| Salt stress is a major abiotic stress which can greatly affect the growth of plant.The growth pattern,biomass,nutrients a nd soil fertility of Hibiscus rosa-sinensis,Ervatamia divaricat?Gouyahua‘,Ixora chinensis,Excoecaria cochinchinensis,Schefflera arboricola,Cordyline fruticosa and Duranta erecta?Variegata‘seedlings were studied in simulating salt environment,to evaluate salt tolerance of these plants and to find plant species with high salt-tolerance.The main results were as follows:?1?With the increase of salt concentration,the total biomass,aboveground biomass and underground biomass of the landscape plants of seven species decreased significantly.The decrease range of aboveground biomass of H.rosa-sinensis,E.divaricata and I.chinensis were greater than their underground biomass,but which was contrary to E.cochinchinensis,S.arboricola and D.repens.In the all salt concentration,the root-shoot ratio in the landscape plants of seven species was less than one.The root-shoot ratio of H.rosa-sinensis,E.divaricata,I.chinensis,and C.fruticosa increased with salt stress,whereas that of E.cochinchinensis,S.arboricola.,and D.repens?Variegata‘decreased.?2?Total water content of the landscape plants except for C.fruticosa increased with salt stress,and water content in leaves was greater than roots or stem.?3?Contents of Na,Cl,N,P,and K in different organs of the landscape plants ranged from 0.66 to 19.66,0.12 to 27.5,7.41 to 25.32,0.92 to 3.05 and 4.17 to 27.29 g·kg-1,respectively.The contents of N and K were higher than that of Na,C l and P,and the change ranges of Na and C l were larger than N,P,and K.Na content of different organs increased with increasing salt concentration.Na increment in leaves and stems was more than in roots.The C l content in different organs of the landscape plants except for S.arboricola and D.repens increased with increasing salt concentration.N content of organs of plants except for C.fruticosa and D.repens increased with salt stress.The P content of different organs of plants changed irregularly.With increasing salt concentration,K content increased in leaves of plants except for H.rosa-sinensis,and decreased in stem of plants except for H.rosa-sinensis,I.chinensis,and S.arboricola,decreased in roots except for E.divaricata.?4?N or K accumulations were greater than Na or C l and P accumulations.The change range of K and C l accumulations were great compared with N,P,and Na.With increasing salt concentration,Na accumulation increased in the landscape plants of seven species and their organs.Increase range of C l accumulations was large in leaves,branches and stem;C l accumulation of plants except for S.arboricola increased and roots had greatest C l accumulation among all organs.;N accumulation of organs of most plant species decreased gradually,whereas P and K accumulations decreased in the seven plant species;?5?Soil pH value under salt stress was different from plant species.Salt stress increased soil organic matters of plants except for E.divaricat and S.arboricola,and contents of total N,total P,available N and available P of most plant species.Soil available K content of plants except for E.divaricata and D.repens also increased under salt stress.Salt stress decreased soil catalase activity of plants except for H.rosa-sinensis and urease activity of plants except for S.arboricola and E.divaricata,but promoted soil phosphatase activity of E.divaricat?Gouyahua‘,I.chinensis,E.cochinchinensis and S.arboricola.?6?Salt tolerance of landscape plants of seven species was evaluated using the method of membership function by organ biomass and nutrient,indicating that salt-tolerance decreased in the order of E.divaricata>S.arboricola>D.erecta>C.fruticosa>H.rosa-sinensis>I.chinensis>E.cochinchinensis at 0.3%salt concentration,and in the order of E.divaricata>C.fruticosa>S.arboricola>H.rosa-sinensis>D.erecta>I.chinensis>E.cochinchinensi at 0.6%salt concentration. |
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