###### Abstract  
Three different types of common halophytes (_Haloxylon ammodendron_, _Tamarix chinensis_, and _Pirmagnites australis_) in northwest China were used in this study. A field experiment approach was adopted, involving five solutions with different salt concentrations (0, 150, 200, 250, and 300 mmol\(\cdot\)L\({}^{-1}\)) for salt stress treatment. The changes in photosynthetic characteristics and physiological characteristics of three different types of halophytes and their relationship with biomass were measured and analyzed. The results showed that (1) with the increase in salt concentration, the plant height, stem diameter, and biomass of three halophytes showed a downward trend. (2) The chlorophyll a, chlorophyll b, and total chlorophyll contents of _Haloxylon ammodendron_ and _Tamarix chinensis_ first increased and then decreased with the increase in salt concentration. _Pirmagnites australis_ showed a decreasing trend. The malondialdehydedehyde content of three halophytes showed a clear increasing trend. (3) Under different salt concentrations, the diurnal changes in the net photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency of three different types of halophytes all showed an \"M\" trend. The diurnal variation in intercellular carbon dioxide concentration showed a \"W\" trend. (4) With the increase in salt concentration, the daily average values of the net photosynthetic rate, transpiration rate, and stomatal conductance of three different types of halophytes showed a downward trend. The daily average value of intercellular carbon dioxide concentration showed a \"V\"-shaped trend of first decreasing and then increasing. The daily average value of water use efficiency showed a \"single peak\" trend of first increasing and then decreasing. _Haloxylon ammodendron_ and _Pirmagnites australis_ were mainly limited by stomata at a salt concentration of 0-200 mmol\(\cdot\)L\({}^{-1}\) and were mainly limited by non-s stomata at a salt concentration of 250-300 mmol\(\cdot\)L\({}^{-1}\). _Tamarix chinensis_ is mainly limited by stomata at a salt concentration of 0-250 mmol\(\cdot\)L\({}^{-1}\) and is mainly limited by non-s stomata at a salt concentration of 300 mmol\(\cdot\)L\({}^{-1}\). Compared with _Haloxylon ammodendron_ and _Pirmagnites australis_, _Tamarix chinensis_ has better water use efficiency, salt tolerance, and adaptability. (5) Meteorological factors, growth morphological factors, physiological factors, photosynthetic factors, and salt concentration have higher explanatory degrees, which have significant effects on the biomass of halophytes. Among them, salt concentration and growth morphological factors have direct core driving effects on the biomass of three different types of halophytes, while meteorological factors, photosynthetic factors, and physiological factors have different effects due to the differences in and complexity of halophytes. This study can provide a theoretical basis for further revealing the adaptation mechanism of different halophytes to salt stress.  
salt stress; halophytes; ecological factors; biomass; ecological recovery Article Photosynthetic and Physiological Characteristics of Three Common Halophytes and Their Relationship with Biomass Under Salt Stress Conditions in Northwest China  
[PERSON]  
1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; [EMAIL_ADDRESS] (X.Z.) [EMAIL_ADDRESS] (G.G.); [EMAIL_ADDRESS] (H.D.)  
2 Engineering Technology Innovation Centre for Desert-Oasis Ecological Monitoring and Restoration, Ministry of Natural Resources, Urumqi 830011, China; [EMAIL_ADDRESS] 2  
3 College of Geographic Science and Tourism, Xinjiang Normal University, Urumqi 830054, China  
4 Xinjiang Uygur Autonomous Region Comprehensive Land Management Centre, Urumqi 830011, China  
* Correspondence: [EMAIL_ADDRESS]