Low Molecular Weight Organic Acids Increase Cd Accumulation in Sunflowers through Increasing Cd Bioavailability and Reducing Cd Toxicity to Plants

The use of low molecular weight organic acids (LMWOAs) for the phytoremediation heavy metals has become a promising technique. We chose five kinds (oxalic acid (OA), acetic (AA), tartaric (TA), malic (MA), and citric (CA)) with six application rates (1, 2, 3, 4, 5, 6 mmol/kg) planted sunflowers (Helianthus annuus L.) in Cd-polluted soil to study efficiency Cd degree toxicity plants. Treatment no served as control (CK). analyzed plant height dry matter nonprotein sulfhydryl (NPT) contents tissues. OA, AA, TA, MA, CA increased heights by 17.6–47.40%, 21.25–39.17%, 12.5–35.52, 5.10–30.50%, 16.15–49.17%, respectively; shoot biomass was except MA. NPT decreased under LMWOA application, which, roots, increase root treatment; however, there obvious relationship stems leaves. composition changed significantly treatments compared CK, changes carbonate Fe-Mn oxide were most prominent. accumulation 43.31%, 55.25%, 48.69%, 0.52%, 32.94%, respectively, content quality promoted accumulation. LMWOAs more likely affect changing total P (TP) rather than N (TN).