Selective uptake, distribution, and redistribution of 109Cd, 57Co, 65Zn, 63Ni, and 134Cs via xylem and phloem in the heavy metal hyperaccumulator Solanum nigrum L
2014
Wei, Shuhe | Anders, Iwona | Feller, Urs
The focus of this article was to explore the translocation of¹⁰⁹Cd,⁵⁷Co,⁶⁵Zn,⁶³Ni, and¹³⁴Cs via xylem and phloem in the newly found hyperaccumulator Solanum nigrum L. Two experiments with the uptake via the roots and transport of¹⁰⁹Cd,⁵⁷Co, and⁶⁵Zn labeled by roots, and the redistribution of¹⁰⁹Cd,⁶⁵Zn,⁵⁷Co,⁶³Ni, and¹³⁴Cs using flap label in S. nigrum in a hydroponic culture with a standard nutrient solution were conducted. The results showed that¹⁰⁹Cd added for 24 h to the nutrient medium of young plants was rapidly taken up, transferred to the shoot, and accumulated in the cotyledons and the oldest leaves but was not efficiently redistributed within the shoot afterward leading to a rather low content in the fruits. In contrast,⁵⁷Co was more slowly taken up and released to the shoot, but afterward, this element was redistributed from older leaves to younger leaves and maturing fruits.⁶⁵Zn was rapidly taken up and transferred to the shoot (mainly to the youngest leaves and not to the cotyledons). Afterward, this radionuclide was redistributed within the shoot to the youngest organs and finally accumulated in the maturing fruits. After flap labeling, all five heavy metals tested (¹⁰⁹Cd,⁵⁷Co,⁶⁵Zn,⁶³Ni,¹³⁴Cs) were exported from the labeled leaf and redistributed within the plant. The accumulation in the fruits was most pronounced for⁶³Ni and⁶⁵Zn, while a relatively high percentage of⁵⁷Co was finally found in the roots.¹³⁴Cs was roughly in the middle of them. The transport of¹⁰⁹Cd differed from that previously reported for wheat or lupin and might be important for the potential of S. nigrum to hyperaccumulate cadmium.
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