Effect of Salt Spray Stress on Photosynthetic Physiology of Viburnum japonicum with Extremely Small Population

Abstract:

Viburnum japonicum is a species with extremely small populations, only distributing on islands. In order to evaluate the effect of salt spray stress on growth of V. japonicum, 4-year-old seedlings were treated with different salt spray concentrations (mass concentrations of NaCl in salt spray were 0%, 1%, 2% and 3%, respectively), the changes in photosynthetic rate, maximum photochemical efficiency (F_v/F_m), chlorophyll content (Chl) were measured. The results showed that V. japonicum treated with 1% salt spray could survive, but all plants died treated with more than 2% salt spray. With the increment of salt spray concentration, the maximum photosynthetic rate, F_v/F_m and Chl content in leaves generally decreased, and the light saturation point and light compensation point showed an upward trend. Therefore, it was indicated that salt spray stress affected plant photosynthesis by harming photosystem II reaction center, changing the range of available light energy and reducing chlorophyll content.

Key words:Viburnum japonicum;Salt spray stress;Salt tolerance;Photosynthetic characteristics