RESUMEN
In this study, the effects of Ca(H2PO4)2, KH2PO4 and (NH4)2HPO4 on growth, Cu phytoextraction and tolerance of Leersia hexandra swartz (L. hexandra) under different Cu stress levels were investigated. The results showed that KH2PO4 could most significantly increase the plant height of L. hexandra (p < 0.05), while (NH4)2HPO4 had the most significant promoting effect on its biomass (p < 0.05) by enhancing photosynthesis (chlorophyll content) (p < 0.01). The application of Ca(H2PO4)2 could most significantly improve the Cu contents in roots, stems and leaves of L. hexandra (p < 0.05). In addition, (NH4)2HPO4 could enhance the tolerance of L. hexandra to Cu by obviously reducing the content of MDA and increasing the contents of SP and MTs (p < 0.05), while Ca(H2PO4)2 could evidently improve the activity of antioxidant enzymes (SOD, POD, CAT and APX) to reduce the damage of Cu to L. hexandra (p < 0.05). Although KH2PO4 could increase the contents of SP and MTs, the L. hexandra in KH2PO4 treatment groups had the highest MDA contents, which was unfavorable to the resistance to Cu stress. These suggested that the application in combination of Ca(H2PO4)2 and (NH4)2HPO4 may be more advantageous for Cu phytoextraction by L. hexandra.