Effects of copper sulfate on seedlings of Prosopsis pubescens (Screw bean mesquite)

Marian N. Zappala, University of Texas at El Paso
Joanne T. Ellzey, University of Texas at El Paso
Julia O. Bader, University of Texas at El Paso
Jose R. Peralta-Videa, University of Texas at El Paso
Jorge Gardea-Torresdey, University of Texas at El Paso


Phytoextraction is an established method of removal of heavy metals from contaminated soils worldwide. Phytoextractions is most efficient if local palnts are used in the contaminates site. We propose the Prosopis pubescens (Screw bean mesquite) would be a successful phytoextractor of coppe in our local soils. In order to determine the feasibility of using Screw bean mesquite for phytoremediation of desert soils, we utilized ion-coupled spectroscopy (ICP-OES) and elemental analysis to observe the uptake of copper and the effects on macro and micro nutrients within laboratory-grown seedlings. We have previously shown that Prosopis pubescens is a hyperaccumulator of copper in soil-grown seedlings. Light and transmission electron microscopy demonstrated the death of root cells and ultrastructural changes due to the presence of copper from 50 mg L-1-600 mg L-1. Ultrastructural changes included plasmolysis, starch accumulation, increased vacuolation and swollen chloroplasts with disarranged thylakoid membranes in cotyledons. We concluded that Prosopis pubescens is tolerant to copper with no macro or micro-nutrient changes when exposed to 200 mg L-1 or less of copper.