Abiotic and biotic stresses affect plant physiology and growth. The development of metabolomics, along with other -omics technologies, allowed in depth analysis of the reactive processes ...characterizing plant stress as the result of the alteration of metabolites and gene expressions. Here, we organize and interpret data from 151 studies to provide an overview about metabolomic shift after exposure to either abiotic or biotic stresses including drought, salinity, heat, heavy metal, cold, pathogens and insects. Data showed that amino acids, organic acids, sugars, and sugar alcohols quantities are influenced by stresses. Proline for example, increased in almost every stress condition, while other molecules increased or decreased depending specifically on plant tissue, plant species and type of applied stress. We concluded that although it is difficult to predict precisely what a stress will cause, some general metabolic trends can be described and improve our understanding of plant response to biotic and abiotic stresses.
Aims
Data on the decomposition of fine roots are scarce for the Mediterranean basin. This work aims to compare chemical traits, decomposition rate, and temperature sensitivity (
Q
10) for root and ...leaf litter of 43 Mediterranean species.
Methods
We carried out a two-years litterbag decomposition experiment using 43 fine roots litter and leaf litter types incubated in laboratory conditions at three different temperatures, i.e. 4 °C, 14 °C, and 24 °C. Litter was characterized for carbon (C), nitrogen (N), lignin and cellulose concentration, C/N, and lignin/N ratios.
Results
Fine root litter had lower N content but higher lignin concentration, lignin/N, and C/N ratios compared to leaf litter. The decay rate of fine root litter was slower than leaf litter. For both tissues, the decay rate was negatively associated with lignin concentration, lignin/N, and C/N ratios but positively with N concentration.
Q
10 was higher for fine root than leaf litter, with a positive correlation with lignin while negative with N concentration.
Conclusions
Our findings demonstrate a higher
Q
10 accompanied by a slower decomposition rate of fine root litter compared to leaf litter in Mediterranean ecosystems. These results must be considered in modeling organic C at the ecosystem scale.
Accurate application of agrochemicals is an important way to achieve efficient use of chemicals and to combine limited pollution with effective control of weeds, pests, and diseases. In this context, ...we investigate the potential application of a new delivery system based on ink-jet technology. First, we describe the structure and functionality of ink-jet technology for agrochemical delivery. We then evaluate the compatibility of ink-jet technology with a range of pesticides (four herbicides, eight fungicides, and eight insecticides) and beneficial microbes, including fungi and bacteria. Finally, we investigated the feasibility of using ink-jet technology in a microgreens production system. The ink-jet technology was compatible with herbicides, fungicides, insecticides, and beneficial microbes that remained functional after passing through the system. In addition, ink-jet technology demonstrated higher area performance compared to standard nozzles under laboratory conditions. Finally, the application of ink-jet technology to microgreens, which are characterized by small plants, was successful and opened the possibility of full automation of the pesticide application system. The ink-jet system proved to be compatible with the main classes of agrochemicals and showed significant potential for application in protected cropping systems.
Understanding processes controlling forest dynamics has become particularly important in the context of ongoing climate change, which is altering the ecological fitness and resilience of species ...worldwide. However, whether forest communities would be threatened by projected macroclimate change or unaffected due to the controlling effect of local site conditions is still a matter for debate. After all, forest canopy buffer climate extremes and promote microclimatic conditions, which matters for functional plant response, and act as refugia for understory species in a changing climate. Yet precisely how microclimatic conditions change in response to climate warming will depend on the extent to which vegetation structure and local topography shape air and soil temperature. In this study, we posited that forest microclimatic buffering is sensitive to local topographic conditions and canopy cover, and using meteorological stations equipped with data-loggers we measured this effect during 1 year across a climate gradient (considering aspect as a surrogate of local topography) in a Mediterranean beech treeline growing in contrasting aspects in southern Italy. During the growing season, the below-canopy near-ground temperatures were, on average, 2.4 and 1.0 °C cooler than open-field temperatures for south and north-west aspects, respectively. Overall, the temperature offset became more negative (that is, lower under-canopy temperatures at the treeline) as the open-field temperature increased, and more positive (that is, higher under-canopy temperatures at the treeline) as the open-field temperature decreased. The buffering effect was particularly evident for the treeline on the south-facing slope, where cooling of near-ground temperature was as high as 8.6 °C for the maximum temperature (in August the offset peaked at 10 °C) and as high as 2.5 °C for the average temperature. In addition, compared to the south-facing slope, the northern site exhibited less decoupling from free-air environment conditions and low variability in microclimate trends that closely track the free-air biophysical environment. Although such a decoupling effect cannot wholly isolate forest climatic conditions from macroclimate regional variability in the south-facing treeline, it has the potential to partly offset the regional macroclimatic warming experienced in the forest understory due to anthropogenic climate change.
