title: Effects of PEG-Induced Water Deficit in Solanum nigrum on Zn and Ni Uptake and Translocation in Split Root Systems.
abstract: Drought strongly influences root activities in crop plants and weeds. This paper is focused on the performance of the heavy metal accumulator Solanum nigrum, a plant which might be helpful for phytoremediation. The water potential in a split root system was decreased by the addition of polyethylene glycol (PEG 6000). Rubidium, strontium and radionuclides of heavy metals were used as markers to investigate the uptake into roots, the release to the shoot via the xylem, and finally the basipetal transport via the phloem to unlabeled roots. The uptake into the roots (total contents in the plant) was for most makers more severely decreased than the transport to the shoot or the export from the shoot to the unlabeled roots via the phloem. Regardless of the water potential in the labeling solution, (63)Ni and (65)Zn were selectively redistributed within the plant. From autoradiographs, it became evident that (65)Zn accumulated in root tips, in the apical shoot meristem and in axillary buds, while (63)Ni accumulated in young expanded leaves and roots but not in the meristems. Since both radionuclides are mobile in the phloem and are, therefore, well redistributed within the plant, the unequal transfer to shoot and root apical meristems is most likely caused by differences in the cell-to-cell transport in differentiation zones without functional phloem (immature sieve tubes).
authors.affiliation: Institute of Plant Sciences and Oeschger Centre for Climate Change Research, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland. urs.feller@ips.unibe.ch.
authors.forename: Urs
authors.initials: U
authors.lastname: Feller
authors.affiliation: Institute of Plant Sciences and Oeschger Centre for Climate Change Research, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland. iwona.anders@ips.unibe.ch.
authors.forename: Iwona
authors.initials: I
authors.lastname: Anders
authors.affiliation: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China. shuhewei@iae.ac.cn.
authors.forename: Shuhe
authors.initials: S
authors.lastname: Wei
keywords: Solanum nigrum L.; cations; drought; heavy metals; phloem; radionuclides; split root system; transport; xylem