Helianthus petiolaris: a novel native aromatic plant species with potential use in phytostabilizatyon of metals contaminated areas

SARAN, A; FERNANDEZ, L; IMPERATO, V; THIJS, S; VANGRONSVELD, J; MERINI, LJ

Novi Sad

Conferencia; 15th International Phytotechnology Conference; 2018

International Phytoremediation Society

Environmental pollution by metals has become a serious problem in the world. Its rising concentrations in different environments, due to industrialization and globalization, generate environmental stresses that will limit land use in the upcoming years (Govindasamy et al., 2011; McGrath et al., 2002). In this context aromatic plant species used for essential oils production may be a suitable alternative to phytostabilize and phytomanage contaminated lands. The aim of this work was to assess the potential use of Helianthus petiolaris, a novel metal tolerant native aromatic plant from Argentina, to phytostabilize metal contaminated soils. In this way, an open microcosm experiment was carried out in greenhouse. Seedlings of H. petiolaris and H. annuus (positive control) were transplanted to bottom closed pots containing 1.5 Kg of soil spiked with different concentrations of cadmium and lead (100, 50, 10 mg.Kg-1 of Cd and 1000, 500, 100 mg.Kg-1 of Pb) and an aged Pb contaminated soil, obtained from an abandoned shooting range area. During the experiment, the plants physiological parameters such as shoots length, number of leaves, flowering, total chlorophyll, chlorophyll A/B and carotenoids were monitored. After 90 days, the plants were harvested and the impact of the metals on their final biomass (fresh and dry weight, root and stem length) was also measured. H. petiolaris was able to grow in soils at all the different concentrations of Pb assayed and in those contaminated with 50 and 10 mg.Kg-1 of Cd, where no significant differences were found in the physiological parameters tested. During the first 27 days of exposure to the different treatments, chlorophyll monitoring showed a fluctuating behaviour, followed by a stabilization period, except in presence of 100 mg.Kg-1 of Cd, where the plants died after the adaptation period. The same fluctuation in chlorophyll content was observed in H. annuus during the first 22 days of exposure. Data distribution obtained was statistically analysed by nonmetric multidimensional scaling (NMDS) using Euclidean dissimilarity matrix. In turn, Pb and Cd concentrations in soil and different plant tissues were assessed by Plasma Inductive Spectroscopy (ICP-OES). The influence of each treatment on the microbial diversity of root, rhizoplane and soil associated microbiomes was also assessed by amplification of the 16S-23S rRNA automated intergenic transcribed spacers (ARISA). The number of peaks in the ARISA profiles, the range of peak size (width of the profile) and the reproducibility of results were used as indices to evaluate the metal effects on the bacterial community. Furthermore, over 100 cultivable rhizoplane and endophytic tolerant bacteria were isolated and identified (by 16S rRNA sequencing) in order to constitute a bank of metal tolerant bacteria for future inoculant formulations.