The relationship between metal toxicity and cellular redox imbalance.

The relationship between cellular redox imbalances leading to oxidative stress and metal toxicity in plants has been studied intensely over the past decades. This interdependency was often considered to reflect a rather indirect metal effect of cellular disregulation and progressive secondary damage development. By contrast, recent experiments revealed a clear relationship between metal stress and redox homeostasis and antioxidant capacity. Analysis of plants expressing targeted modifications of components of the antioxidant system, the comparison of closely related plant species with different degrees of toxic metal sensitivity and effector studies with, for instance, salicylic acid have established a link between the degree of plant tolerance to metals and the level of antioxidants.