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Concept: Tilia


Harmonia axyridis has been introduced as a biological control agent in Europe and the USA. Since its introduction, it has established and spread, and it is now regarded as an invasive alien species. It has been suggested that intraguild predation is especially important for the invasion success of H. axyridis. The aim of this study was to compare the intraguild predation behaviour of three ladybird species (Coccinella septempunctata, Adalia bipunctata, and H. axyridis). Predation behaviour was investigated in semi-field experiments on small lime trees (Tilia platyphyllos). Two fourth-instar larvae placed on a tree rarely made contact during 3-hour observations. When placed together on a single leaf in 23%-43% of the observations at least one contact was made. Of those contacts 0%-27% resulted in an attack. Harmonia axyridis attacked mostly heterospecifics, while A. bipunctata and C. septempunctata attacked heterospecifics as often as conspecifics. In comparison with A. bipunctata and C. septempunctata, H. axyridis was the most successful intraguild predator as it won 86% and 44% of heterospecific battles against A. bipunctata and C. septempunctata respectively, whilst A. bipunctata won none of the heterospecific battles and C. septempunctata won only the heterospecific battles against A. bipunctata. Coccinella septempunctata dropped from a leaf earlier and more often than the other two species but was in some cases able to return to the tree, especially under cloudy conditions. The frequency with which a species dropped did not depend on the species the larva was paired with. The results of these semi-field experiments confirm that H. axyridis is a strong intraguild predator as a consequence of its aggressiveness and good defence against predation from heterospecific species. The fact that H. axyridis is such a strong intraguild predator helps to explain its successful establishment as invasive alien species in Europe and the USA.

Concepts: Biological pest control, Invasive species, Introduced species, Coccinellidae, Harmonia axyridis, Tilia, Coccinella septempunctata, Biological pest control agents


Linden flower is a wildly used plant material among patients in the treatment of common cold symptoms and mucosa inflammations. However, the structure and bioactivity of flavan-3-ol derivatives present in infusions from flowers of Tilia cordata have not been studied so far. The aim of current study was to isolate and identify main procyanidins present in the flowers of small-leaved lime and to evaluate their influence on the inflammatory response of human neutrophils ex vivo. The chemical structure of isolated compounds was established by 1D and 2D NMR experiments. The bioactivity of obtained compounds was tested in human neutrophils model. Cytotoxicity and influence of compounds on apoptosis was established by flow cytometry. The levels of produced cytokines were established ELISA after stimulation with lipopolysaccharide (LPS). The inhibition of the production of reactive oxygen species was checked by luminol dependent chemiluminescence method after N-formylmethionyl-leucyl-phenylalanine (f-MLP) induction. The phytochemical work resulted in the isolation of 10 compounds. Compounds were identified as oligomeric procyanidins and their precursor epicatechin. The potential anti-inflammatory activity of compounds was evaluated in the concentration range 5-20 μM. All compounds were able to decrease the production of ROS from f-MLP-stimulated neutrophils. Most of compounds were able to inhibit the LPS-induced release of IL-8. Some trimeric and tetrameric derivatives were also able to decrease the production of MIP-1β. Obtained results partially support the traditional usage of infusion from lime flowers in the treatment of symptoms of inflammation and irritation of mucosa in common cold, pharyngitis and tonsillitis.

Concepts: Inflammation, Inflammations, Reactive oxygen species, Tilia cordata, Tilia, Tilia americana, Tilia platyphyllos, Tilia × europaea


Many species of plants produce leaves with distinct teeth around their margins. The presence and nature of these teeth can often help botanists to identify species. Moreover, it has long been known that more species native to colder regions have teeth than species native to warmer regions. It has therefore been suggested that fossilized remains of leaves can be used as a proxy for ancient climate reconstruction. Similar studies on living plants can help our understanding of the relationships. The required analysis of leaves typically involves considerable manual effort, which in practice limits the number of leaves that are analyzed, potentially reducing the power of the results. In this work, we describe a novel algorithm to automate the marginal tooth analysis of leaves found in digital images. We demonstrate our methods on a large set of images of whole herbarium specimens collected from Tilia trees (also known as lime, linden or basswood). We chose the genus Tilia as its constituent species have toothed leaves of varied size and shape. In a previous study we extracted c.1600 leaves automatically from a set of c.1100 images. Our new algorithm locates teeth on the margins of such leaves and extracts features such as each tooth’s area, perimeter and internal angles, as well as counting them. We evaluate an implementation of our algorithm’s performance against a manually analyzed subset of the images. We found that the algorithm achieves an accuracy of 85% for counting teeth and 75% for estimating tooth area. We also demonstrate that the automatically extracted features are sufficient to identify different species of Tilia using a simple linear discriminant analysis, and that the features relating to teeth are the most useful.

