Comparison of Stress Effect of NaCl, Na+ and Cl- on Two Chrysanthemum Species

In order to compare the stress effect of NaCl, Na+-salt and Cl--salt on the physiological responses in Chrysanthemum, the seedlings of Chrysanthemum okiense and C. ornatum were cultured in 0.75 fold diluted Hogland solution supplemented with NaCl, Na+(without Cl-) and Cl-(without Na+) with the osmotic potential of -0.64 Mp. Plants cultured in 0.75 fold diluted Hogland solution were used as control. The plant biomass, chlorophyll content, malondialdehyde (MDA) content, proline content and electrolyte leakage were investigated in the control plant and salt stressed plants. The plant biomass and chlorophyll content were decreased, while MDA content, proline content and electrolyte leakage were increased under either NaCl, Na+-salt or Cl--salt stress. The changes in five parameters were obviously affected by Cl--salt, moderately by NaCl, and lesser by Na+-salt in turn. C. ornatum was more affected by the three kinds of salt stress than C. okiense in terms of the five parameters. In sum, Cl- is the main cause for salt stress compared to Na+, and C. okiense is more salt tolerant than C. ornatum.