Evaluation of Phytoremediation Potential of Barbados Nut Grown in Cadmium-Contaminated Soil under Different Irrigation Regimes

Cadmium (Cd) is a widespread and toxic heavy metal that is a threat to plant, animal and human health.Phytoremediation, the use of tolerant species for the remediation of polluted areas, is a green technology that can be used for environmental pollution control.This pot study was conducted to evaluate the effect of soil Cd on growth, irrigation-water use efficiency, and Cd uptake, translocation and accumulation in Barbados nut under different irrigation regimes.Barbados nut was grown at low (50 mg kg -1 ), medium (100 mg kg -1 ) and high (200 mg kg -1 ) Cd levels as well as with no Cd under four irrigation regimes: 30, 50, 70 and 90% of soil water-holding capacity (SWC).Moreover 50% soil saturation percentage was considered as 100% SWC.The results revealed that the growth and dry matter accumulation of Barbados nut decreased with increasing soil Cd levels; however, this decrease declined with increasing irrigation amounts.In addition, Cd accumulation in different tissues was found to be in the order of root > stem > leaf, and excess soil Cd supply might inhibit Cd transportation from root to canopy.The higher dry matter accumulation, Cd accumulation, bioconcentration factor and irrigation-water use efficiency were observed at 50~70% SWC and low Cd levels (50 mg kg -1 ).Moreover, Barbados nut survived under severe drought (30% SWC) and the highest soil Cd concentrations (200 mg kg -1 ), exhibiting a strong capacity to resist drought and Cd stress.In conclusion, Barbados nut plants can be used for the phytoremediation of Cd-polluted soils in arid regions