Plant–soil negative feedback (NF) is recognized as an important factor affecting plant communities. The objectives of this work were to assess the effects of litter phytotoxicity and autotoxicity on ...root proliferation, and to test the hypothesis that DNA is a driver of litter autotoxicity and plant–soil NF. The inhibitory effect of decomposed litter was studied in different bioassays. Litter biochemical changes were evaluated with nuclear magnetic resonance (NMR) spectroscopy. DNA accumulation in litter and soil was measured and DNA toxicity was assessed in laboratory experiments. Undecomposed litter caused nonspecific inhibition of root growth, while autotoxicity was produced by aged litter. The addition of activated carbon (AC) removed phytotoxicity, but was ineffective against autotoxicity. Phytotoxicity was related to known labile allelopathic compounds. Restricted¹³C NMR signals related to nucleic acids were the only ones negatively correlated with root growth on conspecific substrates. DNA accumulation was observed in both litter decomposition and soil history experiments. Extracted total DNA showed evident species‐specific toxicity. Results indicate a general occurrence of litter autotoxicity related to the exposure to fragmented self‐DNA. The evidence also suggests the involvement of accumulated extracellular DNA in plant–soil NF. Further studies are needed to further investigate this unexpected function of extracellular DNA at the ecosystem level and related cellular and molecular mechanisms.
Litter decomposition provides a continuous flow of organic carbon and nutrients that affects plant development and the structure of decomposer communities. Aim of this study was to distinguish the ...feeding preferences of microbes and plants in relation to litter chemistry. We characterized 36 litter types by
C-CPMAS NMR spectroscopy and tested these materials on 6 bacteria, 6 fungi, and 14 target plants. Undecomposed litter acted as a carbon source for most of the saprophytic microbes, although with a large variability across litter types, severely inhibiting root growth. An opposite response was found for aged litter that largely inhibited microbial growth, but had neutral or stimulatory effects on root proliferation.
C-CPMAS NMR revealed that restricted resonance intervals within the alkyl C, methoxyl C, O-alkyl C and di-O-alkyl C spectral regions are crucial for understanding litter effects. Root growth, in contrast to microbes, was negatively affected by labile C sources but positively associated with signals related to plant tissue lignification. Our study showed that plant litter has specific and contrasting effects on bacteria, fungi and higher plants, highlighting that, in order to understand the effects of plant detritus on ecosystem structure and functionality, different microbial food web components should be simultaneously investigated.
Ailanthus altissima
is an aggressive invasive tree worldwide, but the ecological factors that lead to the spread of this species in Mediterranean ecosystems are still unclear. Here we aim to identify ...such factors, focusing on the interaction of human activity with climatic conditions. We determined the occurrence and abundance of
Ailanthus
in 240 sites and studied their relationship with 20 variables representing climatic, geographic, and topographic factors, as well as land use, in the region of Campania (southern Italy). Overall, we found that temperature and rainfall in Campania are suitable for
Ailanthus
, with the only major constraint being the temperature at an altitude exceeding 900 m a.s.l.. We found that
Ailanthus
is unable to spread where the mean annual temperature is lower than 11.1 °C. By contrast, precipitation variables showed poor correlation with
Ailanthus
distribution, suggesting that rainfall in the selected study sites is suitable to sustain the growth of this tree. About land use variables, roads were the primary landscape feature along which this species spread and invaded new areas. Roads probably combine high propagule pressure and favorable growing conditions in terms of available resources i.e., light, water, and mineral nutrients, that allow
Ailanthus
to establish and spread along roadside edges in different ecosystems. In conclusion, we found that climate and human-associated variables are correlated with the current occurrence of
Ailanthus
, with the temperature being more influential at high elevation sites and road distance playing a prominent role in low elevation areas.
