Effects of Exogenous Hydrogen Peroxide on Germination Characteristics of Cucumber Seeds under NaHCO3 Stress

The germination characteristics of cucumber seeds were determined after treatments of as follows: (1) the control (CK): distilled water; (2) Na: 70 mmol·L^-1 NaHCO₃; (3) H₁ + Na: 0.001 mmol·L^-1 H₂O₂ + 70 mmol·L^-1 NaHCO₃; (4) H₂ + Na: 0.01 mmol·L^-1 H₂O₂ + 70 mmol·L^-1 NaHCO₃. The results showed that the germination rate, germination potential, germination index, growing vigor index, the length of taproot, number of fist later root, the length of hypocotyledonary axis and fresh weight of cucumber under NaHCO₃ stress were decreased significantly, while these above indexes were markedly improved when exogenous H₂O₂ was added, compared to those under NaHCO₃ stress, which suggested that exogenous H₂O₂ enhanced cucumber seeds salinity tolerance. The result of subordination function showed that exogenous H₂O₂ had promoted the seeds germination under NaHCO₃ stress and the 0.001 mmol·L^-1 H₂O₂ concentration was the better treatment concentration in this study.