Figure 4

Inhibition of surface film growth, but not tendril growth, occurs if either FeSO ₄ or MnSO ₄ 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.