Effects of zinc chemistry on phytoextraction in Thlaspi caerulescens-vermiculite system
2005
Qian, X.D.(Kyushu Univ., Fukuoka (Japan)) | Eguchi, T. | Yoshida, S. | Chikushi, J.
Zinc phytoextraction capability of the hyperaccumulator is usually limited by zinc content in the soil. To investigate the effects of different zinc fractions (water-soluble, exchangeable, and non-exchangeable) on phytoextraction of Thlaspi caerulescens from medium of vermiculite, pot experiments were performed for various zinc application treatments (0-2000 mg kg(-1)). Relationships between zinc quantity accumulated in the plants and zinc content in the medium were investigated. Zinc content accumulated in the shoot of T. caerulescens increased and approached a constant value with zinc content in vermiculite. The analysis of zinc balance in vermiculite before and after the growth of T. caerulescens revealed that more than 40% of the zinc content accumulated by T. caerulescens is contributed by exchangeable zinc and that a high linear correlation exists between the zinc content in shoot of T. caerulescens and the initial exchangeable zinc in vermiculite. Moreover, 17.73-32.94% of the total zinc uptake by T. caerulescens was from non-exchangeable fraction. Thus, it was suggested that exchangeable zinc predominantly influenced the zinc uptake by plants and that T. caerulescens could contribute to the mobilization of non-labile zinc fraction in vermiculite.
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