Relative salt tolerance of eight
Berberis thunbergii(japanese barberry) cultivars ( B. thunbergiiCeleste, Kasia, Maria, Mini, and Talago; B. thunbergiivar. atropurpureaConcorde, Helmond Pillar, and Rose Glow) was evaluated in a greenhouse experiment. Plants were irrigated with nutrient solution at an electrical conductivity (EC) of 1.2 dSm1 (control) or saline solutions at an EC of 5.0 or 10.0 dSm1 (EC 5 or EC 10) once a week for 8 weeks. At 4 weeks after treatment, all barberry cultivars in EC 5 had minimal foliar damage with visual scores of 4 or greater (visual score 0: dead, 5: excellent). At 8 weeks after treatment, in EC 5, Helmond Pillar, Maria, Mini, and Rose Glow plants exhibited slight foliar salt damage with an average visual score of 3.5, whereas Celeste, Concorde, Kasia, and Talago had minimal foliar salt damage with an averaged visual score of 4.4. However, most barberry plants in EC 10 exhibited severe foliar salt damage 4 weeks after treatment with the exception of Concorde and were dead 8 weeks after treatment. Compared with control, at the end of the experiment (8 weeks of treatments), shoot dry weight (DW) of Celeste, Helmond Pillar, Maria, and Rose Glow in EC 5 was reduced by 47%, 47%, 50%, and 42%, respectively, whereas shoot DW of Concorde, Kasia, Mini, and Talago in EC 5 did not change. In EC 10, shoot DW of Celeste, Concorde, Kasia, and Talago was reduced by 75%, 35%, 55%, and 46%, respectively. The averaged sodium (Na) concentration of all barberry cultivars in EC 5 and EC 10 was 34 and 87 times, respectively, higher than the control, whereas leaf chloride (Cl) concentration of all barberry cultivars in EC 5 and EC 10 was 1460 and 29106 times, respectively, higher than the control. Growth, visual quality, and performance index (PI) were all negatively correlated with leaf Na and Cl content in all cultivars, suggesting that excessive Na and Cl accumulation in the leaf tissue led to growth reduction, salt damage, and death. In summary, Concorde, Kasia, and Talago were relatively salt tolerant; Helmond Pillar, Maria, Mini, and Rose Glow were relatively salt sensitive; and Celeste was in between the two groups. Generally, barberry plants had moderate salt tolerance and can be irrigated with marginal water at an EC of 5 dSm1 or lower with slight foliar damage.