Inhibition of surface film growth, but not tendril growth, occurs if either FeSO
is limiting. In this experiment, replicated independently, MSggN plates (5 mM KCl) were prepared with the normal levels of FeSO4 or MnSO4 (50 μM), or with the decreased levels of FeSO4 or MnSO4 indicated. Plates were inoculated with the hag strain and photographed after 24 h growth at 37°C. The level of agarose in the MSggN plates with MnSO4 was raised to 0.4% w/v (normally 0.3% w/v) to accentuate the details of the tendrils.