Effect of Salt-mist Stress on Physiological Properties of Seven Native Tree Species in Zhoushan

Experiments were implemented in November of 2012 on the container seedlings of Cinnamomum japonicum var. chenii, Neolitsea sericea, Machilus thunbergii, Ilex integra, Lithocarpus glaber, Raphiolepis umbellate and Eurya emarginata sprayed by 18‰ salt-mist with 0, 0.5, 1 and 2 hours a day for 35 days. Determinations were conducted on free proline and chlorophyll content and relative electrical conductivity of treated seedling leaves. The result showed that along with duration of stress, proline content of M. thunbergii, C. japonicum var. chenii, E. emarginata, N. sericea and L. glaber increased first, and then decreased, while that of I. integra, R. umbellata changed little. Chlorophyll content of treated seedlings topped at the middle stage of the treatment. By the end of the experiment, chlorophyll content of R. umbellata increased significantly, that of N. sericea changed little, that of L. glaber and M. thunbergii decreased, that of the left species had no evident regular changes. Relative electricity conductivity of I. integra and R. umbellata had little increase, and that of left tree species had great increase, and topped in the last day of treatment.