Stress Response to Climate Change and Postharvest Handling in Two Differently Pigmented Lettuce Genotypes: Impact on Invasion and Mycotoxin Production.

Many species of are important pathogens that cause plant diseases and postharvest rots. They lead to significant economic losses in agriculture and affect human and animal health due to their capacity to produce mycotoxins. Therefore, it is necessary to study the factors that can result in an increase in .

Traffic restrictions during COVID-19 lockdown improve air quality and reduce metal biodeposition in tree leaves.

The coronavirus disease (COVID-19) has had a great global impact on human health, the life of people, and economies all over the world. However, in general, COVID-19´s effect on air quality has been positive due to the restrictions on social and economic activity. This study aimed to assess the impact on air quality and metal deposition of actions taken to reduce mobility in 2020 in two different urban locations.

Photoprotective compounds as early markers to predict holm oak crown defoliation in declining Mediterranean savannahs.

Dehesas, human-shaped savannah-like ecosystems, where the overstorey is mainly dominated by the evergreen holm oak (Quercus ilex L. subsp. ballota (Desf.

Successful remediation of soils with mixed contamination of chromium and lindane: Integration of biological and physico-chemical strategies.

Soils contaminated by organic and inorganic pollutants like Cr(VI) and lindane, is currently a main environmental challenge. Biological strategies, such as biostimulation, bioaugmentation, phytoremediation and vermiremediation, and nanoremediation with nanoscale zero-valent iron (nZVI) are promising approaches for polluted soil health recovery. The combination of different remediation strategies might be key to address this problem.

Long-term phytomanagement with compost and a sunflower - Tobacco rotation influences the structural microbial diversity of a Cu-contaminated soil.

At a former wood preservation site contaminated with Cu, various phytomanagement options have been assessed in the last decade through physicochemical, ecotoxicological and biological assays. In a field trial at this site, phytomanagement with a crop rotation based on tobacco and sunflower, combined with the incorporation of compost and dolomitic limestone, has proved to be efficient in Cu-associated risk mitigation, ecological soil functions recovery and net gain of economic and social benefits. To demonstrate the long-term effectiveness and sustainability of phytomanagement, we assessed here the influence of this remediation option on the diversity, composition and structure of microbial communities over time, through a metabarcoding approach.

Life after Harvest: Circadian Regulation in Photosynthetic Pigments of Rocket Leaves during Supermarket Storage Affects the Nutritional Quality.

Vegetables, once harvested and stored on supermarket shelves, continue to perform biochemical adjustments due to their modular nature and their ability to retain physiological autonomy. They can live after being harvested. In particular, the content of some essential nutraceuticals, such as carotenoids, can be altered in response to environmental or internal stimuli.

Can Parietin Transfer Energy Radiatively to Photosynthetic Pigments?

The main role of lichen anthraquinones is in protection against biotic and abiotic stresses, such as UV radiation. These compounds are frequently deposited as crystals outside the fungal hyphae and most of them emit visible fluorescence when excited by UV. We wondered whether the conversion of UV into visible fluorescence might be photosynthetically used by the photobiont, thereby converting UV into useful energy.

Diversity of winter photoinhibitory responses: a case study in co-occurring lichens, mosses, herbs and woody plants from subalpine environments.

Winter evergreens living in mountainous areas have to withstand a harsh combination of high light levels and low temperatures in wintertime. In response, evergreens can activate a photoprotective process that consists of the downregulation of photosynthetic efficiency, referred to as winter photoinhibition (WPI). WPI has been studied mainly in woody evergreens and crops even when, in many instances, other functional groups such as lichens or bryophytes dominate in alpine and boreal habitats.

Autofluorescence: Biological functions and technical applications.

Chlorophylls are the most remarkable examples of fluorophores, and their fluorescence has been intensively studied as a non-invasive tool for assessment of photosynthesis. Many other fluorophores occur in plants, such as alkaloids, phenolic compounds and porphyrins. Fluorescence could be more than just a physicochemical curiosity in the plant kingdom, as several functional roles in biocommunication occur or have been proposed.