Concepts: Photosynthesis, Species, Plant, Fern, Tilia, Tilia americana, Tiliaceae, Unter den Linden


A new type of promising chitosan beads with advanced properties were obtained under microwave radiation according to Green Chemistry principles. Biomaterials were prepared using chitosan as raw material and glutamic acid/1,5-pentanodiol mixture as crosslinking agents. Additionally beads were modified with Tilia platyphyllos extract to enhance their antioxidant properties. Beads were investigated over their chemical structure by FT-IR analysis. Also their morphology has been investigated by SEM method. Additionally swelling capacity of the obtained hydrogels was determined. Lack of cytotoxicity has been confirmed by MTT assay. Proliferation studies were carried out on L929 mouse fibroblasts. Advanced properties of the obtained beads were investigated by studying pH sensitivity and antioxidant properties by DPPH method. Also susceptibility to degradation and biodegradation by Sturm Test method was evaluated. Results shows that proposed chitosan beads and their eco-friendly synthesis method can be applied in cell therapy and tissue engineering.

Concepts: Cell, Chemistry, Electromagnetic spectrum, Cytotoxicity, Chemical compound, MTT assay, Tilia, Tilia platyphyllos


Climate, e.g., air temperature and precipitation, differs strongly between urban and peripheral areas, which causes diverse life conditions for trees. In order to compare tree growth, we sampled in total 252 small-leaved lime trees (Tilia cordata Mill) in the city of Berlin along a gradient from the city center to the surroundings. By means of increment cores, we are able to trace back their growth for the last 50 to 100 years. A general growth trend can be shown by comparing recent basal area growth with estimates from extrapolating a growth function that had been fitted with growth data from earlier years. Estimating a linear model, we show that air temperature and precipitation significantly influence tree growth within the last 20 years. Under consideration of housing density, the results reveal that higher air temperature and less precipitation led to higher growth rates in high-dense areas, but not in low-dense areas. In addition, our data reveal a significantly higher variance of the ring width index in areas with medium housing density compared to low housing density, but no temporal trend. Transferring the results to forest stands, climate change is expected to lead to higher tree growth rates.

Concepts: Density, Temperature, Ideal gas, Tilia cordata, Tilia, Tilia americana, Tilia platyphyllos, Tilia × europaea


The present work aims to provide a contribution to the overall investigation of European unifloral honeys with regard to authentication according to botanical and geographical origins. The mineral content of 206 monofloral honey samples of five botanical origins from six different regions in Serbia was investigated by inductively coupled plasma optical emission spectrometry. Chemometric techniques were applied for the classification and differentiation of acacia, sunflower, and linden honey according to botanical origin, as well as acacia honey samples according to regional origin. The highest influence on the differentiation of acacia honey samples was the presence of siderophile and chalcophile elements, whereas sunflower and linden honeys were determined by the presence of lithophile elements, indicating their origin from soil. However, due to the different bioaccumulation properties of plants, the presence of elements is not necessarily directly correlated to their presence in soil, which is confirmed by the results of the authentication of geographical origin of acacia honey.

Concepts: Time, Spectroscopy, Chemical element, Sugar, Honey, Acacia, Tilia, Monofloral honey


Urbanized areas are struggling with the problem of air pollution and when the number of people living in cities increasing, the situation is likely to deteriorate. One of the most harmful pollutants is particulate matter (PM). Increased levels of PM in the atmosphere are likely to have a negative impact on human health. Phytoremediation technology could be a solution. It involves plants acting as bio-filters by accumulating particles on, and in the leaves, which removes the particles from the atmosphere.This study looks at the accumulation of PM including heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs), on the foliage of small-leaved lime (Tilia cordata Mill.) in five Polish cities. Significant differences in PM amounts were found between trees growing in the different cities which related to the amount of PM in the atmosphere. Significant differences were found between cities for the amounts of the different particulate size fractions, and the HMs and PAHs in leaves. Strong winds reduced the amount of PM on leaves, especially the smallest fractions, but no connection with precipitation was found. The results suggest that T. cordata is improving the air quality in cities and can be used as an effective bioindicator for PM air pollution.

