Iron was resupplied to six Fe0 plants by two distinct treatments: (i) foliar spray (Fe-leaves), i.e.
plants grown in nutrient solution without Fe were sprayed
three times every two days with a solution of 1.8 mM Fe as ferrous sulphate (pH ¼ 5.34 0.01; EC ¼ 0.36 0.00 dS m1);
(ii) nutrient solution (Fe-solution), i.e. plants were transferred to
nutrient solution that contained 0.75 mM Fe as ferrous
sulphate. In the Fe-leaves treatment, all leaves (approximately
five) were sprayed on both the abaxial and adaxial surfaces;
a total volume of 83 mL (without a wetting agent or surfactant)
was applied to each plant over the course of the three sprays.
In conclusion, four treatments were conducted, each with at
least three plants (replicates): (1) plants always grown without
Fe (Fe0); (2) plants always grown with Fe (Fe10); (3) chlorotic
plants sprayed with Fe (Fe-leaves); (4) chlorotic plants transferred
to a solution that contained Fe (Fe-solution). For all in
the four treatments, plants were grown for nine days in the
same glasshouse.