Biochar is nowadays largely used as a soil amendment and is commercialized worldwide. However, in temperate agro-ecosystems the beneficial effect of biochar on crop productivity is limited, with ...several studies reporting negative crop responses. In this work, we studied the effect of 10 biochar and 9 not pyrogenic organic amendments (NPOA), using pure and in all possible combinations on lettuce growth (
). Organic materials were characterized by
C-CPMAS NMR spectroscopy and elemental analysis (pH, EC, C, N, C/N and H/C ratios). Pure biochars and NPOAs have variable effects, ranging from inhibition to strong stimulation on lettuce growth. For NPOAs, major inhibitory effects were found with N poor materials characterized by high C/N and H/C ratio. Among pure biochars, instead, those having a low H/C ratio seem to be the best for promoting plant growth. When biochars and organic amendments were mixed, non-additive interactions, either synergistic or antagonistic, were prevalent. However, the mixture effect on plant growth was mainly dependent on the chemical quality of NPOAs, while biochar chemistry played a secondary role. Synergisms were prevalent when N rich and lignin poor materials were mixed with biochar. On the contrary, antagonistic interactions occurred when leaf litter or woody materials were mixed with biochar. Further research is needed to identify the mechanisms behind the observed non-additive effects and to develop biochar-organic amendment combinations that maximize plant productivity in different agricultural systems.
Here, we quantified the dieback of
Silene acaulis
subsp.
bryoides
along a 500 m elevational transect from 1900 to 2400 m a.s.l. in the Sibillini Group (Apennines). We also investigated the role of ...the 2022 summer heat wave that affected the Apennines as a putative cause. The intensity of the dieback was not uniformly distributed across the elevational gradient, but was widespread at 1900 and 2000 m a.s.l. and decreased with increasing elevation. Specifically, 40.7% and 38.4% of plants were affected by dieback at 1900 and 2000 m a.s.l., respectively, but less than 1% at elevations above 2300 m a.s.l. Regarding climate, the maximum air temperature in 2022 was 3.7, 4.5, and 3.4 °C above the respective long-term average in May, June, and July. A similar trend was observed for the minimum temperature. The monthly maximum (21.5 °C) and minimum (14.6 °C) temperatures in July were the highest ever recorded since the monitoring station was commissioned in 2005. In terms of daily maximum temperatures, three consecutive days with temperatures above 25 °C were recorded in July 2022, an upper limit that has only been reached on four days in the last 17 years. Regarding precipitation, 180 mm of precipitation fell during the May–August growing season compared to the long-term average of 255 mm, a decrease of 30%. More importantly, only 15.2 mm of rain fell in July 2022, compared to a long-term average of 54.3 mm. The sudden dieback of
Silene
highlights the vulnerability of high elevation vegetation to climate change. Moreover, the loss of
Silene
cushions is alarming for the survival of the species, which is long lived but very slow growing.
Biodeterioration is defined as the alteration of a given substrate due to a combination of physical and chemical factors produced by living organisms when attached to such materials. This phenomenon ...attracts scientific research attention due to its risk in causing destruction to outdoor cultural rock heritage sites. In this review, an update on the state-of-art regarding the biodeterioration phenomenon is represented in order to highlight the type of colonizing vegetation and possible mechanisms behind the corresponding deterioration. For this reason, 62 articles with a focus on lichens, mosses, and higher plants were investigated by evaluating the role of construction materials and different plant species related to the hazard index. The results showed that trees and shrubs are the most harmful plant life forms, for example,
,
, and
, while regarding building materials, those characterized by high porosity, such as andesite and argillaceous limestone, are more vulnerable to plant colonization. Further studies are needed to examine in detail the relationship between colonizing organisms, intrinsic elements of the substrate, and external factors, as well as the refinement of measures to prevent and control colonization by plants.
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