Wastewater has become a vital new supply for irrigation; however, concerns are mounting about environmental and health hazards related to heavy metals present in wastewater. Experiments were conducted to evaluate wheat ( Triticum aestivum L.) and buckwheat (Fagopyrum esculentum L.) uptake of copper (Cu) and zinc (Zn). / Some 15 plants per pot were allowed to establish themselves in the greenhouse for 4 and 6 weeks for buckwheat and wheat, respectively. Plants were then transferred to one of two growth chambers differing in the vapor pressure deficit (VPD), creating conditions for two different transpiration rates to occur: high (HT) and low (LT). A total 48 pots for each crop were seeded in order to evaluate the effect of 8 treatment combinations of Cu and Zn (0/0, 5/0, 15/0, 30/0, 0/25, 5/25, 15/25, 30/25) levels (mg L-1). Treatments were laid out in a completely randomized design within each growth chamber. / Three plants were harvested from each pot at days 10 and 20 for wheat, and days 6, 12 and 18 days for buckwheat to measure dry mass and Cu and Zn content in different plant parts. Heavy metal treatments had no significant effect on transpiration rate for either crops. The higher transpiration rate increased Cu/Zn uptake. A Zn amendment in the absence of Cu had a beneficial effect on buckwheat growth, whereas with Cu at 15 mg Cu L-1 or 30 mg Cu L-1 the lowest dry weights were recorded, regardless of the transpiration rate. Roots contained greater concentrations of Cu and Zn, irrespective of the treatment level and transpiration rate, than did stems, leaves or grain. High retention of heavy metals in the roots of cereal crops may be desirable because these parts are not generally utilized as food or feed.

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