Search Results (26)

Stilbenes are plant secondary metabolites with remarkable antidiabetic, anti-inflammatory, antimicrobial, antioxidant, antitumor, and neuroprotective properties. As these compounds are valuable constituents in healthcare products and promising drug candidates, exploring new sources of stilbenes is essential for therapeutic advancement. The present study reports the isolation of two stilbene glycosides, resveratroloside and pinostilbenoside, from Pinus cembra L. bark. Their antioxidant activity and cytotoxic effects against HeLa cells were evaluated in comparison to the raw bark extract. The structures of resveratroloside and pinostilbenoside were confirmed by nuclear magnetic resonance (NMR) and mass spectrometry (MS) data analyses. Antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and reducing power assays. Cell viability, apoptosis, cell proliferation, and cell cycle assays were used to evaluate the cytotoxic potential against HeLa cells. Resveratroloside and pinostilbenoside exhibited lower activity as free radical scavengers and reducing agents. However, they showed greater efficacy in reducing viability and suppressing proliferation in human cervical carcinoma HeLa cells. Given the promising findings of our study, the therapeutic potential of resveratroloside and pinostilbenoside should be further investigated. Full article

Swiss stone pine (Pinus cembra L.) may represent a vital species for afforestation at the upper altitudinal limits of forests due to its adaptability to challenging environmental conditions. In this study, we aimed to analyze the variability in ring width (radial growth, RW, earlywood, EW, latewood, LW, and latewood proportion, LWP) and the influence of different sites on the climatic resilience of twelve European provenances of Swiss stone pine to identify the best-adapted provenances. Five provenances from the Alps and seven from the Carpathians were tested across two 27-year-old field trials conducted in the Eastern and Southern Carpathians. Moderate genetic differentiation among the provenances was noted, which could ensure the success of breeding programs. Based on ring width and latewood proportion, we successfully selected the 25% best-performing provenances and recommend them for use in the provenance regions where have performed. The significant influence of the testing site and the different outcomes of the provenances necessitate extreme attention during the transfer of forest reproductive materials. Additionally, the breeding strategies applied in the two trials differed, consisting in individual selection in the Cugir trial and provenance selection in the Cârlibaba trial. The low resistance of all provenances shown in both trials, particularly in the Cugir trial, is worrying in the context of global warming. Full article

Swiss stone pine (Pinus cembra) is a feasible solution for increasing the resistance of future mixed spruce–pine stands to windfall at the upper altitudinal limit of Romanian forests. This study aims to analyze the adaptability of ten full-sib families in two different environmental conditions and their evolution in time for predicting forward selection. At a seedling age of 33, evaluations were carried out for survival rate (Sr), growth (diameter at breast height—Dbh, and trees’ height), and branch traits, as well as for stem straightness. The high level of genetic variability, inheritance rate, and trait–trait correlations, registered in both trials, ensure the success of the breeding program. The Swiss stone pine shows a very good adaptation on high-sloping lands from the upper altitudinal limit of Romania’s forests, with the cross-pollinated (CP) families registering a 28.5% better survival in the Rodna trial (34° slope) compared to the Păltiniș experiment (7° slope). The consanguineous families registered only an 11% Sr in Păltiniș, while in the Rodna trial, the Sr was four times higher (in both trials, consanguineous trees were dominated). The juvenile–adult correlations of growth traits were significant, indicating that early selection could be efficient. The forward selection of the best 10% of CP families for Dbh could be applied, ensuring a 9% to 15% genetic gain. Full article

