In Vitro Lead Tolerance Testing in White Poplar Genotypes on Acidic Medium

Abstract

This study evaluates in vitro tolerance of white poplar genotypes to the presence of lead in an acidic rooting medium. Lead was supplemented in form of Pb(NO3)2, in the following concentrations: 0 M (Control), 10-6 M, 10-5 M, 10-4 M and 10-3 M. After four weeks of cultivation, the following characters were measured: number of roots, the length of the longest root, the shoot height, dry root mass and dry shoot mass, and parameters related to photosynthetic pigments: content of chlorophyll a, b, a+b, and of carotenoids in fresh mass, as well as chlorophyll a/b ratio. For further statistical analysis, tolerance indices by Turner and Marshal (TI) were calculated for each measured character. The strongest inhibitory effect was achieved on the medium with 10-4 M Pb(NO3)2, but the best differentiation between genotypes was achieved on the medium with 10-5 M Pb(NO3)2. The highest tolerance indices for the length of the longest root and shoot height had genotypes L-12 and LBM, and for root and shoot dry mass genotypes LCM and L-12. There were no significant differences between genotypes in tolerance indices by any of the examined photosynthetic parameters. The obtained results suggest that both low pH and the presence of citric acid as chelating agent improved evaluation of lead tolerance in comparison with the results obtained on media with standard pH and without citric acid in similar studies. In vitro tests on acidic medium with citric acid can efficiently differentiate examined genotypes for lead tolerance, which could be important for their use in phytoextraction projects, especially on acidic soils.

In vitro selection of drought-tolerant white poplar clones based on antioxidant activities and osmoprotectant content

“…That is why an understanding of the underlying drought tolerance mechanisms of plants is of essential importance, especially in forest tree species. Studies on the tolerance of white poplar to various abiotic and biotic factors have been conducted, such as: tolerance to acidity stress (Vuksanovićet al, 2019d); salinity (Sixto, 2005;Vuksanovićet al, 2019c;Zhang et al, 2019), drought (Yang et al, 2016), heavy metals (Kebert et al, 2017;Kovacěvićet al, 2020;Kebert et al, 2022b;Katanićet al, 2015;Fischerováet al, 2006). Polyethylene glycol has several advantages (Osmolovskaya et al, 2018) and allows a convenient way to assess the effects of drought on plant growth and development in controlled conditions (Vuksanovićet al, 2022).…”