Photosynthetic light acclimation of leaves can result from (i) changes in mass-based leaf nitrogen concentration, Nm, (ii) changes in leaf mass:area ratio, Ma, and (iii) partitioning of total leaf nitrogen among different pools of the photosynthetic machinery. We studied variations in Nm and Ma within the crowns of two peach (Prunus persica L. Batsch) trees grown in an orchard in Portugal, and one peach tree grown in an orchard in France. Each crown was digitized and a 3-D radiation transfer model was used to quantify the intra-crown variations in time-integrated leaf irradiance, . Nitrogen concentration, leaf mass:area ratio, chlorophyll concentration, and photosynthetic capacity were also measured on leaves sampled on five additional peach trees in the orchard in Portugal. The data were used to compute the coefficients of leaf nitrogen partitioning among carboxylation, bioenergetics, and light harvesting pools. Leaf mass:area ratio and area-based leaf nitrogen concentration, Na, were nonlinearly related to , and photosynthetic capacity was linearly related to Na. Photosynthetic light acclimation resulted mainly from changes in Ma and leaf nitrogen partitioning, and to a lesser extent from changes in Nm. This behavior contrasts with photosynthetic light acclimation observed in other tree species like walnut (Juglans regia L.) in which acclimation results primarily from changes in Ma.

Fusarium circinatum , the causal agent of pine pitch canker (PPC), is an emergent and still understudied risk that threatens Pinus forests worldwide, with potential production and sustainability losses. In order to explore the response of pine species with distinct levels of susceptibility to PPC, we investigated changes in physiology, hormones, specific gene transcripts, and primary metabolism occurring in symptomatic Pinus pinea , Pinus pinaster , and Pinus radiata upon inoculation with F. circinatum . Pinus radiata and P. pinaster exhibiting high and intermediate susceptibility to PPC, respectively, suffered changes in plant water status and photosynthetic impairment. This was associated with sink metabolism induction, a general accumulation of amino acids and overexpression of pathogenesis-related genes. On the other hand, P. pinea exhibited the greatest resistance to PPC and stomatal opening, transpiration increase, and glycerol accumulation were observed in inoculated plants. A stronger induction of pyruvate decarboxylase transcripts and differential hormones regulation were also found for inoculated P. pinea in comparison with the susceptible Pinus species studied. The specific physiological changes reported herein are the first steps to understand the complex Pinus–Fusarium interaction and create tools for the selection of resistant genotypes thus contributing to disease mitigation.

The goal of this work was to correlate oxidative stress caused by reactive oxygen species (ROS) and DNA damage with classic semen parameters in spermatozoa and seminal plasma of fertile and subfertile stallions. Oxidation was measured in both lipids and proteins, using the thiobarbituric acid reactive species (TBARS) assay and the DNPH carbonyl groups assay, respectively. Sperm DNA damage was monitored using the TUNEL assay. These parameters were monitored in samples obtained during the breeding and the non-breeding seasons. In general, fertile stallions showed better classical semen parameters, and those parameters improved from the non-breeding to the breeding season, although an increase in sperm production was accompanied by a decrease in the semen quality from subfertile stallions in the breeding season. In terms of oxidation levels we found that there were clear differences whether lipids or proteins were considered. In the breeding season there seemed to be a tendency towards normalizing lipid oxidation in spermatozoa and seminal plasma, and protein oxidation in the seminal plasma, of both fertile and subfertile animals. Thus, differences monitored in the non-breeding season were no longer visible. Interestingly, a higher level of protein oxidation was found in the sperm of fertile animals in the breeding season. Considering that there were positive correlations between sperm protein oxidation and sperm motility and vitality, these results suggests that the oxidation of semen proteins may be important for sperm function. On the other hand, lipid oxidation in the seminal plasma seemed to be a general indicator for sperm damage. In the non-breeding season positive correlations between lipid and protein oxidation levels in both sperm and seminal plasma and several defects in sperm function were found, but only for subfertile animals, thus suggesting that lipid and protein oxidation may aid in the identification of subfertile stallions during the non-breeding season. Levels of ROS production never seemed to result in compromised sperm DNA integrity, indicating that measurements were within physiological levels and/or that there is an efficient antioxidant activity in stallion sperm cells.

While effects of (a)biotic stress events in the phyllosphere have been studied intensively, possible influences of stress on the arbuscular mycorrhizal hyphosphere has scarcely been investigated. We hypothesised that stress challenge in the phyllosphere could alter primary metabolite profiles of the hyphosphere - the mycelial network connecting plants. Donor plants, connected to receiver plants by mycelial networks, were aphid-challenged during 84 h. Primary metabolite profiles in the hyphosphere were investigated. Gene-expression of plant defence gene PR1 was measured in one of the receiver plants during the challenge. Hexose levels in the hyphosphere increased when donor plants were aphid-challenged. This change in metabolic profile was influenced by leaf sampling from receiver plant. PR1 expression increased in donor plants 48 h after challenge, and consequently 60 h after, in receiver plants. We conclude that aphid infestation of donor plants modified primary carbon metabolism in the hyphosphere. Plant defence response in receiver plants, occurred 12 h after detection of response in the aphid-challenged donor plants. While this work is the first to reveal primary metabolic profiles of the AM hyphosphere, more work is needed to elucidate the possible role of transient changes of hexose metabolism in stress response and signalling processes in the hyphosphere of connected plants.

