Aims
In Mediterranean ecosystems fire and drought are two natural disturbances that affect plant traits and generate a highly heterogeneous landscape. The objective of this research was to analyze ...leaf chemistry, one important driver of carbon and nutrients cycles, and decomposition of
Phillyrea angustifolia
L. in a landscape affected by recurrent fire disturbance.
Methods
We investigated leaf litter collected in a low-maquis at sites burned by a wildfire 10 years before the current study, at sites burned by an experimental fire 1 year before and at sites located at the edge low-maquis/gaps.
Results
The three litters differed in chemical composition, mass loss and dynamics of lignin/AUR (Acid-Unhydrolizable-Residue), nitrogen and manganese. During the early decomposition phase lignin/AUR increased in litters from sites burned 1 year before and from sites located at the edge low-maquis/gaps and decreased in litter from sites burned 10 years before. Nitrogen and manganese were immobilized in litter during the early and the middle phase of decomposition.
13
C NMR spectroscopy revealed that all the litters were rich in Alkyl-C, the fraction including waxes and cutin that are effective barriers to water loss from the leaves. Litter from sites burned 1 year before had the highest hydrophobicity and aromaticity indexes and the highest alkyl ratio, and decomposed at the lowest rate.
Conclusions
Differences of leaf chemical composition within the same plant species across an uneven landscape affect decomposition. The traditional approach and
13
C NMR spectroscopy complementarily explain decomposition pattern and give a comprehensive view of the individual drivers of litter decomposition.
Purposes
The aim of this paper was to characterize elements dynamics, including resorption before leaf shedding and accumulation/release during decomposition, of two functionally different tree ...species, the N-fixing, broadleaf, deciduous black locust (
Robinia pseudoacacia
L.), and the Mediterranean black pine (
Pinus nigra
Arn.), planted on recent unconsolidated volcanic deposits.
Methods
In two paired, 40 years old stands, we investigated the stoichiometry of thirteen elements in green leaves, newly shed leaf litter, stable litter residue and soil.
Results
Black locust leaves were richer in N, P, K, Mg and Mn; black pine needles were richer in Na, Fe, Zn, Cr, and Pb. Resorption efficiency was Pb > Zn > Fe ~ N ~ Mn ~ Mg > Cd ~ K > P in black locust, and Pb ~ Cu > Zn ~ Na > Mn > K ~ Cr in black pine. Compared to black pine, black locust newly shed litter was richer in K, Na, Mn, Cu, and Ni. During decomposition, black locust leaf litter released N, K, Mg, Na, Mn, Zn, Cu and Cd, and accumulated Fe, Ni, Cr and Pb, whilst black pine needles released N, Zn and Cd, and accumulated all the other elements. Compared to black locust black pine had a stable needle litter residue richer in all elements but N, whilst the mineral soil was poorer in all elements but Pb.
Conclusions
The two functionally different tree species have distinct element dynamics from leaf to far decomposed litter. Element sequestration in the stable residue of black pine litter, likely prevents their release in the mineral soil that is thus poorer in nutrients and minor elements compared to the soil of black locust.
L. is a well-known fruit worldwide, and its highest production occurs in tropical and subtropical regions. The pulp contains vitamins A, C, and E, B complex vitamins, such as pantothenic acid and ...folate, and minerals, such as magnesium and potassium, as well as food fibers. Phenolic compounds, such as benzyl isothiocyanate, glucosinolates, tocopherols (α and δ), β-cryptoxanthin, β-carotene and carotenoids, are found in the seeds. The oil extracted from the seed principally presents oleic fatty acid followed by palmitic, linoleic and stearic acids, whereas the leaves have high contents of food fibers and polyphenolic compounds, flavonoids, saponins, pro-anthocyanins, tocopherol, and benzyl isothiocyanate. Studies demonstrated that the nutrients present in its composition have beneficial effects on the cardiovascular system, protecting it against cardiovascular illnesses and preventing harm caused by free radicals. It has also been reported that it aids in the treatment of diabetes mellitus and in the reduction of cholesterol levels. Thus, both the pulp and the other parts of the plant (leaves and seeds) present antioxidant, anti-hypertensive, hypoglycemic, and hypolipidemic actions, which, in turn, can contribute to the prevention and treatment of obesity and associated metabolic disorders.
