  We discuss the sensitivity of eta and eta' photoproduction near threshold to
the gluonic OZI breaking parameters in the U_A(1)-extended effective chiral
Lagrangian for low-energy QCD. Our coupled-channels analysis hints at a strong
correlation between the gluon-induced contributions to the eta' mass and the
low-energy pp -> pp eta' reaction and the near-threshold behaviour of the gamma
p -> eta p cross-section.
