Copper Uptake and Its Effects on Two Riparian Plant Species, the Native Urtica dioica, and the Invasive Fallopia japonica

Impact of trace elements on invasive plants: Attenuated competitiveness yet sustained dominance over native counterparts

Trace element pollution has emerged as an increasingly severe environmental challenge owing to human activities, particularly in urban ecosystems. In farmlands, invasive species commonly outcompete native species when subjected to trace element treatments, as demonstrated in experiments with individual invader-native pairs. However, it is uncertain if these findings apply to a wider range of species in urban soils with trace elements. Thus, we designed a greenhouse experiment to simulate the current copper and zinc levels in urban soils (102.29 mg kg-1 and 148.32 mg kg-1, respectively). The experiment involved four pairs of invasive alien species and their natural co-existing native species to investigate the effects of essential trace elements in urban soil on the growth and functional traits of invasive and native species, as well as their interspecific relationship. The results showed that adding trace elements weakened the competitiveness of invasive species. Nonetheless, trace element additions did not change the outcome of competition, consistently favoring invasion successfully. Under trace element addition treatments, invasive species and native species still maintained functional differentiation trend. Furthermore, the crown area, average leaf area and leaf area per plant of invasive species were higher than those of native species by 157 %, 177 % and 178 % under copper treatment, and 194 %, 169 % and 188 % under zinc treatment, respectively. Additionally, interspecific competition enhanced the root growth of invasive species by 21 % with copper treatment and 14 % with zinc treatment. The ability of invasive species to obtain light energy and absorb water and nutrients might be the key to their successful invasion.

Evaluation of the Main Macro-, Micro- and Trace Elements Found in Fallopia japonica Plants and Their Traceability in Its Honey: A Case Study from the Northwestern and Western Part of Romania

Fallopia japonica (Japanese knotweed, Reynoutria japonica or Polygonum cuspidatum) is considered an extremely invasive plant worldwide and a bioindicator of heavy metals. Yet, its potential as a crop for honeybees is still underevaluated. This study employs atomic absorption spectrometry to quantitatively analyze the concentration of macro-elements, namely, calcium (Ca), potassium (K) and magnesium (Mg); micro-elements, such as copper (Cu), iron (Fe), manganese (Mn) and selenium (Se); and trace elements, i.e., cadmium (Cd), chromium (Cr), nickel (Ni) and lead (Pb) in different anatomic parts of Fallopia japonica (FJ) plants (roots, rhizomes, stems, leaves) and their traceability into honey. This research encompasses a thorough examination of samples collected from the northwestern and western part of Romania, providing insights into their elemental composition. The results showed that the level of trace elements decreases in terms of traceability in honey samples (Pb was not detected in any of the analyzed samples, while Cd had a minimum content 0.001 mg/kg), ensuring its quality and health safety for consumption. Moreover, the data generated can function as a valuable resource to explore the plant's positive eco-friendly impacts, particularly in relation to its honey.

A synthesis of anthropogenic stress effects on emergence-mediated aquatic-terrestrial linkages and riparian food webs

Anthropogenic stress alters the linkage between aquatic and terrestrial ecosystems in various ways. Here, we review the contemporary literature on how alterations in aquatic systems through environmental pollution, invasive species and hydromorphological changes carry-over to terrestrial ecosystems and the food webs therein. We consider both the aquatic insect emergence and flooding as pathways through which stressors can propagate from the aquatic to the terrestrial system. We specifically synthesize and contextualize results on the roles of pollutants in the emergence pathway and their top-down consequences. Our review revealed that the emergence and flooding pathway are only considered in isolation and that the overall effects of invasive species or pollutants on food webs at the water-land interface require further attention. While very few recent studies looked at invasive species, a larger number of studies focused on metal transfer compared to pesticides, pharmaceuticals or PCBs, and multiple stress studies up to now left aquatic-terrestrial linkages unconsidered. Recent research on pollutants and emergence used aquatic-terrestrial mesocosms to elucidate the effects of aquatic stressors such as the mosquito control agent Bti, metals or pesticides to understand the effects on riparian spiders. Quality parameters, such as the structural and functional composition of emergent insect communities, the fatty acid profiles, yet also the composition of pollutants transferred to land prove to be important for the effects on riparian spiders. Process-based models including quality of emergence are useful to predict the resulting top-down directed food web effects in the terrestrial recipient ecosystem. In conclusion, we present and recommend a combination of empirical and modelling approaches in order to understand the complexity of aquatic-terrestrial stressor propagation and its spatial and temporal variation.

