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HS-PLT29

Germination Characteristics and Metal Tolerance of Atriplex lentiformis and Atriplex canescens Seeds Under Zinc Stress

Plant Science
Maritza Roberts

Grade:
12
Teacher:
John-Paul Mann

ABSTRACT In the United States, 500,000 mines are abandoned, and 200,000 of the abandoned mines are found in Arizona (Bureau of Land Management). Abandoned mine tailing sites remain un-vegetated for decades due to low pH, high salinity, nutrient deficiencies, particularly low organic matter, and efflorescent salt erosion in the soil. Globally, 12 million tons of Zn mine tailings are produced, and 23 million people live in mine tailing danger zones, exposed to toxic waste everyday (Gill, 2023; Macklin et al. 2023). Tailing soil is then ingested as Zinc (Zn) particles, causing abdominal pain, nausea, vomiting, lethargy, anemia, brain cytotoxicity, and dizziness. A solution: tailings can be stabilized through phytostabilization applications, a bioremediation method which reduces heavy metal pollution by immobilizing metals in soil as plants create deep root networks. By testing Atriplex lentiformis (AL), AL mine site subpopulation, and Atriplex canescens (AC) for total % seed metal tolerance and total % seed germination, we can develop a novel understanding of native grown, Atriplex spp. metal stress thresholds during germination and early seed development. Both of these Atriplex spp. are native, halophytic, drought-tolerant shrubs from the Southwest; this makes these Atriplex spp. a potential, wide range, solution for tailing remediation of semi-arid desert ecosystem soil). Germination of AL and AC were tested at different Zn metal stress levels (100, 500, 1000, 2000, and 4000 ppm of Zn). Statistical significance was confirmed using student's T-Tests and two-way ANOVA with Tukey's HSD as a post hoc test. This research offers insight into the AL and AC seed’s metal sensitivity, and germination capacity under stress, while also pinpointing germination variance among species, subpopulations, and variable Zn concentrations (with no chemical pre-treatment, amended soils, or additional seedling growth nutrients). This remediation method using AL and AC is cost effective ($10-$35 USD/ton), introduces a native colonizing species to barren land, promotes ecological succession, and demonstrates Atriplex spp. resilience through genetic adaptability.


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One thought on “Germination Characteristics and Metal Tolerance of Atriplex lentiformis and Atriplex canescens Seeds Under Zinc Stress

  1. Outstanding work! You clearly communicated your research findings and the broader impacts. Very interesting results! Excellent job!

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