The Addition of KNO3 and (NH4)3PO4 Maybe Improves the Ability to Accumulate Cd by Regulating the Redistribution of Nutrients in Bermudagrass

Abstract The application of fertilizer can improve the Cd enrichment efficiency of plants, but the changes of nitrogen (N), phosphorus (P), potassium (K) in the growth medium have different impacts on Cd enrichment efficiency of plants. In this study, hydroponic experiment by adding different KNO3 and (NH4)3PO4 was carried out to study whether and how the addition of available N, P and K can improve Cd accumulation. The four treatments were CK, 0.4 mg kg-1 Cd (Cd), 0.4 mg kg-1 Cd and KNO3 (COK), 0.4 mg kg-1 Cd and (NH4)3PO4 (CNP). The results showed that the chlorophyll contents, PSII maximum photochemical quantum efficiency (Fv/Fm) and PSII potential activity (Fv/Fo) of COK and CNP were higher than that of CD. There was no significant difference between CK and CNP (P > 0.05). The N, P and K contents and Cd concentrations of roots and stems of COK and CNP were significantly higher than those of CD(P＜0.05).The BCF of COK and CNP were also significantly higher than that of CD, increasing by 39.8% and 37.6%, respectively. The root, stem and leaf dry weight of COK and the root and stem dry weight of CNP were higher than that of CD, and the biomass of the whole basin was significantly higher than that of CD (P＜0.05), but with no significant difference from that of CK (P＞0.05). In addition to stem K accumulation of CNP, N, P and K allocated to root and stem in COK and CNP were significantly higher than that in CD (P＜0.05). There was no significant difference in pH and water soluble Cd content among CD, COK and CNP (P＞0.05). it was concluded that plants can improve their Cd accumulation ability by changing biomass and nutrient allocation. The conclusion provides a theoretical basis for improving soil environmental factors by improving fertilization strategies of related plants so as to improve Cd enrichment ability.