Long-term field study on stabilization of contaminated wastes by growing clonally reproduced Silene vulgaris calamine ecotype

Abstract

Aims Pseudo-metallophyte Silene vulgaris frequently colonizes polluted areas. We investigated whether plants obtained under in vitro conditions can be used to form long-term communities on zinc-lead tailings rich in cadmium. To this end, we checked the species stabilization capacity and biochemical properties of the area subjected to long-term cultivation of a local S vulgaris ecotype. We focused on evaluation of its ability to accumulate trace metals (TMs) after 10-year cultivation period. Methods The calamine S. vulgaris ecotype was propagated in vitro and acclimatized to ex vitro conditions in a greenhouse. The plants were then replanted on plots created on the flotation settler heavily polluted with Zn, Pb and Cd. The capacity of trace metal accumulation in plant material was checked based on translocation (TF) and bio-concentration (BCF) factors. Nutrient, TMs content, and enzyme activity of substrate were determined after 1 and 10 years of cultivation and compared with the properties of bare flotation waste. Results Numerous plants obtained through vegetative in vitro propagation were planted in the field after a short hardening period. Cultivation of plant material obtained this way increased microbial activity, C concentration, and reduced TM contents in the substrate. TF calculated after the first season of S. vulgaris cultivation was similar for all metals and amounted to about 40%. After 10 years, it was the highest for Cd (50%). Independently of the experiment duration, BCF for Zn and Pb was <1, while for Cd it reached about 1.4 after 10 years for both shoots and roots. Conclusions The calamine S. vulgaris ecotype cloned in tissue culture proved useful material for stabilization of trace metal contaminated post-flotation wastes. Ten years of its cultivation in tailings rich in Zn, Pb and Cd contributed to humus layer formation and increase in microbial activity in the substrate. Thus, the beginning of soil formation was noticed in heavily polluted tailings.

Dual Role of Metallic Trace Elements in Stress Biology—From Negative to Beneficial Impact on Plants

“…Such conspicuous ambiguity of HMs categorization has led to general confusion regarding the significance of this term that has been recently subjected to a broad discussion. As a result of this consideration, the use of ‘trace element’ rather than ‘heavy metal’ seems to be more justified [14,15,16]. The present review fits well to this novel approach, since it is mostly focused on the profitable impact of the so-called HMs on plant organism.…”

“…However, it should not be forgotten that, despite many processes that regulate ions accumulation and transport in plants, when metal concentrations in the environment reach the critical level, the control mechanisms that are responsible for ion homeostasis in the protoplast may break down and the unrestricted influx of cations occurs. Among the plants colonizing highly polluted with heavy metals post-industrial waste heaps, excluder behaviour has been observed in specimens from metalliferous populations of Alyssum montanum [90] (Figure 4A), Dianthus carthusianorum [146] (Figure 4B), Potentilla arenaria [147] (Figure 4C), Scabiosa ochroleuca [147,148] (Figure 4D), or Silene vulgaris [16] (Figure 4E).…”

The Alleviation of Metal Stress Nuisance for Plants—A Review of Promising Solutions in the Face of Environmental Challenges

“…Recently, the potential of native metal-tolerant species for revegetation has been successfully verified for Agropyron smithii and Artemisia tridentate [ 51 ], Lygeum spartum [ 52 ], Achillea wilhelmsii [ 53 ], and Matthiola dagestanica and Draba stylaris [ 46 ]. The usefulness of metallophytes for revegetation and the phytostabilization of Zn-Pb rich soils in the Olkusz Ore-bearing Region, one of the biggest industrial areas in Poland, has been also proven in our earlier studies for Biscutella laevigata [ 49 , 54 ], Dianthus carthusianorum [ 49 ], Gypsophila fastigiata [ 55 ], and Silene vulgaris [ 56 ]. Undoubtedly, phytoremediation combined with the biological reclamation of destroyed or degraded ecosystems may constitute a new and safe opportunity for humans to positively interact with the environment.…”

Micropropagation and experimental field cultivation of Pulsatilla turczaninovii Kryl. et Serg. (Ranunculaceae)

“…Micropropagation techniques enable faster production of vegetative offspring in comparison with classic reproduction methods (Hanus-Fajerska et al 2019;Muszyńska et al 2018;Philips and Garda 2019). Culturing tissues and organs in vitro allows regenerating numerous micro-plantlets, from single donor plant or from its fragments.…”