Iron Toxicity
Iron toxicity is not a common problem in the field, except in rice crops in Asia
(29). It can also occur
in pot experiments, and in cases of oversupply of iron salts to ornamental plants such as azaleas.
The symptoms in rice, known as ‘Akagare I’ or ‘bronzing’ in Asia, include small reddish-brown
spots on the leaves, which gradually extend to the older leaves. The whole leaf may turn brown, and
the older leaves may die prematurely
(29). In other species, leaves may become darker in color and
roots may turn brown
(29). In rice, iron toxicity seems to occur above 500 mg Fe kg
-1 leaf dry
weight
(30) (Figure 11.5).
 |
| FIGURE 11.5 Symptoms of iron toxicity in lowland rice (Oryza sativa L.) in Sri Lanka as a consequence of
decreased redox potential under submergence. |
