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 center dot L-1 NaHCO3; (3) H-1 + Na: 0.001 mmol center dot L-1 H2O2 + 70 mmol center dot L-1 NaHCO3; (4) H-2 + Na: 0.01 mmol center dot L-1 H2O2 + 70 mmol center dot 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 center dot L-1 H2O2 concentration was the better treatment concentration in this study.