Physiological and biochemical responses of Brassica napus L. cultivars exposed to Cd stress

Four different rapeseed (Brassica napus L.) cultivars CZL, Benefit, Iwas and ZhongZhuang9, were used to analyse physiological responses to higher doses of cadmium (Cd) and their ability of Cd accumulation. Plants were exposed for 30 days to different Cd dosages (0, 50, 100, and 150 mg Cd/kg) in soil under greenhouse conditions. Cad-mium was accumulated more in roots than in shoots of all tested cultivars, with the highest Cd in ZhongZhuang9. After the lowest Cd dose, the highest translocation factor was for CZL (0.8) and Benefit (0.6). The content of both K and Ca varied between treatments and cultivars. The chlorophyll fluorescence parameters and relative chlorophyll content were affected minimally. High constant levels of salicylic acid and a sharp increase in proline content were found mostly in Iwas; therefore, it may be considered as a more tolerant cultivar.