Review lecture - Hormones in healthy and diseased plants

The hormones known to be responsible for control of many aspects of plant growth and development are first briefly described. The effects of infection of plants by certain biotrophic parasites on hormone metabolism and function are then discussed, together with the associated developmental abnormalities. It is seen that though disease frequently does cause considerable changes in hormone levels, the reasons for these changes have only in very few cases been determined. Attention is drawn to the fact that toxins produced by biotrophic parasites may have hormone-like effects, though structurally unrelated to any known endogenous plant hormone.