Zinc Hyperaccumulation and Uptake by Potentilla Griffithii Hook

Abstract

The ability of Potentilla griffithii Hook var. velutina Cardot to hypaeraccumulate zinc (Zn) was identified through field survey and hydroponic experiments. Our results showed that P. griffithii could be classified as a new Zn hyperaccumulator. Zn concentrations in the shoots of P. griffithii averaged 6250 mg kg⁻¹ (3870–8530 mg kg⁻¹) growing in Zn-rich soils. The highest Zn concentration was observed in the leaves of P. griffithii at 22,990 mg kg⁻¹. The fact that P. griffithii was able to grow in a mining soil with a Zn concentration of 193,000 mg kg⁻¹ without showing a major sign of phytotoxicity demonstrated its high tolerance to Zn. When growing in hydroponic systems, P. griffithii accumulated a maximum 26700 mg kg⁻¹ zinc concentration in the shoots, indicating the ability of this species to effectively take up and translocate Zn. Translocation factors (the ratio of Zn concentration in shoot to root) of 1.1 to 1.6 were obtained. Compared to the control, dry biomass of P. griffithii in 160 mg L⁻¹ Zn treatment increased 66.6% (P < 0.05). The time-course experiment showed that the maximum Zn concentration at 100 mg L⁻¹ Zn treatment was found at 16 d, much later than that of the 10 mg L⁻¹ Zn treatment, which might be an attribution of a accumulating mechanism or detoxification of a plant. The report of a new Zn hyperaccumulator provides a new plant species for the phytoremediation of contaminated soil and for the research on mechanisms of Zn hyperaccumulation in plants.

KEY WORDS:

• zinc (Zn)
• hyperaccumulator
• uptake
• P. griffithii
• phytoremediation

ACKNOWLEDGEMENTS

The authors are grateful to Prof.Ye Hua-gu of South China Botanical Garden, Chinese Academy of Sciences, and Tao De-ding, Senior Engineer, Kunming Institute of Botany, Academia Sinica, for identifying the plant. This project was supported by National Natural Science Foundation of China under grant 40571144, Guangdong Provincial Natural Science Foundation under grant 05101824, and New Century Excellent Talents Plan Program of National Education Ministry under grant NCET04-0790.