The heartwood of the Swiss Stone Pine, Pinus cembra L., has been scarcely investigated for secondary metabolites for a long period of time. Considering age and relative simplicity of heartwood investigations dating back to the 1940s to 1960s, we conducted the first investigation of P. cembra heartwood by HPLC, using UHPLC-DAD-ESI-MSⁿ and HPLC-DAD techniques in combination with isolation and NMR spectroscopy, with focus on stilbenes, bibenzyls and flavonoids. Analytical problems in the HPLC analysis of Pinus stilbenes and flavonoids on reversed stationary phases were also challenged, by comparing HPLC on pentafluorophenyl (PFP) and C18 stationary phases. Seven flavonoids (1, 2, 3, 7, 8, 11, 12), four stilbenes (4, 6, 10, 13), two bibenzyls (5, 9), three fatty acids (14, 16, 17) and one diterpenic acid (15) were detected in an ethanolic extract of Pinus cembra heartwood. HPLC comparison of reversed stationary phases in HPLC showed that the antifungal, antibacterial and chemosensitizing dihydropinosylvin monomethyl ether (9) and pinosylvin monomethyl ether (10) can be separated on PFP, but not on C18 material, when eluting with a screening gradient of 20–100% acetonitrile. Flavonoid separation showed additional benefits of combining analyses on different stationary phases, as flavonoids 7 and 8 could only be separated on one of two C18 stationary phases. Earlier phytochemical results for heartwood investigations were shown to be mostly correct, yet expandable. Substances 5 to 12 were found in alignment with these references, proving remarkable phytochemical analyses at the time. Evidence for the described presence of pinobanksin could not be found. Substances 1 to 4 and 13 have to our knowledge not yet been described for P. cembra. Full article

Pinus cembra L., also known as Swiss pine, is one of the lesser studied coniferous species, despite literature pointing out its great potential to be used for medical purposes due to its high contents in active phytochemicals. The aim of this study is to phytochemically assess rhytidome and periderm extracts obtained from Swiss pine from various locations and altitudes, so as to be able to deduce the best locations for harvesting samples with the highest biological activity. After the plant was analyzed histo-anatomically, hydroalcoholic extracts were obtained using ultrasounds, a rotary evaporator, and dry freezing. After determining the total polyphenolic content (TPC) in each sample, they were tested for antioxidant and enzymatic activity, while taking note of the influence of the varying altitudes and different harvesting regions on the intensity of each activity. The results from the TPC analysis show that rhytidome samples collected from the highest altitude (2429 m) displayed the highest content of polyphenols, with a general tendency for the amount of polyphenolic content to be directly correlated to altitude, this finding being further supported by the antioxidant activity also growing directly proportionally with the altitude. Enzymatic inhibition activity was found to be moderate for α-glucosidase and low for α-amylase. Following our findings, we can safely say that Pinus cembra L. extracts can be a great source of compounds with antioxidant activity; however, further studies are warranted to best determine the true potential of this species. Full article

Information about climate–growth relationships is crucial for predicting the potential climatic impact on tree species, especially those growing on the edges of their distribution range, for instance, in high-elevation forests. This study aimed to determine changes in the relationships between tree-ring widths and daily climatic data in high-elevation forests in the Western Carpathians over time. Climate–growth relationships were calculated to obtain the TRWI (tree-ring-width index) chronology (based on 104 trees) and day-wise aggregated data for temperature (mean, minimum, and maximum) and sums of precipitation. The radial growth of stone pine was mostly determined by the mean temperature in the period between mid-June (21st) and the beginning of July (4th) for the critical 14-day window width (r = 0.44). The negative influence of precipitation on the radial growth occurred in summer (r = −0.35) and overlapped with the period of the positive influence of temperature. Dendroclimatic studies based on daily data may define the exact periods (expressed in calendar days) that influence the radial growth of trees much better than the commonly used monthly means. This is particularly important in analysing the growth of trees at high elevations, where the climatic factor strongly limits radial growth. Full article

The browsing of wild ungulates can have profound effects on the structure and composition of forests. In the Swiss National Park, the density of wild ungulates, including red deer (Cervus elaphus), ibex (Capra ibex), and chamois (Rupicapra rupicapra), is exceptionally high due to strict protection and the absence of large predators. We examined count data of larch (Larix decidua), cembra pine (Pinus cembra), spruce (Picea abies), upright mountain pine (Pinus mugo subsp. uncinata), and mountain ash (Sorbus aucuparia) of four sampling years between 1991 and 2021, and modelled how topographic and location factors affected the probability of browsing on saplings of larch, cembra pine, and spruce. Despite the high density of wild ungulates, the number of saplings and young trees has increased over the past 30 years. The probability of browsing on saplings was highest for larch at a height of 10–40 cm and increased with increasing elevation. In our study area, open grasslands are mainly located above the tree line, which might explain the positive correlation between elevation and the probability of browsing. Further, the probability of browsing was related to exposition and slope, diversity of tree species, and disturbance by humans. It appears that in the investigated part of the Swiss National Park, the potential of the forest to regenerate has increased despite the high densities of wild ungulates. Full article

