Effects of phosphorous fertilizers on growth, Cu phytoextraction and tolerance of Leersia hexandra swartz under different Cu stress levels

Abstract

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.

Keywords:

• Cu phytoextraction
• Leersia hexandra swartz
• phosphorus fertilizer
• physiological characteristics
• phytoremediation

Additional information

Funding

This work was supported by the National Natural Science Foundations of China [NO. 51608143, NO. 51638006], China-Cambodia Laboratory of Water Environment Protection Co-constructed by Guilin University of Technology, China and Institute of Technology of Cambodia [GuikeAD17195023], Guangxi Graduate Education Innovation Project, Guangxi Scientific Experiment Center of Mining, Metallurgy and Environment [KH2012ZD004], the Guangxi Talent Highland for Hazardous Waste Disposal Industrialization, the project of high level innovation team and outstanding scholar in Guangxi colleges and universities [002401013001], and Special Funding for Guangxi ‘BaGui Scholar’ (Huijuan Liu) Construction Projects.