Fruit extracts from Phyllanthus emblica accentuate cadmium tolerance and accumulation in Platycladus orientalis: A new natural chelate for phytoextraction.

A key challenge for phytoextraction is the identification of high efficiency, growth-supporting, and low cost chelating agents. To date, no substance has satisfied all above criteria. This study investigated nine traditional Chinese herbs and found that Phyllanthus emblica fruit (FPE) extract could be utilised as an optimal chelate for the phytoextraction of cadmium (Cd)-contaminated soils. FPE application into soil at a ratio of 0.1% (w/w) significantly increased extractable Cd (by 43%) compared to the control. The success of FPE as a chelating agent was attributed to high quantities of polyphenol compounds (0.76%) and organic acids (9.6%), in particular, gallic acid (7.6%). Furthermore, antioxidative properties (1.4%) and free amino acids in FPE alleviated Cd-induced oxidant toxicity and enhanced plant biomass. FPE promoted 78% higher phytoextraction efficiency in Platycladus orientalis compared to traditional chelating agents (EDTA). Furthermore, 76% of FPE was degraded 90 days after the initial application, and there was no difference in extractable Cd between the treatment and control. FPE has been commercially produced at a lower market price than other biodegradable chelates. As a commercially available and cost-effective chelator, FPE could be utilised to treat Cd-contaminated soils without adverse environmental impacts.

Identification of high cadmium-accumulating oilseed sunflower (Helianthus annuus) cultivars for phytoremediation of an Oxisol and an Inceptisol.

Forty oilseed sunflower cultivars were screened in two soil types for phytoremediation of Cd coupled with maximum biomass yield and oil production. Several cultivars exhibited a significant difference in biomass and yield with enhanced uptake in shoots and low accumulation in roots from two Cd-contaminated soil types, an Oxisol and an Iceptisol. The Transfer Factor of Cd was >1 in several cultivars in both soil types, where as a significant difference in phytoextraction of Cd was observed in the Oxisol (acidic soil), greater than in the Inceptisol (alkaline soil). The results revealed that of the 40 cultivars, S9178, Huanong 667in the Oxisol and cvs. DW 667, HN 667, Huanong 667 and 668F1 in the Inceptisol showed a high biomass, better yield and enhanced accumulation of Cd in the shoots but a lesser accumulation in oil. The screened cultivar S 9178 produced the greatest amount of oil (55.6%) with 77% oleic acid, which makes it suitable for human consumption. Cultivar Huanong 667 was found to be the highest accumulating cultivar in both soil types. It is therefore suggested that some sunflower cultivars do exhibit phytoremediation potential together with agro-production potential.