Reaction of street trees to adverse environmental conditions in the centre of Warsaw

The present study aimed atanalysing the trees growing along the four main streets of Warsaw - Marszałkowska, Świętokrzyska, Jana Pawła II and Solidarności Avenues - in order to evaluate the condition of each of them. The observations made in 1973 and in 2007 revealed that in this time the trees passed from 1631 to 1014, which stands for 40.3% of the original number. The biggest loss was noted for species: Sorbus aucuparia L. (94%), Acer pseudoplatanus L. (83%), Tilia cordata Mill. (65%) and Tilia ‘Euchlora’ (62%). None of the species, that were growing in 1973, could have been more tolerant to the specific environmental conditions in the vicinity of the road. The observations made in September had shown that the most frequent average value of the leaf damage index was above 3. The growing of this index showed that as vegetation period was passing by the condition of the trees was getting worse.The comparison of the leaf damage index carried out in September showed that in 2007 the health condition in 2007 was slightly better than in 1973

Effect of salt stress on prenol lipids in the leaves of Tilia ‘Euchlora’

Soil contamination caused by the NaCl used to de-ice slippery roads in winter is now recognized as one of the major causes of nutrient disorders and death in urban trees. It is believed that polyisoprenoids may have a specific role in the adaptation of plants to adverse conditions and habitats; it is further believed that in the cell, they may exhibit a protective effect in response to biotic and abiotic stress. The aim of this study was to evaluate the effect of salt stress on the content of prenol lipids in the leaves of Crimean linden (Tilia ‘Euchlora’). The Cl content in the slightly damaged (“healthy”) leaves averaged 0.96%, while that in the heavily damaged (“sick”) leaves averaged 2.02%. The leaves of control trees contained on average 0.57% Cl. The Na contents in the healthy and damaged leaves were 208 mg/kg and 1038 mg/kg, respectively, and the Na content in the control areas was 63 mg/kg. A mixture of polyprenols consisting of four compounds, prenol-9, prenol-10, prenol-11 and prenol-12, was identified in the leaves of Crimean linden. This mixture was dominated by prenol-10 (2.16–6.90 mg/g). The polyprenol content was highest in the leaves of “healthy” trees (approximately 13.31 mg/g), was lower in the case of “sick” trees (approximately 9.18 mg/g), and was the lowest in the control trees (mean 4.71 mg/g). No changes were observed in the composition of the mixture of polyprenols under these conditions. The results suggest that polyprenols may affect the accumulation of Cl in leaves. This phenomenon is evidenced by the high content of prenols in the leaves of trees considered “healthy” but growing under conditions of increased soil salinity and the lower content of prenols in the leaves of the “sick” and control trees. It is advisable to further investigate the role of prenol lipids in the leaves of trees subjected to salt stress. BACZEWSKA A., DMUCHOWSKI W., JÓŹWIAK A., GOZDOWSKI D., BRĄGOSZEWSKA P., DĄBROWSKI P., ŚWIEŻEWSKA E

Quantitative and qualitative characteristics of cell wall components and prenyl lipids in the leaves of Tilia x euchlora trees growing under salt stress

The study was focused on assessing the presence of arabinogalactan proteins (AGPs) and pectins within the cell walls as well as prenyl lipids, sodium and chlorine content in leaves of Tilia x euchlora trees. The leaves that were analyzed were collected from trees with and without signs of damage that were all growing in the same salt stress conditions. The reason for undertaking these investigations was the observations over many years that indicated that there are trees that present a healthy appearance and trees that have visible symptoms of decay in the same habitat. Leaf samples were collected from trees growing in the median strip between roadways that have been intensively salted during the winter season for many years. The sodium content was determined using atomic spectrophotometry, chloride using potentiometric titration and poly-isoprenoids using HPLC/UV. AGPs and pectins were determined using immunohistochemistry methods. The immunohistochemical analysis showed that rhamnogalacturonans I (RG-I) and homogalacturonans were differentially distributed in leaves from healthy trees in contrast to leaves from injured trees. In the case of AGPs, the most visible difference was the presence of the JIM16 epitope. Chemical analyses of sodium and chloride showed that in the leaves from injured trees, the level of these ions was higher than in the leaves from healthy trees. Based on chromatographic analysis, four polyisoprenoid alcohols were identified in the leaves of T. x euchlora. The levels of these lipids were higher in the leaves from healthy trees. The results suggest that the differences that were detected in the apoplast and symplasm may be part of the defensive strategy of T. x euchlora trees to salt stress, which rely on changes in the chemical composition of the cell wall with respect to the pectic and AGP epitopes and an increased synthesis of prenyl lipids

