Research Of Salt-resistance Physiology Of Seven Species Of Landscape Seedlings

In this study, seedlings of Hibiscus rosa-sinensis, Ervatamia divaricata, Ixora chinensis, Excoecaria cochinchinensis, Schefflera arboricola, Cordyline fruticosa, Duranta repens were placed in simulating salt environment, to determine their physiological, photosynthetic and fluorescent indexes, and principal component method was used to evaluate salt resistance of these plants, the results were as follows:1. At 0.3 % salt concentration, with increasing salt stress time, the chlorophyll content soluble sugar content, SOD activity and membrane permeability of the seven species of seedlings tended to increase; proline content of H. rosa-sinensis increased and then decreased, E. divaricata and S. arboricola continued to increased, I. chinensis and D. repens decreased followed by an increase, whereas E. cochinchinensis and C. fruticosa continuously decreased; protein content of H. rosa-sinensis, S. arboricola, E. cochinchinensis, I. chinensis seedlings continuously increased, E. cochinchinensis, C. fruticosa with D. repens increased followed by a decrease; MDA content of H. rosa-sinensis, S. arboricola and C. fruticosa continuously increased, I. chinensis and D. repens increased and then decreased, whereas E. divaricata and E. cochinchinensis decreased followed by an increase.At 0.6 % salt concentration, chlorophyll content and proline content of the six species of seedlings except for E. cochinchinensis increased and then decreased; soluble sugar content and the relative membrane permeability of the seven species of seedlings tended to increase, soluble protein content of the six species of seedlings except for I. chinensis increased and then decreased; SOD activity of the seven species of seedlings increased and then decreased; MDA content of H. rosa-sinensis, E. divaricata, I. chinensis, S. arboricola continuously increased, E. cochinchinensis, D. repens decreased followed by an increase,C. fruticosa increased and then decreased.2. At 0.3 % salt concentration, with increasing salt stress time, Pn of the seven species of seedlings continuously decreased; Gs of H. rosa-sinensis, E. divaricata and D. repens continuously decreased, I. chinensis, S. arboricola and C. fruticosa decreased followed by an increase, whereas E. cochinchinensis increased and then decreased; Ci of Hibiscus rosa-sinensis, E. divaricata, S. arboricola and D. repens, I. chinensis decreased followed by an increase, E. cochinchinensis increased and then decreased, C. fruticosa continuously increased; Tr of H. rosa-sinensis, E. divaricata and E. cochinchinensis continuously decreased, I. chinensis, S. arboricola, C. fruticosa and D. repens decreased followed by an increase.At 0.6 % salt concentration, Pn of H. rosa-sinensis, E. divaricata, I. chinensis and S. arboricola decreased followed by an increase, E. cochinchinensis, C. fruticosa and D. repens continuously decreased; Gs of H. rosa-sinensis, E. divaricata, I. chinensis and S. arboricola, decreased followed by an increase, other three species continuously decreased; Ci of H. rosa-sinensis, E. divaricata, I. chinensis, S. arboricola and D. repens decreased followed by an increase, E. cochinchinensis, C. fruticosa increased and then decreased; Tr of the seven species of seedlings decreased followed by an increase.3. At 0.3 % salt concentration, with increasing salt stress time, Fv/Fm of H. rosa-sinensis, E. divaricata, I. chinensis, S. arboricola and D. repens continuously decreased, while the E. cochinchinensis and C. fruticosa decreased followed by an increase; Fo of S. arboricola seedlings continuously increased, the other species of seedlings increased and then decreased; Fm of seven species of seedlings increased and then decreased; Y(II) of S. arboricola increased and then decreased, other species of seedlings continuously decreased; ETR of S. arboricola increased and then decreased, other species of seedlings continuously decreased; NPQ of D. repens continuously decreased, whereas other species of seedlings decreased followed by an increase.At 0.6 % salt concentration, Fv/Fm of seven species of seedlings continuously decreased; Fo and Fm of C. fruticosa seedlings continuously increased, the other species of seedlings increased and then decreased; Y(II) of S. arboricola seedlings decreased followed by an increase, C. fruticosa increased and then decreased, and the other species continuously decreased; ETR of S. arboricola decreased followed by an increase, C. fruticosa increased and then decreased, the other species of seedlings continuously decreased; NPQ of H. rosa-sinensis continuously increased, S. arboricola continuously decreased, other species of seedlings decreased followed by an increase.Principal component analysis was to evaluate physiological, photosynthetic and chlorophyll fluorescence indexes, and the results showed that at 0.3 % salt concentration, physiological index score of seven species of seedlings decreased in the order of E. cochinchinensis>D. repens>C. fruticosa>E. divaricata > H. rosa-sinensis > S. arboricola > I. chinensis, their photosynthetic index score decreased in the order of C. Fruticosa > I. Chinensis > S. Arboricola > E. cochinchinensis > E. divaricata > D. repens > H. rosa-sinensis, their fluorescence index score decreased in the order of C. fruticosa > E. divaricata > E. cochinchinensis > I. chinensis>D. repens > H. rosa-sinensis > S. arboricola.At 0.6 % salt concentration, physiological index score of seven species of seedlings decreased in the order of E. cochinchinensis> D. repens > C. fruticosa > E. divaricata > H. rosa-sinensis > S. arboricola > I. chinensis; their photosynthetic index score decreased in the order of E. cochinchinensis > E. divaricata > I. chinensis > C. fruticosa > H. rosa-sinensis > D. repens > S. arboricola; their fluorescence index score decreased in the order of C. fruticosa > S. arboricola > I. chinensis > E. divaricata > E. cochinchinensis > D. Repens > H. rosa-sinensis.