Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii:the impact of citric acid and tartaric acid

The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils.Organic acid has been suggested to be involved in toxic metallic element tolerance,translocation,and accumulation in plants.The impact of exogenous organic acids on cadmium(Cd) uptake and translocation in the zinc(Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study.By the addition of organic acids,short-term(2 h) root uptake of 109 Cd increased significantly,and higher 109 Cd contents in roots and shoots were noted 24 h after uptake,when compared to controls.About 85% of the 109 Cd taken up was distributed to the shoots in plants with citric acid(CA) treatments,as compared with 75% within controls.No such effect was observed for tartaric acid(TA).Reduced growth under Cd stress was significantly alleviated by low CA.Long-term application of the two organic acids both resulted in elevated Cd in plants,but the effects varied with exposure time and levels.The results imply that CA may be involved in the processes of Cd uptake,translocation and tolerance in S.alfredii,whereas the impact of TA is mainly on the root uptake of Cd.

Caffeic acid product from the highly copper-tolerant plant Elsholtzia splendens post-phytoremediation:its extraction,purification,and identification

In the current study,caffeic acid was an important metabolite in the highly copper-tolerant plant Elsholtzia splendens.Preparation and purification of caffeic acid were performed on the dried biomass of the plants by means of sonication/ethanol extraction,followed by purification using a macroporous resin (D101 type) column and silica gel chromatography.The faint-yellow caffeic acid product was yielded with a purity of 98.46%,and it was chemically identified from spectra of Fourier transform infrared spectroscopy (FTIR),proton nuclear magnetic resonance (1 H NMR)/carbon nuclear magnetic resonance (13 C NMR),and electrospray ionization mass spectrometry (ESI-MS).Caffeic acid is a possible product from the post-harvest processing of Elsholtzia splendens biomass.

Extraction and isolation of the salidroside-type metabolite from zinc(Zn) and cadmium(Cd) hyperaccumulator Sedum alfredii Hance

The active metabolite in the post-harvested biomass of zinc(Zn) and cadmium(Cd) hyperaccumulator Sedum alfredii Hance from phytoextraction is of great interest in China.The current study demonstrates that a salidroside-type metabolite can be yielded from the Zn/Cd hyperaccumulator S.alfredii biomass by means of sonication/ethanol extraction and macroporous resin column(AB-8 type) isolation.The concentrations of Zn and Cd in the salidroside-type metabolite were below the limitation of the national standards.

Apigenin-7-O-β-D-glycoside isolation from the highly copper-tolerant plant Elsholtzia splendens

Elsholtzia splendens （Lamiaceae） is a copper-tolerant plant species growing on copper deposits in the south of China. Chromatographic separation of n-BuOH extracts from the flowering aerial biomass afforded apigenin- 7-O-β-D-glycoside, using macroporous resin, SephadexTM LH-20 gel, polyamide resin as well as preparative high- performance liquid chromatography （P-HPLC） columns. Chemical structure was elucidated using HPLC/ESI-MS （electrospray ionization-mass spectrometry）, Fourier transform infrared （FTIR）, and 1D- and 2D-nuclear magnetic resonance （NMR）. Apigenin-7-O-β-D-glycoside could be the post-harvesting product from E. splendens biomass.