The expanding development of graphene-based materials (GBMs) requires immediate and balanced environmental assessment balancing two key areas: investigating the risk of graphene oxide toxicity to ecosystems and evaluating GBMs’ potential to act as solutions for challenges like heavy metal stress mitigation. This study analyzed the effects of reduced graphene oxide (rGO) on copper (Cu) and nickel (Ni) toxicity in Lemna minor. Our findings reveal that rGO’s protective effects are metal-specific. L. minor demonstrated significant sensitivity to nickel, but rGO offered no mitigation; growth parameters, pigment content, and nickel accumulation showed no significant improvements with rGO co-exposure compared to Ni-plants. This suggests that rGO does not enhance L. minor’s ability to tolerate or absorb nickel, especially after 14 days (T14). In contrast, rGO showed a partially protective effect against copper toxicity. At T14, the presence of rGO significantly improved plant performance under copper stress, resulting in a 17% increase in biomass, a 19% increase in relative growth rate, and enhanced pigment content, including a 40% increase in chlorophyll when compared to Cu-plants. The protective effect of rGO was directly tied to a 37% reduction in copper accumulation, providing strong evidence that rGO reduces copper’s bioavailability, thereby limiting plant uptake. The divergent effects on Cu and Ni uptake suggest differing affinities of these metals for rGO. Future research, including large-scale experiments with various GBMs and Lemna clones, is crucial to fully assessing their phytoremediation potential.

Lemnaceae taxonomy is challenged by the particular morphology of these tiny free-floating angiosperms. Although molecular taxonomy has helped clarify the phylogenetic history of this family, some inconsistency with morphological data leads to frequent misclassifications in the genus Lemna. Recently, the finding that Lemna japonica is an interspecific hybrid between Lemna minor and Lemna turionifera provided a clear explanation for one such taxonomic question. Here we demonstrated that L. minor is also capable of hybridizing with Lemna gibba, generating a cryptic but widespread taxon in the Mediterranean area. The nothotaxon Lemna ×mediterranea is described and compared with clones of the putative parental species L. minor and L. gibba. Genetic analysis by nuclear and plastid markers, as well as genome size measurement, revealed that two different cytotypes, diploid and triploid, originated by at least two independent hybridization events. Despite high overall similarity, morphometrical, physiological, and biochemical analyses showed an intermediate position of L. ×mediterranea between its parental species in most qualitative and quantitative characters, and also separation of the two hybrid cytotypes by some criteria. These data provide evidence that hybridization and polyploidization, driving forces of terrestrial plant evolution, contribute to duckweed genetic diversity and may have shaped the phylogenetic history of these mainly asexual, aquatic plants.

In modern agricultural production, cattle manure waste recovery is considered as a sustainable approach to agricultural waste management, reducing environmental pollution and chemical fertilizer use. This study aimed to investigate the effects of manure and digestate derived from a pilot-scale livestock waste-recycling system, in combination with a low copper concentration as a fungicide, on the physiological response of lettuce cv Rufus (Lactuca sativa L.) plants and the associated soil microbiome. A five-week microcosm experiment was conducted in a greenhouse under environmental conditions. Lettuce plant performance was assessed in terms of biomass, leaf area index, photosynthetic activity, chlorophyll measurements, lipid peroxidation, total phenolic content, and nutrient uptake. The results suggested that incorporating digestate into the potting soil mix significantly enhanced crop yields compared to the control and manure treatments. The soil microbial activity increased in the presence of fertilizers, improving the soil chemical and biological properties. The addition of copper negatively affected the growth and physiological performance of the lettuce plants under both the control and manure-treated conditions, except for those grown in the presence of digestate, where copper accumulation was reduced. These findings highlight the potential of growing horticultural crops using organic fertilization through livestock waste anaerobic digestate, establishing a waste-to-food recycling system.

Duckweeds are aquatic plants often used in phytotoxic studies for their small size, simple structure, rapid growth, high sensitivity to pollutants and facility of maintaining under laboratory conditions. In this paper, induced phytotoxic effects were investigated in Lemna minor and Lemna minuta after exposition to silver nitrate (AgNO3) and silver nanoparticles stabilized with sodium citrate and L-Cysteine (AgNPs-Cit-L-Cys) at different concen-trations (0, 20 and 50 mg/L) and times (7 and 14 days). Lemna species responses were evaluated analyzing plant growth (mat thickness, fresh and dry biomass, relative growth rate - RGR) and physiological parameters (chlorophyll - Chl, malondialdehyde - MDA, ascorbate peroxidase - APX and catalase -CAT). Ag content was measured in the fronds of the two Lemna species by inductively coupled plasma optical emission spectrometry. AgNO3 and AgNPs-Cit-L-CYs produced phytotoxic effects on both duckweed species (plant growth and Chl reduction, MDA increase) that enhanced in response to increasing concentrations and exposure times. AgNPs-Cit-L-Cys caused much less alteration in the plants compared to AgNO3 suggesting that the presence of bifunc-tionalized AgNPs-Cit-L-Cys have a reduced phytotoxic effect as compared to Ag+ released in water. Based on the physiological performance, L. minuta plants showed a large growth reduction and higher levels of chlorosis and stress in respect to L. minor plants, probably due to greater Ag+ ions accumulation in the fronds. Albeit with some differences, both Lemna species were able to uptake Ag+ ions from the aqueous medium, especially over a period of 14 days, and could be considered adapt as phytoremediation agents for decontaminating silver ion-polluted water.

