Studies On The Effects Of NaCl Stress On The Physiological And Biochemical And Photosynthesis Characteristics Of 4 Seedlings

This paper had dealt with the study on the one-year seedlings of Neolitsea sericea and Cinnamomum japonicum.and Hibiscus hama and Casuarinn equiestifolia with the pot planting experiments in greenhouse,especially putting emphasis on the study of the Neolitsea sericea and Cinnamomum japonicum.Based on the investigation and research of the seedling physiological properties and the effects of photosynthetic active radiation under the four NaCl treatments (density respectively content of 3g/L, 5g/Land 7g/L) were studied comprehensively on the basis of data analyses by mathematical methods such as correlation analysis,compare analysis and subordination function method etc.The aim was to provide theorial basis for developing local plantations in inshore beach.The main conclusions were drawn as follows by the analyses of many indexes :1.The high growth of Cinnamomum japonicum was promoted,but was inhibited to Neolitsea sericea,Hibiscus hamabo and Casuarinn equiestifolia actually.Totally,the effects of high growths about 4 tree seedling were arranged in NaCl treatments Cinnamomum japonicum < Neolitsea sericea < Casuarinn equiestifolia < Hibiscus hamabo.2. The content of chlorophyll of four trees were all raised in 3g/L NaCl treatment,but the range of their changes were littler than early days.The effects of chlorophyll of Cinnamomum japonicum and Neolitsea sericea reached significant level or respectively under different salt stress.3. The content of MDA of four trees presented degressive trend as a whole along with the time increase and showed the capability of strong durable NaCl.The effects of MDA of Cinnamomum japonicum and Neolitsea sericea reached significant level respectively under different salt stress.4. The content of Proline of Neolitsea sericea,Casuarinn equiestifolia,Hibiscus hamabo increased at first and decreased subsequently as a whole along with the time increase, and were consistent with the comparison. The content of Proline of Cinnamomum japonicum reached significant level respectively with the comparison(P<0.01).The tolerance to salt of the four trees species was in order of Neolitsea sericeaï¹¥Hibiscus hamaboï¹¥Cinnamomum japonicumï¹¥Casuarinn equiestifolia.5. The activity of SOD of four trees increased at first and decreased subsequently as a whole along with the time and density respectively content increase.The SOD activity of Neolitsea sericea,Cinnamomum japonicum were higher than the comparison at last,but they did not reach significant level under different salt stress.The SOD activity of Casuarinn equiestifolia was lower than the comparison and first stress respectively.6. The activity of POD of Neolitsea sericea and Cinnamomum japonicum increased at first and decreased subsequently as a whole along with the time and density respectively content increase, and Hibiscus hamabo and Casuarinn equiestifolia were just increase.The activity of POD of Neolitsea sericea, Cinnamomum japonicum and Casuarinn equiestifolia were higher than the comparison at last,reached significant level.The effect of POD activity was significant to four trees under the stress of 5 g/L and 7g/L salt density. 7. Under salt stress,various physiological and biochemical indexes of Neolitsea sericea and Cinnamomum japonicum were independent. The result inferred from analysis of significance difference with the comparison is that the content of MDA,Chls,POD activity and MDA, Pro, POD activity could be the main indexes to reflect respectively the tolerance ability of against salt.8. The net photosynthesis rate of Neolitsea sericea was higher than Cinnamomum japonicum in the same salt density.The net photosynthesis rate of Neolitsea sericea and Cinnamomum japonicum presented higher in the low salt density stress among the salt stress.The biggest net photosynthesis rate of Neolitsea sericea decreased, but Cinnamomum japonicum increased.9. The light compensation point of Neolitsea sericea and Cinnamomum japonicum were different obviously between different salt density stress and variety trees, but the light saturation point was reverse. The light saturation point and the apparent photosynthetic quantum yields (AQY) were decreased obviously along with the salt density increase.10. Fv/Fm and Fv/Fo presented that Neolitsea sericea was higher than Cinnamomum japonicum.The relativity of Fv /Fm and Fv/Fo increased along with the salt density increase. Salt stress was not effect to Fv/Fm and Fv/Fo.11. Comprehensive evaluation of the resistance of four ornamental tree species to salt was made by using the subordination function method of vague mathematics to analyze six indexes.The salt resistance of the eleven tree species from strong to weak is as the followings:Cinnamomum japonicumï¹¥Hibiscus hamaboï¹¥Neolitsea sericeaï¹¥Casuarinn equiestifolia.