Copper Tolerance to Germination in Mesquite, a Potential Tree Species for Restoring Mined-lands in Oman

Prosopis juliflora (Sw.) DC. (Fabaceae Mimosoideae), commonly known as Ghaf Bahri or Velvet Mesquite, an introduced exotic tree species in Oman is considered as a noxious weed. Efforts to contain this tree are labor intensive and expensive. Therefore, an efficient use of this species for socioeconomic and environmental benefits in Oman must be considered seriously. This study initiates a feasibility investigation of using P. juliflora for the restoration of copper mined lands in Oman by evaluating copper tolerance to seed germination in the laboratory. Continuous exposure experiments showed the ability of P. juliflora to germinate in copper concentrations ranging from 10-1280 ppm. The adverse effect of copper on percentage seed germination was more pronounced in the first two days. From 3-8 days, P. juliflora showed a remarkable ability for recovery. Seedling morphology showed the adverse effect of copper exposure from 80 –1280 ppm and seedling height decreased exponentially with the increase in copper concentrations. The relationship between copper concentrations and the average copper content of the seedlings fits a non-linear power model. Thus the germinating seeds of P. juliflora also seem to serve as a sink for copper in contaminated soils. These ex situ germination experiments suggest that P. juliflora is a suitable species for use in the restoration of copper mined-lands. Using known facts, identifying both ecosystem and socioeconomic factors, a SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis is provided here to assist in recommending management strategies and policy decisions.