soil conductance were observed between the species even where distributions overlapped. Isocoma may concentrate sodium in leaves or excrete it. There are no previously described salt-excreting members of Asteraceae, and if Isocoma can be confirmed as such, it will be a new discovery.

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Nov 23rd, 10:00 AM Nov 23rd, 10:45 AM

Salinity Responses of the Desert Shrubs Isocoma acradenia and Larrea tridentata

85

Saline soils can inhibit or even prohibit the growth of plants via ion toxicity and osmotic stress. Due to the preponderance of salts in arid soils, deserts are excellent places for studying how plants cope with salt stress. We investigated the salinity responses of two desert shrubs, Isocoma acradenia and Larrea tridentata, on a slope adjacent to Soda Dry Lake in the Mojave Desert, California. We hypothesized that ion concentrations in these shrubs would be related to the salinity of the surrounding soil. We collected predawn plant and soil samples in 30-40 meter intervals along a belt transect moving upslope from the dry lakebed and measured soil conductance and ion concentration in xylem sap and leaves. Conductance was higher in soil associated with Isocoma (mean ± SE: 5447.50 ± 5038.75 µS/cm) than with Larrea (mean ± SE: 90.63 ± 23.13 µS/cm). Isocoma leaves contained more sodium (mean ± SE: 549.19 ± 19.94 mmol/kg) than potassium (mean ± SE: 133.73 ± 18.75 mmol/kg), and Larrea leaves maintained similar amounts of sodium (mean ± SE: 119.28 ± 17.98 mmol/kg) and potassium (mean ± SE: 114.36 ± 41.83 mmol/kg). Trends were similar in xylem sap, with Isocoma having higher levels of both ions than Larrea. Disparities in tissue ion concentration and associated soil conductance were observed between the species even where distributions overlapped. Isocoma may concentrate sodium in leaves or excrete it. There are no previously described salt-excreting members of Asteraceae, and if Isocoma can be confirmed as such, it will be a new discovery.