Concepts: Photosynthesis, Polycyclic aromatic hydrocarbon, Atmosphere, Smog, Air pollution, Naphthalene, Tilia cordata, Tilia


Carbon reserves are important for maintaining tree function during and after stress. Increasing tree mortality driven by drought globally has renewed the interest in how plants regulate allocation of recently fixed C to reserve formation. Three year-old seedlings of two species (Tilia platyphyllos, Pinus sylvestris) were exposed to two intensities of experimental drought during ~ 10 weeks and (13) C pulse labelling was subsequently applied with rewetting. Tracking the (13) C-label across different organs and C compounds (soluble sugars, starch, myo-inositol, lipids and cellulose), together with the monitoring of gas exchange and C mass balances over time, allowed for the identification of variations in C allocation priorities and tree C balances that are associated to drought effects and subsequent drought release. The results demonstrate that soluble sugars accumulated in P. sylvestris under drought conditions independently of growth trends; thus NSC formation cannot be simply considered a passive overflow process in this species. Once drought ceased, C allocation to storage was still prioritized at the expense of growth, which suggested the presence of ‘drought memory effects’, possibly to ensure future growth and survival. On the contrary, NSC and growth dynamics in T. platyphyllos were consistent with a passive (overflow) view of NSC formation.

Concepts: Glucose, Plant, Regulation, Cellulose, Seed, Pine, Tilia, Tilia platyphyllos


Naturally-occurring phytochemicals have received pivotal attention in the last few years, due to the increasing evidence of biological activities. Thus, in the present study, the antioxidant, anti-inflammatory and antitumor potentials of hydroethanolic extracts rich in phenolic compounds obtained from Equisetum giganteum L. and Tilia platyphyllos Scop. were assessed and directly correlated with their content of phenolic compounds, by using HPLC-DAD-ESI/MS analysis. T. platyphyllos showed the higher bioactive potential, evaluated in terms of antioxidant (radical scavenging effects - 105 μg mL(-1), reducing power - 123 μg mL(-1), β-carotene bleaching inhibition - 167 μg mL(-1), and lipid peroxidation inhibition - 56 μg mL(-1)), anti-inflammatory (225 μg mL(-1) inhibited 50% of nitric oxide production) and antitumor (breast - 224 μg mL(-1); lung - 247 μg mL(-1); cervical - 195 μg mL(-1) and hepatocellular - 173 μg mL(-1) carcinoma cells) activity, without having cytotoxic effects (>400 μg mL(-1)). These biological properties were positively correlated with its content and composition of phenolic compounds. Flavonoid contents were markedly higher than the content of phenolic acids, in both samples, being respectively 50.4 mg g(-1) and 11.65 mg g(-1) for T. platyphyllos, and 21.7 mg g(-1) and 4.98 mg g(-1) for E. giganteum. Moreover, while in E. giganteum extract, kaempferol-O-glucoside-O-rutinoside was the most abundant flavonoid, in T. platyphyllos extract protocatechuic acid and (-)-epicatechin were the most abundant phenolic acid and flavonoid, respectively. In relation to their content of phenolic acids, protocatechuic and caffeic acids existed in higher abundance in T. platyphyllos and E. giganteum hydroethanolic extracts, respectively. However, it would be interesting to evaluate the in vivo efficacy of both plant extracts to unveil the involved modes of action and to establish effective therapeutic doses.

Concepts: Oxygen, Antioxidant, Nitric oxide, Resveratrol, Phenols, Phenol, Tilia, Tilia platyphyllos


The effects of urban conditions on tree growth have been investigated in an increasing number of studies over the last decades, emphasizing the harsh environment of cities. Urban trees often grow in highly paved, compacted sites with consequently less soil moisture, higher soil temperatures, and greater vapor pressure deficits. However, there is still a knowledge gap regarding the impact of harsh paved environments on urban tree growth during drought years on the growth patterns of urban trees. The present study investigated the structure and growth of the common urban tree species small-leaved lime (Tilia cordata) at a highly paved public square (CPS) compared with a contrasting more open, greener square (OGS). Continuously, measured high precision dendrometer data along with meteorological data of the extreme dry and warm summer 2015 as well as dendrochronological data of the sampled trees were investigated to analyze tree growth during a drought year. The results highlight different tree dimensions and growth patterns of the trees at both sites, influenced by tree age and distinct site conditions. While the trees at OGS grew up to 2.5 mm from July until mid of August, the trees at CPS had only 0.4-mm diameter increment. After the initial expansion at CPS, tree diameter contracted again during summer to the point of shrinkage (up to 0.8 mm) at the end of our investigation. Further drought year analysis confirmed the patterns of significant stem growth reductions in the consecutive two years following the drought. A correlation analysis revealed that transpiration, air temperature, and vapor pressure deficit were negatively correlated with the daily diameter growth, whereas precipitation had a strong positive effect. Due to high transpiration rates associated with anisohydric water use behavior, T. cordata was able to provide evaporative cooling even during drought. However, this anisohydric behavior resulted in substantial growth decline afterwards especially at paved sites like CPS. Our results suggest selection of tree species, such as those with isohydric water use behavior, which may achieve a better balance between growth, transpiration, and hence evaporative cooling.

Concepts: Water, Precipitation, Soil, Tree, Tilia cordata, Tilia, Tilia americana, Tilia platyphyllos