Technological Eco-Innovations for the Quality Control and the Decontamination of Polluted Waters and Soils

The Special Issue “Technological Eco-Innovations for the Quality Control and the Decontamination of Polluted Waters and Soils” deals with the most recent research activities carried out at lab and field scale on eco-sustainable tools for the remediation of contaminated environmental substrates. It is particularly devoted to highlight the relevance of biological organisms (plants, microbes, algae) to assess the chemical contamination in water and soil and to remediate such matrices from the pollution caused by the human activities. Therefore, bioremediation is a primary focus of most of the articles published within the present Special Issue. Bioremediation is a promising environmentally friendly technology to deal with the chemical pollution in different ecosystem compartments and its integration with the traditional approaches might represent

Susceptibility to Melampsora leaf rust of poplar clones from diverse genetic backgrounds: effects on photochemistry and water relations

The selection of resistant genotypes is the most appropriate approach in the prevention of the reduction of biomass and mortality caused by rust infection in poplar plantations. Thus, it is pertinent that we improve our understanding of the consequences that this fungal disease has on leaf physiology. Here, we studied the susceptibility to Melampsora rust in three different poplar clones of commercial interest: Lux clone - Populus deltoides Batr. (cottonwood) and Luisa Avanzo and Adige clones - both Populus × canadensis Mönch. The most susceptible clone to the infection was L. Avanzo whereas Lux and especially Adige were only slightly affected. The propagation of the disease was very rapid in L. Avanzo; their leaves showed a high incidence and severity of the disease in early and advanced stages of infection as was clearly evidenced by the degree of infection. Infected leaves of L. Avanzo were shown to have drought impaired water relations during summer as reflected by the marked decline in the relative water content (RWC). Chlorophyll fluorescence imaging revealed heterogeneity of the effect of the pathogen in the leaves, and areas with pustules showed low maximum quantum yield (Fv/Fm) and PSII quantum yield (?PSII) values, indicative of strong photoinhibition. In L. Avanzo, with a greater pustule density, rust provoked a decline in whole leaf photochemistry as indicated by Fv/Fm and photochemical reflectance index (PRI) results. Leaf structural parameters were not affected by the disease but results in L. Avanzo and Lux showed higher leaf mass per area (LMA) and higher leaf density (D) indicating an adaptation to increasing summer drought. In all clones, the effect of the pathogen was reflected in lower leaf chlorophyll content

Bismuth exposure affects morpho-physiological performances and the ionomic profile in garden cress (Lepidium sativum L.) plants

Environmental pollution caused by heavy metals has long been considered a relevant threat to ecosystem survival and human health. The use of safer substitutes for the most toxic heavy metals in many industrial applications is discussed as a potential way to face this issue. In this regard, Bi has been proposed for replacing Pb in several production processes. However, few literature records reported on the effects of Bi on living organisms, particularly on plants. In this study, garden cress (Lepidium sativum L.) plants were exposed to different concentrations of Bi nitrate added to soil in growth chambers for 21 days. Results evidenced the toxic effect of Bi on shoot growth, regardless of the Bi nitrate concentration in the soil, paralleled by a similar reduction in the chlorophyll and carotenoid content, a decrease in the nitrogen balance index values, and an impairment of the photosynthetic machinery evaluated by chlorophyll fluorescence image analysis. The presence of Bi in the soil was shown to affect element accumulation in roots and translocation to shoots, with micronutrient content particularly reduced in the leaves of Bi-treated plants. A dose-dependent plant accumulation of Bi to metal concentration in the soil was observed, even if very low metal bioconcentration ability was highlighted. The reduced Bi translocation from roots to shoots in plants exposed to increasing Bi concentrations in the soil is discussed as a possible defense mechanism likely associated with the observed increase of anthocyan and flavonol contents and the activation of photoprotection mechanisms preventing higher damages to the photosynthetic apparatus

Ruthenium(II)-Tris-pyrazolylmethane Complexes Inhibit Cancer Cell Growth by Disrupting Mitochondrial Calcium Homeostasis

While ruthenium arene complexes have been widely investigated for their medicinal potential, studies on homologous compounds containing a tridentate tris(1-pyrazolyl)methane ligand are almost absent in the literature. Ruthenium(II) complex 1 was obtained by a modified reported procedure; then, the reactions with a series of organic molecules (L) in boiling alcohol afforded novel complexes 2-9 in 77-99% yields. Products 2-9 were fully structurally characterized. They are appreciably soluble in water, where they undergo partial chloride/water exchange. The antiproliferative activity was determined using a panel of human cancer cell lines and a noncancerous one, evidencing promising potency of 1, 7, and 8 and significant selectivity toward cancer cells. The tested compounds effectively accumulate in cancer cells, and mitochondria represent a significant target of biological action. Most notably, data provide convincing evidence that the mechanism of biological action is mediated by the inhibiting of mitochondrial calcium intake

Environmental restoration of metal-contaminated soils

The growing industrialization of the last two centuries has improved life to a great extent in the countries where it occurred [...

