INDUCING SALT TOLERANCE IN CANOLA (BRASSICA NAPUS L.) BY EXOGENOUS APPLICATION OF GLYCINEBETAINE AND PROLINE: RESPONSE AT THE INITIAL GROWTH STAGES

In order to assess whether exogenous application of glycinebetaine and proline could induce salt tolerance in canola, two canola cultivars Dunkled (salt tolerant) and Cyclone (salt sensitive) were allowed to germinate and grow at 0, and 120 mM NaCl for two weeks. Varying concentrations (0, 0.1, 0.5, 1 and 5 mM) of glycinebetaine (GB) or proline were applied through the rooting medium to non-stressed and salt stressed germinating seeds. Salt stress caused a marked inhibitory effect on germination and seedling growth of both canola cultivars. This adverse effect of salt stress on seed germination percentage was more on cv. Cyclone than on cv. Dunkeld. Exogenously applied GB and proline alleviated the adverse effects of salt stress on seed germination of both canola cultivars. Moreover, salt-induced reduction in seedling growth of both canola cultivars was counteracted by high concentration of GB (1 or 5 mM GB) added to the growth medium. Similarly, considerable growth improvement in salinized seedlings of both canola cultivars was observed when 1 or 5 mM proline was added to the growth medium.