Abstract/Summary

In a previous study we showed that Cistus albidus (L.) experiences an age‐dependent decay in flower vigour correlated with a decline in trans‐zeatin (tZ) levels. In the present study we aimed to establish a causal relationship between these two phenomena. Exogenous tZ applied to plants grown under semi‐controlled conditions did not rescue flower vigour; however, it accelerated flower development, but only in younger individuals. Older plants showed lower tocopherol levels in flower buds, which were restored by exogenous tZ, suggesting that a loss of antioxidant defences may underlie the age‐dependent decay in flower vigour. We conclude that declining tZ levels may not be directly responsible for the age‐associated loss of floral vigour; that tZ modulates the speed of flower development as plants age; and that flower buds alter their sensitivity to tZ as plants age.