Evaluation of Multiple Responses Associated with Arsenic Tolerance and Accumulation in Pteris vittata L. Plants Exposed to High As Concentrations under Hydroponics

Chinese brake fern (Pteris vittata L.) is recognized as an arsenic hyperaccumulating plant. Mechanisms underlying this capability and the associated hypertolerance have been described even if not completely elucidated. In this study, with the aim to expand the knowledge on the matter, an experimental trial was developed to investigate an array of responses, at the morphological, physiological, and biochemical level, in P. vittata plants exposed to high As concentrations in a long-term experiment under hydroponics. Results confirmed the ability of fern plants to both tolerate and accumulate a remarkable amount of As, especially in fronds. Notably, in As-treated plants, a far higher As content was detected in young fronds compared to old fronds, with bioaccumulation (BCF) and translocation (Tf) factors in accordance. At the biochemical level, As treatment affected macro and micronutrient, thiol, and phytochelatin concentrations in fronds of treated plants differently than that of the control. Physiological measurements accounted for a reduction in the photosynthetic activity of As-treated plants in the absence of visual symptoms of damage. Overall, the observed As tolerance and accumulation processes were discussed, evidencing how young fronds developed during As treatment maintain their physiological status while accumulating a high As content. Such indications could be very useful to improve the effective utilization of this plant species for phytofiltration of As-polluted water

Morpho-Physiological and Metal Accumulation Responses of Hemp Plants (Cannabis Sativa L.) Grown on Soil from an Agro-Industrial Contaminated Area

Hemp is a promising plant for phytomanagement. The possibility to couple soil restoration to industrial crop cultivation makes this plant attractive for the management of contaminated sites. In this trial, Cannabis sativa L. plants were grown in a greenhouse on soils from two sites of “Valle del Sacco” (Lazio Region, Italy), a wide area contaminated by agro-industrial activities. One site was representative of moderate and diffuse metal(loid) multi-contamination, above the Italian concentration limit for agriculture (MC—moderately contaminated). The second site showed a metal(loid) content below the aforementioned limit, as a typical background level of the district (C—control). After 90 days, biometric and physiological parameters revealed satisfactory growth in both soil types. MC-grown plants showed a slight, but significant reduction in leaf area, root, and leaf biomass compared with C-grown plants. Chlorophyll content and chlorophyll fluorescence parameters, namely the quantum yield of primary photochemistry (Fv/Fm) and the Performance Index (PIABS), confirmed the good physiological status of plants in both soils. Metal(loid) analyses revealed that As, V, and Pb accumulated only in the roots with significant differences in MC- and C-grown plants, while Zn was found in all organs. Overall, preliminary results showed a satisfactorily growth coupled with the restriction of toxic metal translocation in MC-grown hemp plants, opening perspectives for the phytomanagement of moderately contaminated areas

Catechol-Loading Nanofibrous Membranes for Eco-Friendly Iron Nutrition of Plants

Modern agriculture requires more efficient and low-impact products and formulations than traditional agrochemicals to improve crop yields. Iron is a micronutrient essential for plant growth and photosynthesis, but it is mostly present in insoluble forms in ecosystems so that it is often limiting for plants. This study was aimed at combining natural strategies and biodegradable nanostructured materials to create environmentally friendly and low-toxic bioactive products capable of both supplying iron to Fe-deficient plants and reducing the impact of agricultural products on the environment. Consequently, free-standing electrospun nanofibrous polycaprolactone/polyhydroxybutyrate thin membranes loaded with catechol (CL-NMs) as an iron-chelating natural agent (at two concentrations) were fabricated on purpose to mobilize Fe from insoluble forms and transfer it to duckweed (Lemna minor L.) plants. The effectiveness of CL-NMs in providing iron to Fe-deficient plants, upon catechol release, tested in duckweeds grown for 4 days under controlled hydroponic conditions, displayed temporal variations in both photosynthetic efficiency and biometric parameters measured by chlorophyll fluorescence and growth imaging. Duckweeds supplied with CL-NMs hosting higher catechol concentrations recovered most of the physiological and growth performances previously impaired by Fe limitation. The absence of short-term toxicity of these materials on duckweeds also proved the low impact on ecosystems of these products

Morpho-physiological and molecular responses of Lepidium sativum L. seeds induced by bismuth exposure

Bismuth (Bi) is considered a “green metal” as its toxicity has been reported to be lower than other metals, particularly lead. Even though the low presence in the environment, an increase of Bi concentrations in soil and wastewater is predictable due to its enhanced uses for many industrial and medical applications. Therefore, given the little literature on the matter, particularly in plants, information on the effects of Bi on living organisms is needed. In this study, seeds of garden cress (Lepidium sativum L.), a model plant for ecotoxicological assays (OECD), were exposed to increasing Bi concentrations (0 to 485 mg L−1 Bi(NO3)3·5H2O in deionised water) in petri plates. After 72 h, the percent germination index (GI%) revealed no effects at the lowest Bi concentrations, while a slight toxicity occurred at 242 and 485 mg L−1 Bi nitrate. A significant reduction of the root length was observed in Bi-treated seedlings, especially at the highest Bi concentrations. Consistently, the Alkaline Comet Assay revealed a genotoxic effect induced by Bi exposure in garden cress seedlings. A Bi concentration-dependent metal accumulation in plantlets was also observed, with a Bi concentration higher than 1200 mg kg−1 found in plantlets at the highest Bi concentration assayed. The toxicity effects observed in the study were discussed, as contribution to the expansion of knowledge on Bi ecotoxicity and genotoxicity in plants