Episodic angioedema with eosinophilia (EAE) is a rare condition characterized by recurrent attacks of angioedema and urticaria accompanied by a marked elevation of peripheral eosinophil count. We ...report the case of a young female patient diagnosed with EAE associated with urticarial vasculitis. A 40-year-old female patient was admitted to our institution due to recurrent episodes of cheek and eyelid angioedema in the previous year. Episodes of facial angioedema lasted for two months with spontaneous remission afterwards. In addition, she presented pruritic and painful skin eruptions of erythematous circles, which persisted for longer than 24 h, that were palpable, somewhat purplish, and more pronounced on the face, arms, and trunk. Laboratory investigation showed a sustained elevation of white cell counts with marked eosinophilia. Serum IgM, IgE, and IgA were normal; IgG was slightly elevated. C1-esterase inhibitor and tryptase test were normal. Reverse transcriptase-polymerase chain reaction was performed for detection of FIP1L1-PDGFRA and BCR-ABL rearrangements. None of these alterations were found. Skin biopsies were suggestive of urticarial vasculitis. The patient was submitted to esophagogastroduodenoscopy, which showed mild chronic gastritis, with no eosinophilic infiltration. Cardiac dimensions and function were normal. Abdominal ultrasound and total body CT-scan failed to show lymphadenopathy, organomegaly, and tumors. We report the first case of association between episodic angioedema with eosinophilia and urticarial vasculitis. It is possible that both conditions share a physiopathological mechanism, suggesting that it is not just a chance association.
We synthesized available data for decomposition of pine (Pinus) needle litter in pine forests to determine the litter chemical characteristics and climate factors that explained variation in the ...limit value, i.e. the level of accumulated mass loss at which the decomposition process either continues at a very low rate or possibly stops. Our data base included 56 separate studies on decomposition of pine needle litter, spanning Scots pine, lodgepole pine, Aleppo pine, stone pine and white pine, mainly incubated at the site of collection. Studies had 5 to 19 samplings, on average 10, and the decomposition was followed to a mass loss ranging from 47 to 83%, on average 67%. The periods from 3.0 to 5.4 years, on average 3.9 years, were of sufficient duration to allow estimates of limit values of decomposition. We used a linear mixed model with regression effects to relate limit values to potential explanatory variables, namely the sites' long-term mean annual temperature (MAT) and mean annual precipitation (MAP) and to substrate-chemistry factors. Regarding the latter, we explored two models; one that included initial concentrations of water solubles, lignin, N, P, K, Ca, Mg, and Mn and one that included only lignin, N, Ca, and Mn to focus on those nutrients known to influence lignin degradation. Using backward elimination significant explanatory variables were determined. For litter decomposed in its site of origin we found the limit value to depend mainly on the initial concentration of Mn, with higher Mn concentrations resulting in higher accumulated mass loss. Thus, litter with higher Mn reached a higher limit value and left a smaller stable fraction. This is likely due to the fact that Mn is an essential component of ligninolytic enzymes important for degrading litter in the later stages of decomposition. Manganese has received little attention in decomposition studies to date. Given its significance in this synthesis, the role of Mn in influencing variation in the late stages of decomposition among ecosystems and among litters of other genera besides Pinus deserves further attention.
We have studied the muon neutrino and antineutrino quasi-elastic (QEL) scattering reactions (
ν
μ
n
→
μ
−
p
and
) using a set of experimental data collected by the NOMAD Collaboration. We have ...performed measurements of the cross-section of these processes on a nuclear target (mainly carbon) normalizing it to the total
ν
μ
(
) charged-current cross section. The results for the flux-averaged QEL cross sections in the (anti)neutrino energy interval 3–100 GeV are
and
for neutrino and antineutrino, respectively. The axial mass parameter
M
A
was extracted from the measured quasi-elastic neutrino cross section. The corresponding result is
M
A
=1.05±0.02(stat)±0.06(syst) GeV. It is consistent with the axial mass values recalculated from the antineutrino cross section and extracted from the pure
Q
2
shape analysis of the high purity sample of
ν
μ
quasi-elastic 2-track events, but has smaller systematic error and should be quoted as the main result of this work. Our measured
M
A
is found to be in good agreement with the world average value obtained in previous deuterium filled bubble chamber experiments. The NOMAD measurement of
M
A
is lower than those recently published by K2K and MiniBooNE Collaborations. However, within the large errors quoted by these experiments on
M
A
, these results are compatible with the more precise NOMAD value.
To analyse the characteristics and predictors of death in hospitalized patients with coronavirus disease 2019 (COVID-19) in Spain.
A retrospective observational study was performed of the first ...consecutive patients hospitalized with COVID-19 confirmed by real-time PCR assay in 127 Spanish centres until 17 March 2020. The follow-up censoring date was 17 April 2020. We collected demographic, clinical, laboratory, treatment and complications data. The primary endpoint was all-cause mortality. Univariable and multivariable Cox regression analyses were performed to identify factors associated with death.