Ecophysiological roles of abaxial anthocyanins in a perennial understorey herb from temperate deciduous forests.

Accumulation of abaxial anthocyanins is an intriguing leaf trait particularly common among deeply shaded understorey plants of tropical and temperate forests whose ecological significance is still not properly understood. To shed light on it, possible ecophysiological roles of abaxial anthocyanins were tested in the perennial understorey herb of temperate deciduous forests Saxifraga hirsuta, chosen as a model species due to the coexistence of green and anthocyanic leaves and the presence of an easily removable lower anthocyanic epidermis. Anthocyanins accumulated during autumn, which temporally matched the overstorey leaf fall.

Does age matter under winter photoinhibitory conditions? A case study in stems and leaves of European mistletoe (Viscum album).

European mistletoe (Viscum album L.) is a hemiparasitic plant with perennial leaves and photosynthetic stems easily discernible according to their age. These properties make V.

Activation of photoprotective winter photoinhibition in plants from different environments: a literature compilation and meta-analysis.

Overwintering plants face a pronounced imbalance between light capture and use of that excitation for photosynthesis. In response, plants upregulate thermal dissipation, with concomitant reductions in photochemical efficiency, in a process characterized by a slow recovery upon warming. These sustained depressions of photochemical efficiency are termed winter photoinhibition (WPI) here.

Side-effects of domestication: cultivated legume seeds contain similar tocopherols and fatty acids but less carotenoids than their wild counterparts.

Background: Lipophilic antioxidants play dual key roles in edible seeds (i) as preservatives of cell integrity and seed viability by preventing the oxidation of fats, and (ii) as essential nutrients for human and animal life stock. It has been well documented that plant domestication and post-domestication evolution frequently resulted in increased seed size and palatability, and reduced seed dormancy. Nevertheless, and surprisingly, it is poorly understood how agricultural selection and cultivation affected the physiological fitness and the nutritional quality of seeds.

Evidence for the absence of enzymatic reactions in the glassy state. A case study of xanthophyll cycle pigments in the desiccation-tolerant moss Syntrichia ruralis.

Desiccation-tolerant plants are able to withstand dehydration and resume normal metabolic functions upon rehydration. These plants can be dehydrated until their cytoplasm enters a 'glassy state' in which molecular mobility is severely reduced. In desiccation-tolerant seeds, longevity can be enhanced by drying and lowering storage temperature.

Activation of violaxanthin cycle in darkness is a common response to different abiotic stresses: a case study in Pelvetia canaliculata.

Background: In the violaxanthin (V) cycle, V is de-epoxidized to zeaxanthin (Z) when strong light or light combined with other stressors lead to an overexcitation of photosystems. However, plants can also suffer stress in darkness and recent reports have shown that dehydration triggers V-de-epoxidation in the absence of light. In this study, we used the highly stress-tolerant brown alga Pelvetia canaliculata as a model organism, due to its lack of lutein and its non-photochemical quenching independent of the transthylakoidal-ΔpH, to study the triggering of the V-cycle in darkness induced by abiotic stressors.

Ageing and irradiance enhance vitamin E content in green edible tissues from crop plants.

Background: Tocopherol (vitamin E) is an antioxidant essential in human nutrition. Several approaches have aimed to enhance tocopherol content in crops by the genetic modification of plants, a practice that generates some social concern. As tocopherol accumulates with leaf age in some wild plants and the antioxidant mechanisms respond with flexibility to stress conditions, it is hypothesised that tocopherol content can be increased in edible plants by the manipulation of harvesting time and growth conditions, in particular irradiance.

High irradiance induces photoprotective mechanisms and a positive effect on NH4+ stress in Pisum sativum L.

