Salt Tolerance Characteristics And Soil Soluble Salt Ion Uptake Of Three Dominant Plant Species In The Qaidam Basin

Soil salinisation is a major ecological constraint,and soluble salt ions are an important indicator of the degree of soil salinisation.Soil salinisation in Gahai Lake and Koruk Lake Nature Reserve has severely restricted the development of the local ecological environment.In this paper,three dominant plant species,Kalidiumfoliatum（Pall.）Moq.,Nitrariatangutorum Bobrov and Phragmitesaustralis（Cav.）Trin.ex Steud.,were used as research objects to investigate the content of soluble salt ions,osmoregulatory substances and antioxidant enzyme activities in the above-ground stems and leaves and underground roots of the plants,respectively,and the content of soluble salt ions in different soil profiles.The aim was to characterise the content of soluble salt ions in soil and plants and the response of dominant species to higher levels of soluble salt ions in soil.The results show:（1）The soluble salt ions in the three dominant species were distinctive,with Ca²⁺being the highest,HCO^3-and CO₃^2-the lowest,and Na⁺the lowest in both above-and below-ground parts of the plant.The Mg²⁺、SO₄^2-、Cl^-、K⁺soluble salt ions in the above-ground stems and leaves of Nitrariatangutorum Bobrov,Kalidiumfoliatum（Pall.）Moq.and Phragmitesaustralis（Cav.）Trin.ex Steud.,and in the below-ground root fractions,were all unique.（2）The soluble salt ions in the soils where the three dominant species are grown are distinctive,with different characteristics of ion content and species at different depths in the profile,and the individual ion content in the soils where the different plants are grown show a variety of trends from 20cm to 100cm of the soil profile,such as an increase followed by a decrease,a small increase followed by a decrease and then an increase.（3）The three dominant species differed in their selective uptake of In the Gahai Lake and Koruk Lake Nature Reserves,Nitrariatangutorum Bobrov is mostly found in areas with high salinity,high Cl^-content in the soil and Ca²⁺-Cl^-soil type;Kalidiumfoliatum（Pall.）Moq.is mostly found in areas with low salinity,high SO42 content in the soil and Ca²⁺-SO₄^2-soil type;Phragmitesaustralis（Cav.）Trin.ex Steud.is found in areas with medium salinity,high Mg²⁺content in the soil and Ca²⁺-Mg²⁺-Cl^-soil type.Reeds are distributed in areas with medium salinity,high soil Mg²⁺content and Ca²⁺+-Mg²⁺-Cl^-soil type.（4）soil soluble salt ions.The selective uptake coefficients were S_SO42-,Ca2+>S_Cl-,Ca2+>S_Mg2+,Ca2+for Nitrariatangutorum Bobrov,S_SO42-,Ca2+>S_Mg2+,Ca2+for Kalidiumfoliatum（Pall.）Moq.,and S_Cl-,Ca2+>S_SO42-,Ca2+>S_Mg2+,Ca2+for Phragmitesaustralis（Cav.）Trin.ex Steud.The uptake of Mg²⁺by the three dominant species was Phragmitesaustrali-s（Cav.）Trin.ex Steud>Kalidiumfoliatum（Pall.）Moq.>Nitrariatangutor-um Bobrov;the uptake of SO₄^2-was Nitrariatangutorum Bobrov>Phr-agmitesaustralis（Cav.）Trin.ex Steud and Kalidiumfoliatum（Pall.）Moq.;the uptake of Cl^-was Phragmitesaustralis（Cav.）Trin.ex Steud>Nitraria-tangutorum Bobrov.（5）Nitrariatangutorum Bobrov adapts to high salt content by increasing superoxide dismutase（SOD）and peroxidase（POD）activity in the underground root system and increasing proline synthesis and POD activity in the above-ground stems and leaves.Kalidiumfoliatum（Pall.）-Moq.adapted to progressively higher salt levels by increasing SOD in the underground root system and increasing proline synthesis in the aboveground stems and leaves.Phragmitesaustralis（Cav.）Trin.ex Steud adapt to progressively higher salt levels by increasing POD activity in the underground root system and increasing betaine synthesis and POD activity in the aboveground stems and leaves.