Effect Of Repair Agents On Growth And Element Absorption Of Suaeda Salsa In Cadmium Contaminated Saline Soil

At present,there is a large area of heavy metal contaminated saline soil in the world.Compound stress is more complex than heavy metal pollution or saline soil,which poses great challenges to soil remediation technology.The research on remediation of heavy metal contaminated saline soil by halophytes has gradually attracted the attention of scholars at home and abroad.However there are few studies on the remediation of heavy metal contaminated saline soil by halophytes strengthened by remediation agents.In this paper,through pot experiment in greenhouse.The plants tested were halophyte Suaeda salsa,simulated non salinization soil?Cd0S0?,Cd contaminated soil(3 mg·kg^-1,Cd3S0),NaCl saline soil(4 mg·kg^-1,Cd0S4)and Cd contaminated NaCl saline soil?Cd3S4?.Studying the effects of chelating agent EDTA(4 mmol·kg^-1)and biochar(15 g·kg^-1)on the growth of halophytes and the absorption and accumulation of cadmium and Na⁺in heavy metal contaminated saline soil.The results show that:?1?Cd0S4 treatment significantly increased biomass by 311.1%³41.7%.In Cd3S0,the root dry weight and total dry weight increased by 11.3 times and 3.3 times respectively when biochar was applied.?2?In Cd0S0,Cd0S4 and Cd3S0,biochar significantly increased P concentrations in shoots and roots by 155.0%⁴09.0%and 81.8%¹35.2%.Application of biochar significantly reduced N:P in shoots of Suaeda salsa in all treatments,the shoot C:P of Cd0S0 and Cd0S4 decreased significantly and the root C:N:P of Cd0S0 and Cd3S0 decreased significantly;biochar significantly increased K⁺/Na⁺and P/Na⁺in shoots and roots of Cd0S0,P/Na⁺in shoot and K⁺/Na⁺,P/Na⁺in root of Cd3S0,respectively.?3?Compared Cd0S4 with Cd3S4,applying remediation agents increased Na⁺concentration by 32.5%and 83.3%respectively;Compared Cd0S4 with Cd3S4 the concentration of Na⁺in roots increased by 39.6%and 94.5%without remediation agents and applying biochar;Compared with Cd0S4,Na⁺content in shoots and roots of Cd3S4 decreased significantly by 21.3%⁹0.9%;EDTA and biochar significantly reduced Na⁺content in roots of Cd0S4 by 29.6%and 29.4%,respectively.The Na⁺concentration and content in the shoots of Cd3S4 increased by 38.6%⁵6.0%and19.6%²89.3%respectively.?4?Cd3S4 compared with Cd3S0,Cd concentration in shoots of Suaeda salsa increased by 135.8%²23.6%and Cd content in shoots increased by 132.4%⁴71.5%.Compared with Cd3S0,Cd concentration in roots of Cd3S4 increased by 282.2%and Cd content in roots decreased by 56.8%.Biochar significantly reduced Cd concentration in Cd3S0 roots by 54.2%,increased Cd content in roots by 21 times,and increased Cd concentration in Cd3S4 roots by 31.1%.EDTA and biochar significantly increased Cd content in Cd3S4 shoots by 133.4%and 173.4%.?5?When biochar was applied,Cd3S4 was compared with Cd0S0 and Cd3S0,cell membrane permeability increased by 175.0%and 400.0%.The cell membrane permeability of Cd0S0 and Cd3S0 leaves decreased by 68.6%and 48.7%respectively by applying biochar.The results showed that in Cd-contaminated NaCl saline soil,the application of chelating agent EDTA and biochar could significantly promote the absorption and accumulation of Cd and Na⁺in the shoots of Suaeda salsa.It is hapieful to improve the phytoremediation efficiency of heavy metalcontaminated saline soil and it provides basic data and theoretical support for remediation of heavy metalcontaminated saline soil.