Ion transport in four canola cultivars as influenced by salt stress

In order to assess relationship between ion transport and variation in growth responses of four canola cultivars under salt Stress, four canola cultivars were grown at 0 and 150 mM NaCl for six weeks in hydroponics. Salt stress reduced the shoot and root fresh and dry weights of all canola cultivars. Maximum shoot fresh and dry weights were recorded in Dunkeld under both non-saline and saline conditions, while cv. Cyclone had the minimum shoot and root fresh and dry weights of all cultivars examined under both stress and non-stress conditions. On the basis of growth of canola cultivars under salt stress Dunkeld was found to be salt tolerant, CON-III and Rainbow intermediate and Cyclone as salt sensitive cultivar. Transport of Na+ and Cl- were increased due to salt stress with a decrease in K+ and Ca2+ transport in all canola cultivars but transport of cations (Na+, K+, and Ca2+) decreased consistently over time. Furthermore, salt tolerant Dunkeld had the highest K+ and Ca2+ transports with a minimum Na+ transport to the leaves under saline conditions. Cl- transport remained almost unchanged over time under both non-saline and saline conditions, These results suggested that salt tolerant Dunkeld might have a key mechanism of ion exclusion and/or transport-restriction between the shoot and root to depress the transport of Na+ and Cl- to the upper plant parts, enabling a higher tolerance to NaCl.