The objective of this study was to investigate the combined effects of elevated CO2 and cadmium (Cd) treatments on growth, photosynthetic efficiency and phytoremediation ability in Lemna minor L. Plants of L. minor were exposed to different Cd concentrations (0, 1.5, 2.5 and 5 mg L(-1) Cd) for periods of 24, 48 and 72 h at ambient (AC) and at elevated (EC) CO2 (350 and 700 ppm, respectively). Cadmium concentration, bioconcentration factor, enzyme activities and thiols content enhanced in plants with the increase of Cd treatments, time of exposure and at both CO2 levels. Glutathione levels increased only at AC. Growth, photosynthetic and chlorophyll fluorescence parameters, and the reduced glutathione to oxidized glutathione ratio declined in plants with increasing exposure time, Cd treatments and at both CO2 levels. Our results suggested that the alleviation of toxicity, at low Cd doses, observed in L. minor grown at EC is dependent on both increased photosynthesis and an enhanced antioxidant capacity.

Metal pollution in waters and soils is a major environmental and human health problem. Cadmium (Cd2+) is a heavy metal displaying toxic effects in plants. In this work we studied the potentiality of Lemna minor, a monocotyledonous aquatic macrophyte, to phytoremediate cadmium-polluted waters. The plants were exposed to different cadmium concentrations 0, 13, 22 and 46μM CdSO4 for a period of 24, 48 and 72 hours. Relative growth rates (RGR), bioconcentration factor (BCF), tolerance index (Ti), cadmium uptake in whole plant and maximum efficiency of PSII (Fv/Fm) were measured under controlled climate conditions. RGR, Ti and Fv/Fm declined with increasing exposure time and cadmium concentrations, while the BCF and cadmium uptake showed an opposite behavior. Data analysis of RGR, BCF, Tiand FV/FM indicates that L. minor maintains a good capacity of growth, metal bioconcentration, tolerance and efficiency of PSII up to 48h in plants exposed to 13 and 22μM CdSO4. Our results exhibited that L. minor is a good cadmium accumulator and is able to remediate Cd-polluted waters, especially at low Cd concentrations.

Transgene escape risks are evaluated by assessing the frequency of transgenic hybrids within populations sexually compatible with those genetically modified. We examined the pollen-mediated transgene flow among lettuce varieties in Italy. Transgenic 'Luxor' lines harboured the arabidopsis KNAT1 gene, which caused leaf trait alterations, and the bacterial NPTII gene for resistance to kanamycin. Donor homozygous lines (KNAT1:NPTII/KNAT1:NPTII) were used in two trials: in glasshouse, 'Luxor' transgenic and conventional plants were spaced at 15 cm; in field, a transgenic 'Luxor' donor island was set up and surrounded by 10 pollen receiver varieties sited at 0.5, 11 and 22 m. Progenies of recipient cultivars were screened by kanamycin assays, leaf alterations, transgene transcription and integrity. The out-crossing rate (OCR) was calculated as the frequency of KNAT1:NPTII/- and delta KNAT1:NPTII/- genotypes because KNAT1 impair (indicated with delta) was observed to vary from the 0.03% to 0.36%. Indoor, 'Luxor' intra-varietal OCR was 0.41 +/- 0.11%; outdoor, the average inter-varietal OCR was 0.49%, 0.071% and 0.035% for plants at 0.5, 11 and 22 m, respectively.

The Italian Ministry of Public Works has funded a study aimed at assessing the technical feasibility and financial viability of a disalination plant to be implemented in Agrigento, Sicily. The plant, with a design production capacity of 40,000 m3 and an estimated cost of € 120 million, will serve 19 municipalities of the Agrigento province with a total population of 300,000. The study has reviewed all the technologies presently available on the market. An indepth analysis has been carried out on multi-flash and osmosis based processes. For both technologies implementation and operational cost have been assessed. The study has placed particular emphasis on the possible solutions enabling: energy saving; power co-generation (multi-flashes); renewable energy sources (reverse osmosis). The study has also explored the potential for the production of Aeolian energy and identified solutions ensuring from 20,000 kW to 30,000 kW. Each solution has taken into account current town planning regulations, environmental impacts, possible mitigation measures, pre-treatment requirements, water in-take works, production waste dumping structures, as well as operation and management problems to be tackled. Implementation and operation costs have also been estimated. The study provides an assessment of the administrative, institutional and financial viability of the proposed solutions, in compliance with regional plans and regulations. Econometric models have been developed in order to enable project financing and water tariffs to be established.

Phragmites australis is a rhizomatous plant of the Poaceae family with the widest geographical distribution of any flowering plant. It often invades wetlands where with its vigorous propagation can outcompete rare plant communities, On the other hand, invasion by this species in water polluted habitats seems to be beneficial and the decline of its population in some areas, such as the lake Trasimeno in Italy, is accompanied by enhanced water pollution. In fact, Phragmites can thrive in shallow and almost stagnant water, where few others species can survive, because its dense and vertically extended rhizome mat, anchored to the shore, takes up nutrients (nitrogen and phosphorus). It has been hypothesised that this habit favours the degradation of some chemical compounds in the rhizome and the removal of heavy metals from the water, The capacity to oxygenate the rhizome is at the basis of these activities. Thus, Phragmites has features particularly relevant to its potential use to remediate the contamination of wetlands by agriculture run-off, Actually, it has been already included in constructed wetland to clean civil and industrial wastewater with a high load of organic pollutants. In this paper we will analyse and integrate with new results the current knowledge on the biological characteristics of this species. We will also analyse how it interacts with the environment.

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