Quercetin has been the subject of numerous studies on its genetic toxicity and carcinogenicity. Despite its well-proven genetic damaging activity for various genetic end-points (reverse mutations, induction of SOS functions, induction of sister chromatid exchanges, chromosomal aberrations and micronuclei), the mechanisms of genetic damage by quercetin remain, by and large, unknown. The present study aims to further extend the observations on the possible active oxygen species mediated DNA-damaging activity of quercetin and the role of cytochrome P450-dependent metabolism on the genotoxicity of quercetin. The results reported in this work show that quercetin can produce the OH. radical, as assessed by deoxyribose degradation in the presence of Fe3+/EDTA (ethylenediaminetetraacetic acid), and that it induces strand breakage in isolated plasmidic DNA (pUC18). The data support the hypothesis that the production of OH. is mediated by H2O2. The results with genetically engineered V79 cells expressing rat cytochromes 1A1, 1A2 and 2B1 failed to demonstrate metabolism of quercetin, as indicated by the fact that neither an enhancement nor a decrease in the genotoxicity of quercetin was observed. Results obtained on the pH dependence of the induction of chromosomal aberrations by quercetin in V79 cells show that, as the pH value of the medium is increased to 8.0, there is a significant increase in the number of aberrant cells, as expected if oxygen radicals are responsible for the formation of chromosomal aberrations.

Pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease, a serious threat to global forest populations of conifers, especially Pinus spp. A time-course study of the essential oils (EOs) of 2-year-old Pinus halepensis, Pinus pinaster, Pinus pinea and Pinus sylvestris following inoculation with the PWN was performed. The constitutive and nematode inoculation induced EOs components were analyzed at both the wounding or inoculation areas and at the whole plant level. The enantiomeric ratio of optically active main EOs components was also evaluated. External symptoms of infection were observed only in P. pinaster and P. sylvestris 21 and 15 days after inoculation, respectively. The EO composition analysis of uninoculated and unwounded plants revealed the occurrence of chemotypes for P. pinaster, P. halepensis and P. sylvestris, whereas P. pinea showed a homogenous EO composition. When whole plants were evaluated for EO and monoterpene hydrocarbon enantiomeric chemical composition, no relevant qualitative and quantitative differences were found. Instead, EO analysis of inoculated and uninoculated wounded areas revealed an increase of sesquiterpenes and diterpenic compounds, especially in P. pinea and P. halepensis, comparatively to healthy whole plants EOs.

Appropriate experimental design and sample preparation are key steps in metabolomics experiments, highly influencing the biological interpretation of the results. The sample preparation workflow for plant metabolomics studies includes several steps before metabolite extraction and analysis. These include the optimization of laboratory procedures, which should be optimized for different plants and tissues. This is particularly the case for trees, whose tissues are complex matrices to work with due to the presence of several interferents, such as oleoresins, cellulose. A good experimental design, tree tissue harvest conditions, and sample preparation are crucial to ensure consistency and reproducibility of the metadata among datasets. In this review, we discuss the main challenges when setting up a forest tree metabolomics experiment for mass spectrometry (MS)-based analysis covering all technical aspects from the biological question formulation and experimental design to sample processing and metabolite extraction and data acquisition. We also highlight the importance of forest tree metadata standardization in metabolomics studies.

This study aimed to assess two end-points of DNA damage, namely chromosomal aberrations and micronuclei in peripheral lymphocytes, and their possible relationship with oxidative stress (which may be related to DNA damage and repair) in thyroid cancer patients receiving therapeutic doses of (131)I. Nineteen patients receiving 2590 MBq (70 mCi) were studied. Chromosomal aberrations were scored using standard cytogenetic methods and micronuclei scored in cytokinesis-blocked lymphocytes. Oxidative stress was assessed by determining thiobarbituric acid-reactive substances in blood, total plasma antioxidant status and serum uric acid levels. All parameters were assessed before treatment and 1 and 6 months after (131)I administration. The frequency of micronucleated cells per 1000 binucleated cells scored (mean +/- SEM) increased significantly from 5.21 +/- 0.80 to 9.68 +/- 1.22 1 month after treatment (P < 0.01) and to 8.42 +/- 1.28 6 months after treatment (P < 0.05). The frequency of cells with chromosomal aberrations, excluding gaps, per 100 cells, increased significantly from 1.68 +/- 0.41 to 3.47 +/- 0. 55 1 month after treatment (P < 0.01) and to 4.05 +/- 0.46 6 months after treatment (P < 0.01). Oxidative stress parameters showed slight modifications over the time period studied, but the differences were not significant except for a decrease in thiobarbituric acid-reactive products 6 months after therapy (P < 0. 05) and in serum uric acid concentration 1 and 6 months after therapy (P < 0.01). This report demonstrates slight but significant and persistent DNA damage in (131)I-treated patients as assessed by cytogenetic assays. There was no clear correlation between the cytogenetic findings and oxidative stress parameters studied.