[Physiological responses of cucumber seedlings grafted on different salt-tolerant rootstocks to NaCI stress].

Based on the salt-tolerance identification of a series of cucumber rootstock varieties, the cucumber cultivar 'Xintaimici' grafted on different salt-tolerant rootstock varieties 'Sherpa', 'Shintosa' , 'Tielizhen' , and 'Figleaf gourd' was selected to study its seedlings physiological responses to NaCl stress, taking the self-rooted ones as the control. Under the stress of 100 mmol NaCl x L(-1), the leaf electrolyte leakage rate and malondialdehyde (MDA) content of the grafted seedlings were significantly lower than those of self-rooted seedlings, and the seedlings grafted on 'Figleaf gourd' showed the lowest electrolyte leakage rate and malondialdehyde (MDA) content, followed by the seedlings grafted on 'Tielizhen', 'Shintosa' , and 'Sherpa'. The leaf proline and soluble sugar contents and peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities of the grafted seedlings were significantly higher than those of the self-rooted seedlings, and the POD, SOD, CAT, and APX activities were the highest for the seedlings grafted on 'Figleaf gourd' and the lowest for the seedlings grafted on 'Sherpa', but had no significant differences for the seedlings grafted on 'Tielizhen' and 'Shintosa'. The leaf Na+ content of the seedlings grafted on different rootstock varieties ranked as 'Figleaf gourd' < 'Tielizhen' < 'Shintosa' < 'Sherpa', while the leaf K+ content had little difference for the seedlings grafted on 'Figleaf gourd', 'Tielizhen', and 'Shintosa' but was significantly higher than that for the seedlings grafted on 'Sherpa'. The self-rooted seedlings had the highest leaf Na+ content but the lowest leaf K+ content. The leaf Na+/K+ ratio of grafted seedlings was significantly lower than that of self-rooted ones, and the seedlings grafted on 'Figleaf gourd' had the lowest leaf Na+/K+ ratio.