Effect of salt stress in urban conditions on two Acer species with different sensitivity

Background. The benefits of trees in urban areas include the following: an increase in ecosystem health, an increase in human health, the mitigation of the effects of heat and drought at microclimate level, the storage and sequestration of carbon, and a reduction in air pollution and noise. These ecosystem services can be provided only by trees that are in good health. The main cause of salt stress in urban environments is the use of deicing salts on the streets in winter. Salt stress is a complex process that includes changes in plants on the physiological, histological, cellular and molecular levels, leading to limitations in nutrient uptake, disrupting the ionic balance of trees and resulting in the death of roadside trees. In response to salinity, trees have developed a variety of defence mechanisms that allow them to minimize the effects of stress and maintain homeostasis. Methodology. The reactions of two species Acer species: A. platanoides and A. campestre, which have different sensitivities to the unfavourable conditions of the urban environments (mainly salt stress), were investigated. The research included two experiments: a field experiment with city trees and a controlled pot experiment with young trees treated with increasing doses of salt. In both experiments, the following were performed: an assessment of the health condition of the trees and the content of macroelements as well as the Cl and Na in leaves and a qualitative and quantitative analysis of polyprenols. Results. A. campestre had a more specific strategy than A. platanoides for dealing with Na and Cl, which resulted in undamaged leaves. Under the same conditions, A. platanoides leaves contained more Cl and Na and were severely damaged. The disruption of the ion balance due to salt stress was lower in A. campestre than in A. platanoides. Compared with A. platanoides, A. campestre synthesized more polyprenols in the field experiment. This ability was acquired during the process of acclimation, because it occurred only in the mature trees in the field experiment and not in the young trees in the pot experiment. Conclusions. The use of two experimental methods (i.e., the field and pot experiments) allowed for a more complete assessment of tree strategies to mitigate salt stress. A. campestre displayed a more specific strategy than A. platanoides. This strategy was based on several elements. A. campestre limited Cl and Na transport to the leaves, which resulted in a lack of damage to those organs. Under the same conditions, A. platanoides individuals contained more Cl and Na in their leaves and were seriously damaged. A. campestre synthesized larger amounts of polyprenols, which probably have the ability to mitigate salt stress. This ability was acquired during the process of acclimation, because it occurred only in the mature trees in the field experiment and was not observed in the young trees in the pot experiment

The Use of Mosses in Biomonitoring of Air Pollution in the Terrestrial Environment: A Review

Environmental biomonitoring is an excellent supplement to instrumental methods of environmental quality assessment. The use of biological methods has many advantages (relatively low cost, independence from the source of energy in the field etc.). The limitation in the use of bioindication methods is the inability to compare the results with legal environmental pollution standards. Mosses are commonly used in air pollution monitoring. Mosses exhibit most of the characteristics attributed to effective bioindicators. The advantage of mosses over other bioindicators comes from the fact that the result depends only on-air pollution due to the lack of practical contact with the soil. Mosses are used in air pollution biomonitoring in two basic methods: naturally growing or transplanted to the researched area. They are most often used to assess air pollution by metals and other elements, but also by various organic compounds. A prerequisite for successful application of these methods is strict adherence to a recognised methodology and standardisation of all activities, such as random selection of measurement points. The article presents a critical analysis of the advantages and disadvantages of biomonitoring of air pollutants, along with a final recommendation for their use, provided that appropriate methodological rigor is maintained. An important advantage of mosses in biomonitoring is their relatively practical ease of application and interpretation of results, resulting in their widespread use

