Effects of NaCl Stress on Photosynthetic Characteristic of Garden Seedlings of 4 Species

The effects of NaCl stress on photosynthesis of seedlings of 4 species were studied to provide a reference for garden plant selection of salt tolerant. Seedlings of Hibiscus rosa-sinensis, Ixora chinensis, Schefflera arboricola, Cordyline fruticosa were placed in simulating salt environment, and then their photosynthetic indexes were determined. Results showed that at 0.3% salt concentration, with increasing salt stress time, P_n of the 4 species continuously decreased. G_s of H. rosa-sinensis continuously decreased, whereas the other species decreased followed by an increase. C_i of H. rosa-sinensis and S. arboricola continuously decreased, and I. chinensis decreased followed by an increase, C. fruticosa continuously increased. T_r of H. rosa-sinensi continuously decreased, and the other species decreased followed by an increase. At 0.6% salt concentration, P_n of seedlings of the 4 species continuously decreased. G_s of H. rosa-sinensis, I. chinensis and S. arboricola decreased followed by an increase, C. fruticosa continuously decreased. C_i of H. rosa-sinensis, I. chinensis and S. arboricola decreased followed by an increase, whereas C. fruticosa increased and then decreased. T_r of seedlings of the 4 species decreased followed by an increase. The overall judgment from P_n, G_s, C_i and T_r of the 4 plant species, H. rosa-sinensis and S. arboricola had stronger salt tolerance among 4 species and was more suitable for cultivation in salt land, and salt tolerance of I. chinensis was medium, whereas that of C. fruticosa was weaker.