Photosynthesis provides plant metabolism with reduced carbon (C) but is also the main source of oxidative stress in plants. Likewise, high doses of NH(4)(+) as sole N source have been reported to be toxic for most plants, resulting in reduced plant growth and restricting C availability. The combination of high photosynthetic photon flux densities (PPFD) and NH(4)(+) nutrition may provide higher C availability but could also have a detrimental effect on the plants, therefore the objective of this study is to evaluate whether NH(4)(+) induces photo-oxidative stress that is exacerbated under high light conditions.

Differences in EDTA-assisted metal phytoextraction between metallicolous and non-metallicolous accessions of Rumex acetosa L.

Two common sorrel (Rumex acetosa) accessions, one from a Zn-Pb contaminated site (CS accession) and the other from an uncontaminated site (UCS accession), were hydroponically exposed to a mixture of heavy metals (Pb(2+) + Zn(2+) + Cd(2+)) with and without EDTA at an equimolar rate. The metallicolous CS accession showed a higher tolerance to metal treatment in the absence of the chelating agent, whereas the UCS accession was especially tolerant to EDTA treatment alone. Combination of metal and EDTA treatment resulted in a higher Pb accumulation in shoots of both accessions although plants hardly showed phytotoxic symptoms.

Lutein epoxide cycle, more than just a forest tale.

Two xanthophyll cycles have been described in higher plants: the ubiquitous violaxanthin (V) cycle and the taxonomically restricted lutein epoxide (Lx) cycle. Both involve the light induced de-epoxidation of an epoxidated xanthophyll (V or Lx) and the epoxidation back in the dark. Evolutionary trends and function of the Lx cycle are still not clear.

Alternative methods for sampling and preservation of photosynthetic pigments and tocopherols in plant material from remote locations.

Current methods for the study of pigments involve freezing in liquid nitrogen and storage at -80 degrees C or lyophilization until HPLC analysis. These requirements greatly restrict ecophysiological research in remote areas where such resources are hardly available. We aimed to overcome such limitations by developing several techniques not requiring freezing or lyophilization.

Dark induction of the photoprotective xanthophyll cycle in response to dehydration.

Some plants tolerate tissue dehydration. Dehydration conditions suppress photosynthesis, exacerbating photooxidative stress. In this study, fern samples were collected from the field, desiccated in darkness, and subsequently re-watered.

Photoprotective implications of leaf variegation in E. dens-canis L. and P. officinalis L.

Variegated leaves occur rarely in nature, but there are some species, primarily in the forest understory, that possess this characteristic. We recently studied two variegated plants: Erytronium dens-canis L., which is characterised by a pattern of red patches and Pulmonaria officinalis L.

Dynamics of violaxanthin and lutein epoxide xanthophyll cycles in Lauraceae tree species under field conditions.

Two xanthophyll cycles have been described in higher plants: the violaxanthin xanthophyll (V or VAZ) cycle, which is present in all species, and the taxonomically restricted lutein epoxide xanthophyll (Lx) cycle, which involves the light-induced de-epoxidation of Lx to lutein (L) and its epoxidation back to Lx in low light. Laboratory experiments indicate that the first reaction occurs quickly, but the second reaction is much slower. We investigated the Lx cycle under field conditions in several tree species of the Lauraceae family to determine its relationship with the ubiquitous V cycle.

Functional role of red (retro)-carotenoids as passive light filters in the leaves of Buxus sempervirens L.: increased protection of photosynthetic tissues?

Red (retro)-carotenoids accumulate in chloroplasts of Buxus sempervirens leaves during the process of winter leaf acclimation. As a result of their irregular presence, different leaf colour phenotypes can be found simultaneously in the same location. Five different colour phenotypes (green, brown, red, orange, and yellow), with a distinct pattern of pigment distribution and concentration, have been characterized.

Acclimation of antioxidant pools to the light environment in a natural forest canopy.

•  Leaf growth irradiance determines the pools of photoprotective molecules. We asked whether the potential for acclimation of antioxidant pool size to changes in the leaf light environment is affected by the position of the leaf within the canopy profile. •  The study was conducted in a mixed canopy formed by Tilia cordata at the lower level and Populus tremula at the upper level.