Choosing Tree Genotypes for Phytoremediation of Landfill Leachate Using Phyto-Recurrent Selection

Abstract

Information about the response of poplar (Populus spp.) genotypes to landfill leachate irrigation is needed, along with efficient methods for choosing genotypes based on leachate composition. Poplar clones were irrigated during three cycles of phyto-recurrent selection to test whether genotypes responded differently to leachate and water, and to test whether the methodology had merit as a tool for plant selection during remediation. Fifteen below-and above-ground traits were evaluated. Twenty-five clones were tested in cycle 1, while the best 12 genotypes were evaluated in cycles 2 and 3. Eight clones were selected and subsequently tested in an in situ landfill study (cycle 4). Results from cycles 1, 2, and 3 are presented here. Overall, clones responded differently to irrigation treatments, with certain genotypes exhibiting better below-and above-ground growth with water than leachate. However, growth was greater with leachate irrigation for some clones. In addition, differences between treatments within clones decreased with days after planting (DAP). There were no treatment differences for number of leaves, height, and root length at the end of cycle 2 (45 DAP) or cycle 3 (30 DAP). These results detail the extensive variation in clonal responses to leachate irrigation, along with the need and efficacy of using phyto-recurrent selection to choose superior genotypes.

Variation in copper and zinc tolerance and accumulation in 12 willow clones: implications for phytoextraction

“…Apart from genetic modifications, increasing the metal bioaccumulation capacity of a plant is primarily accomplished through the artificial selection of Salix clones; the selection of appropriate species or clones is crucial for achieving successful phytoremediation (Zalesny et al, 2007;Zalesny and Bauer, 2007a;2007b). Numerous studies have revealed a remarkable genotypic variability of the genus Salix in its ability to tolerate/accumulate heavy metals (Wang and Greger, 2004;Dos Santos Utmazian et al, 2007;Purdy and Smart, 2008;Zhivotovsky et al, 2010).…”

“…Salix comprises about 450 species as well as a large number of willow clones produced through breeding projects worldwide, which together provide a large number of plants to be screened for phytoremediation (Kuzovkina et al, 2004;Kuzovkina and Quigley, 2005). Owing to the high genetic variability in Salix, the use of clone selection has been proposed to find those best suited for phytoremediation purposes (Zalesny et al, 2007;Zalesny and Bauer, 2007b).…”

Exploring the metal phytoremediation potential of three Populus alba L. clones using an in vitro screening

“…To this purpose, we used an in vitro screening as an effective tool to exploit Populus alba L. clonal variability. This kind of study can represent a valuable method for the set-up of phyto-recurrent selection cycles, as proposed by Zalesny et al (2007), from which clones representing the right combination of high levels of trace element uptake and high productivity can be rapidly individuated and chosen for field tests. An in vitro screening reduces not only the growth period and the treatment time length of the plants but also the space required for the experiments.…”

Leaf number indicates salt tolerance of young seedling families of European aspen (Populus tremula L.) growing in different soils

“…These results suggest that leaf number of early stage seedlings can be used as an indicator of salt tolerance among young seedling families of P. tremula. Leaf number is an easily measured and non-destructive external index that enables comparison among plants grown in different environments (Zalesny et al 2007). Earlier studies have explored the relationship between leaf number, plant growth and stress tolerance (e.g., Kodani 1999, Pellegrino et al 2005), but our study is among the first to find a clear correlation among these factors.…”