The Ectomycorrhizal Community of Crimean Linden Trees in Warsaw, Poland

Urban trees provide many ecosystem services essential to city dwellers well-being. Ectomycorrhizal (ECM) fungi are symbionts for trees and may also contribute to urban tree health and thus maintenance of the ecosystem services. However, no studies so far have analysed the composition of the ECM community colonising Crimean linden. In this study we investigated ECM associations of Crimean linden trees in the urban environment, comparing street trees with those growing in a park. Moreover, we studied the ECM community of healthy versus unhealthy linden trees growing along a street. The health status of each tree was assessed using tree health indicators. The smallest degree ECM colonisation was observed in unhealthy street trees (40.5%). Cenococcum geophilum was found to be the most abundant ECM fungal species of the Crimean linden growing in the park (23.9%). Our results suggest that the linden trees growing in the park and those growing along the street but without disease symptoms did not differ in their ECM richness. However, the unhealthy street trees showed less ECM diversity and abundance. Moreover, strong negative correlations between the concentrations of Na and Cl in the soil and ECM colonisation were found. This study describes, for the first time, the ECM fungal community on Tilia “Euchlora” trees grown in Europe. We report novel findings on the ECM associations of Crimean linden trees in an urban ecosystem. Further research should focus on the role of native mycorrhizal fungal communities in nutrient acquisition by urban trees in the presence of salt stress

Evaluation of the impact of reducing national emissions of SO2 and metals in Poland on background pollution using a bioindication method.

Changes in environmental pollution by S, Cd, Cu, Pb and Zn in 2006-2014 were evaluated using a bioindication method. This method was based on measurements of pollutants in Scots pine (Pinus sylvestris L.) needles. The measurements were performed in the Chojnowskie Forests, a region recognized as a background area for central Poland. The changes in the contents of sulfur (S) and metals in needles were not comparable with the changes in the global emissions of the pollutants in Poland. On average, the pollution level in the study area decreased by 9.9% for S, 61.4% for Pb, 22.5% for Cd, 11.7% for Zn and 10.4% for Cu. During the same period, global emissions in Poland decreased by 38.1% for S, 8.0% for Pb, 63.2% for Cd, 11.7% for Zn and 14.0% for Cu. Therefore, the differences in the changes in emissions and the needle contents of each element should be examined separately which was not a goal of this study. However, the discrepancy between these results did not prevent the use of bioindication methods. Evaluation of pollutant contents in plants reflected their incorporation in biological processes rather than air or soil pollution levels

The importance of prenol lipids in mitigating salt stress in the leaves of Tilia × euchlora trees

De-icing salt has been used on streets and pavements in most northern countries since the 1960s. Salt stress limits all vital functions of trees. Tilia × euchlora is planted in many cities given its unique decorative qualities. The aim of this study was to determine the tree strategy to mitigate salt stress due to the synthesis of polyprenols in leaves. Many years of observations have demonstrated that trees of the same species growing in the same street conditions may have extremely different health statuses. The study consisted of two experiments: a field experiment with urban street trees growing in saline soils and a controlled pot experiment with young trees exposed to increasing doses of salt. The differences between the young trees from the pot experiment and older trees from the field experiment were expressed in their ability to synthesize polyprenols. In urban conditions, the tree leaves with less damage contained signifcantly more polyprenols than did those with more damage. The salt stress mitigation strategy may be related to the ability to synthesize polyprenols. This ability can be acquired through adaptation by older trees. The mechanism involves limiting the transport of Cl− and Na+ to leaves. In the pot experiment, the young trees did not exhibit this ability

Strategies of urban trees for mitigating salt stress: a case study of eight plant species

Street trees are exposed to relatively high stress levels, and the average lifespan of street trees is shortened compared to those of trees living under controlled natural conditions. Soil salinity adversely affects trees at all stages of growth and development. This study attempts to determine how the urban environment, with particular emphasis on salt stress, affects tree species with different levels of salinity sensitivity. The aim of this study was to identify the strategies of eight tree species for mitigating salt stress based on the determination of the chemical composition of the macroelements in the leaves, the ionic imbalance, and the ability of the trees to synthesize and accumulate polyprenols in the leaves. The obtained results suggest that individual species implemented different strategies in response to salt stress. The low sensitivity species: Q. rubra, R. pseudoacacia, G. triacanthos and A. campestre. blocked the uptake of Cl and Na to the leaves. The mediumsensitivity species: P. x hispanica blocked the uptake of Cl and Na and G. biloba maintained very high contents of Cl and Na in its leaves without leaf damage and synthesized large amounts of polyprenols. G. triacanthos and A. campestre synthesized large amounts of polyprenols. The high-sensitivity species (T. x euchlora and A. platanoides) exhibited very high contents of Cl and Na in their leaves, which were significantly damaged and had a pronounced ionic imbalance. These effects were not compensated for by the increased synthesis of polyprenols. In conclusion, the accumulation of polyprenols in leaf tissue may be one of the strategies that increase the resistance of plants to salt stress. Plants have many other methods of mitigating salt stress