The effects of NaCl priming on salt tolerance in canola (Brassica napus L.) seedlings grown under saline conditions

Seeds of canola (Brassica napus) cultivars “Hayola401” and “Zarfam” were primed with 14 dS m⁻¹ NaCl solution for 24 hours at 20°C. After priming, non-primed (NP) and primed (P) seeds were sown in germination boxes containing perlite. The germination boxes were placed in greenhouse and treated with five different NaCl solutions (0.4 (control), 4, 8, 12 and 16 dS m⁻¹), for a period of 3 weeks. Total emergence and dry weight were higher in canola seedlings derived from P seeds and they emerged earlier than NP seeds. Moreover, seeds from NP groups could tolerate up to 8 dS m⁻¹ NaCl salinity, while the total emergence values of P groups in “Hayola401” and “Zarfam” did not decrease below 50% at 12 and 16 dS m⁻¹, respectively. NaCl priming enhanced proline accumulation and prevented toxic and nutrient deficiency effects of salinity because less Na⁺ but more K⁺ and especially Ca²⁺ was accumulated in canola seedlings. As a matter of fact, Na: Ca²⁺ balances of seedlings derived from P seeds were significantly lower than those of NP seeds under similar salinity levels.