The Fo values in the second maize crop were also smaller in the
leaves of plants grown in the reference soil, although they were greater
when 270mgZn kg−1were added,which resulted in smaller Fv/Fmand
Fv/Fo ratios, Y(II) and ETR. The Fv/Fo ratiowas also greater in the leaves
of plants from the reference soil. The greater values of the Fv/Fo ratio in
the soil with high Cu concentrations occurred with the addition of 0, 30
and 60 mg Zn kg−1. The NPQ valueswere smaller in the leaves of plants
grown in the soil supplementedwith 0, 30 and 60 mg Zn kg−1,whereas
qP showed no statistically significant difference.