Of the 4035 patients, male subjects accounted for 2433 (61.0%) of 3987, the median age was 70 years and 2539 (73.8%) of 3439 had one or more comorbidity. The most common symptoms were a history of fever, cough, malaise and dyspnoea. During hospitalization, 1255 (31.5%) of 3979 patients developed acute respiratory distress syndrome, 736 (18.5%) of 3988 were admitted to intensive care units and 619 (15.5%) of 3992 underwent mechanical ventilation. Virus- or host-targeted medications included lopinavir/ritonavir (2820/4005, 70.4%), hydroxychloroquine (2618/3995, 65.5%), interferon beta (1153/3950, 29.2%), corticosteroids (1109/3965, 28.0%) and tocilizumab (373/3951, 9.4%). Overall, 1131 (28%) of 4035 patients died. Mortality increased with age (85.6% occurring in older than 65 years). Seventeen factors were independently associated with an increased hazard of death, the strongest among them including advanced age, liver cirrhosis, low age-adjusted oxygen saturation, higher concentrations of C-reactive protein and lower estimated glomerular filtration rate.
Our findings provide comprehensive information about characteristics and complications of severe COVID-19, and may help clinicians identify patients at a higher risk of death.
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Non-photochemical quenching (NPQ) is a complex and still unclear mechanism essential for higher plants. The intensive research on this subject has highlighted three main components of NPQ: ...energy-dependent process (qE); state transitions to balance the excitation of PSII and PSI (qT); and photoinhibitory processes (qI). Recently, these components have been resolved as quantum yields according to the energy partitioning approach that takes into account the rate constants of every process involved in the quenching mechanisms of excited chlorophylls. In this study a fully extended quantum yield approach and the introduction of novel equations to assess the yields of each NPQ component are presented. Furthermore, a complete analysis of the yield of NPQ in
Beta vulgaris exposed to different irradiances has been carried out. In agreement with experimental results here it is shown that the previous approach may amplify the yield of qE component and flatten the quantitative results of fluorescence analysis. Moreover, the significance of taking into account the physiological variability of NPQ for a correct assessment of energy partitioning is demonstrated.
The present study investigates the impact of fire (low and high severity) on soil fungal abundance and microbial efficiency in C assimilation and mineralisation in a Mediterranean maquis area of ...Southern Italy over 2 years after fire. In burned and control soils total and active fungal mycelium, microbial biomass C, percentage of microbial biomass C present as fungal C, metabolic quotient (qCO₂) and coefficient of endogenous mineralisation (CEM) were assayed together with several chemical properties of soil (i.e. pH and contents of organic C, total and mineral N, available K, Mg, Mn and water). Fire significantly decreased the fungal mycelium, whereas it stimulated microbial growth probably through the enhancement of bacterial growth because of the increase in organic C and nutrient contents in burned plots. This shift in microbial community composition might explain the observed reduction in soil microbial efficiency of C assimilation (high qCO₂) and the increase in C mineralisation rate (CEM) in the first 84 days after fire. Therefore, fire might increase CO₂ input to the atmosphere not only during combustion phase but also in the post-fire period.
The scenarios for the long-term habitation of space platforms and planetary stations involve plants as fundamental part of Bioregenerative Life Support Systems (BLSS) to support the crew needs. ...Several constraints may limit plant growth in space: among them ionizing radiation is recognized to severely affect plant cell at morphological, physiological and biochemical level. In this work, plants of Phaseolus vulgaris L. were subjected to four different doses of X-rays (0.3, 10, 50 and 100Gy) in order to assess the effects of ionizing radiation on this species and to analyze possible mechanisms carried out to overcome the radiation injuries. The effects of X-rays on plant growth were assessed by measuring stem elongation, number of internodes and leaf dry weight. The integrity of photosynthetic apparatus was evaluated by photosynthetic pigment composition and ribulose 1,5-bisphosphate carboxylase (Rubisco) activity, whereas changes in total antioxidant pool and glutathione S transferase activity (GST) were utilized as markers of oxidative stress. The distribution of phenolic compounds in leaf tissues as natural shielding against radiation was also determined.
Irradiation of plants at 0.3 and 10Gy did not determine differences in all considered parameters as compared to control. On the contrary, at 50 and 100Gy a reduction of plant growth and a decrease in photosynthetic pigment content, as well as an increase in phenolic compounds and a decrease in total antioxidant content and GST activity were found. Only a slight reduction of Rubisco activity in leaves irradiated at 50 and 100Gy was found. The overall results indicate P. vulgaris as a species with a good potential to face ionizing radiation and suggest its suitability for utilization in BLSSs.
•Bean plants have been irradiated with four doses of X-rays: 0.3, 10, 50 and 100Gy.•High doses limit plant growth and increase the content of leaf phenolic compounds.•At high doses chlorophylls, total antioxidants and S transferase activity decrease.•Bean radioresistance is related to the induction of antioxidative-defense mechanisms.
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