Physiological and Biochemical Properties of Cotton Seedlings in Response to Cu2+ Stress

Copper(II) (Cu²⁺) is essential for plant growth and development. However, high concentrations are extremely toxic to plants. We investigated the tolerance mechanism of cotton under Cu²⁺ stress in a hybrid cotton variety (Zhongmian 63) and two parent lines with different Cu²⁺ concentrations (0, 0.2, 50, and 100 μM). The stem height, root length, and leaf area of cotton seedlings had decreased growth rates in response to increasing Cu²⁺ concentrations. Increasing Cu²⁺ concentration promoted Cu²⁺ accumulation in all three cotton genotypes' roots, stems, and leaves. However, compared with the parent lines, the roots of Zhongmian 63 were richer in Cu²⁺ and had the least amount of Cu²⁺ transported to the shoots. Moreover, excess Cu²⁺ also induced changes in cellular redox homeostasis, causing accumulation of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA). Conversely, antioxidant enzyme activity increased, while photosynthetic pigment content decreased. Our findings indicated that the hybrid cotton variety fared well under Cu²⁺ stress. This creates a theoretical foundation for the further analysis of the molecular mechanism of cotton resistance to copper and suggests the potential of the large-scale planting of Zhongmian 63 in copper-contaminated soils.

Ionome of Lithuanian Populations of Purple Loosestrife (Lythrum salicaria) and Its Relation to Genetic Diversity and Environmental Variables

Fifteen riparian populations of Lithuanian Lythrum salicaria were assessed for leaf macronutrient, micronutrient and non-essential element concentrations and compared to the former obtained molecular data at amplified fragment length polymorphism (PLP.AFLP) loci. Inductively coupled plasma mass spectrometry was used to profile the contents of 12 elements in the leaves. The leaf nutrient concentrations were within normal ranges for growth and development and heavy metal concentrations did not reach toxic levels. The concentrations of macroelements such as nitrogen, potassium, calcium and magnesium were in the range of 23,790–38,183; 7327–11,732; 7018–12,306; and 1377–3183 µg/g dry mass (d. m.), respectively; the concentrations of micronutrients such as sodium, iron, zinc and copper varied in the ranges of 536–6328; 24.7–167.1; 10.88–26.24; and 3.72–5.30 µg/g d. m., respectively, and the concentrations of non-essential elements such as lead, nickel, chromium, and cadmium were in the intervals of 0.136–0.940; 0.353–0.783; 0.207–0.467; and 0.012–0.028 µg/g d. m., respectively. When comparing the maximum and minimum values for site elements of L. salicaria, the concentration of N varied by 1.6, K—1.6, Ca—1.8, Mg—2.3, Na—6.1, Fe—6.8, Zn—2.4, Cu—1.5, Pb—6.9, Ni—2.2, Cr—2.2, and Cd—2.3 times. The coefficient of variation (CV) of element concentrations in sites was moderate to large: N—15.4%, K—14.3%, Ca—18.6%, Mg—24.8%, Na—50.7%, Fe—47.0%, Zn—24.9%, Cu—14.5%, Pb—57.1%, Ni—30.11%, Cr—26.0%, and Cd—38.6%. Lythrum salicaria populations growing near regulated riverbeds were characterized by significantly (p < 0.05) lower concentrations of Ca and Mg, and significantly (p < 0.05) higher concentrations of N, K, Fe, Na, Ni, Cr and Cd. The PLP.AFLP was negatively correlated with concentrations of N, Na, Fe, Ni, Cr, and Cd. The L. salicaria population with the lowest leaf N and Na concentration showed the highest genetic polymorphism (PLP.AFLP = 65.4%), while the least polymorphic population (PLP.AFLP = 35.0%) did not show extreme concentrations of either element. In conclusion, our elemental analysis of L. salicaria populations showed that ionomic parameters are related to genomic parameters, and some habitat differences are reflected in the ionomes of the populations.