PROLINE ACCUMULATION IN WHEAT SEEDLINGS EXPOSED TO ZINC AND COPPER

The changes in proline level of wheat seedlings in response to Zn and Cu (10 ppm) treatment have been monitored. The proline content in shoots increased progressively with an increase in the length of time of exposure to metals (time course) as well as in a concentration-dependent manner (dose-response). Roots exhibited a fluctuating pattern of proline accumulation. Detached leaves also showed a rise in proline level, though of a lower magnitude than in intact seedlings, in response to applied metals. Copper proved to be a stronger inducer of proline accumulation than Zn and it was more toxic than Zn in terms of chlorophyll inhibition. The possibility of proline involvement in metal tolerance is suggested.