After 58days, Fe10 plants remained green (49238 mmol Chlm2)
but Fe0 plants were chlorotic (148 24 mmol Chl m2). At this
time point, plants were transferred individually to 1-L glass jars
that contained nutrient solution. Four Fe10 plants were grown
in the continued presence of 10 mM Fe and four Fe0 plants
were grown in the continued absence of Fe (positive and
negative controls, respectively). 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.