Effect of salicylic acid and sodium nitroprusside on growth and essential elements content in spring canola seedlings cv. PF under nickel stress

This research was performed in order to investigate the effect of salicylic acid and sodium nitroprusside on growth and essential elements content in spring canola under nickel stress in laboratory of Science and Research Branch, Islamic Azad University of Tehran. The interactive effects of nickel, salicylic acid (SA) and sodium nitroprusside (SNP) as a donor of nitric oxide (NO) were examined on canola (Brassica napus L. cv. PF) growth. 21-day old canola seedlings (cv. PF) were exposed to different concentrations of NiCl2, 6H2O (0, 0.5 mM), SA (0, 0.2 mM) and SNP (0, 0.2 mM) for 10 days. Nickel toxicity symptoms such as chlorosis and necrosis were observed on leaves of Ni-treated seedlings. Treatment with Ni resulted in a decrease in fresh and dry weight of roots and shoots. Mineral elements content (Mg, Fe, Ca, P, K) extremely decreased in roots and shoots of Ni-stressed canola seedlings, while the content of N in these seedlings increased in roots and decreased in shoots. Ni was more accumulated in roots than in shoots. In Ni-stressed seedlings, application of SA or NO, especially SA+NO, improved the growth and decreased the toxicity symptoms as compared to Ni-treated seedlings. SA or NO, especially both together, considerably reduced root-to-shoot translocation of Ni and increased the content of mineral elements in roots and shoots of Ni-stressed seedlings. These results showed that SA or NO and in particular their combination, markedly reduced the toxic effects of nickel on canola seedlings by sequestration of Ni in roots and amelioration of mineral nutrition.