The chemical content of essential oils (EO) obtained from the leaves of four Pinaceae (Abies alba, Picea abies, Pinus cembra and Pinus mugo) was investigated by SPME-GC-MS technique. The vapor phase was characterized by the monoterpenes with values higher than 95.0%. Among them, α-pinene (24.7–48.5%), limonene (17.2–33.1%) and β-myrcene (9.2–27.8%) were the most abundant. The monoterpenic fraction prevailed over the sesquiterpenic one (≥74.7%) in the EO liquid phase. Limonene was the major compound in A. alba (30.4%), P. abies (20.3%) and P. mugo (78.5%), while α-pinene in P. cembra (36.2%). Regarding the phytotoxic properties, EOs were studied at different doses (2–100 μL) and concentrations (2–20/100 μL/mL). All EOs were found to be significantly active (p-value ˂ 0.05) against the two recipient species in a dose-dependent way. In pre-emergence tests, germination of Lolium multiflorum and Sinapis alba was reduced by up to 62–66% and 65–82%, respectively, as well as their growth by up to 60–74% and 65–67%, due to the effects of compounds in both the vapor and liquid phases. In post-emergence conditions, at the highest concentration, the phytotoxicity of EOs caused heavy symptoms and, in the case of S. alba, A. alba EO completely destroyed (100%) the treated seedlings. Full article

Using a scanning electron microscope, the micromorphologies of needle primordia and the young needles of seven pine species (Pinus cembra, P. mugo, P. nigra, P. rigida, P. sylvestris, P. strobus, and P. uncinata) were analyzed at phenological stages B2 and B3 (according to Debazac). In B2, needle tips were rounded or pointed, depending on the species. In P. cembra and P. strobus, teeth were noted on the tips. Teeth were also visible on the margins in P. mugo, P. cembra, and P. strobus. Stomata became visible in the late B2 phase (P. sylvestris, P. mugo, and P. nigra) near the needle tips and were arranged in rows. In the B3 phase, needle tips were pointed. Only in P. strobus was the needle tip slightly rounded. The teeth on the margin in all the species were pointed. In P. strobus, their size and density along the margin decreased basipetally. In B3 for all the species, numerous stomata were visible. In P. sylvestris, P. cembra, and P. strobus, Florin rings were also observed. These observations could be useful in pine systematics but also in palaeobotanical or physiological studies. To the best of our knowledge, this is the first study on the micromorphology of very young needles in representatives of the genus Pinus. Full article

Alpine treeline ecosystems are generally expected to advance with increasing temperatures and after land-use abandonment. Multiple interacting factors modify this trend. Understanding the long-term processes underlying treeline advance is essential to predict future changes in structure and function of mountain ecosystems. In a valley in the Central Swiss Alps, we re-assessed a 40-year-old survey of all treeline trees (>0.5 m height) and disentangled climate, topographical, biotic, and disturbance (land use and avalanche risk) factors that have led to treeline advance with a combination of ground-based mapping, decision tree, and dendroecological analyses. Between the first ground survey in 1972/73 and the resurvey in 2012, treeline advanced on average by 10 meters per decade with a maximum local advance of 42 meters per decade. Larch consistently advanced more on south-facing slopes, while pine advance was greater on north-facing slopes. Newly established spruce mostly represented infilling below the previous treeline. The forefront of treeline advance above 2330 m a.s.l. occurred mainly on favorable microsites without competing dwarf shrub vegetation. At slightly lower elevations, treeline advanced mainly on sites that were used for agriculture at the beginning of the 20th century. This study indicates that although treeline advances under the effect of climate warming, a combination of additional ecological factors controls this advance at regional and local scales. Full article

pH of xylem sap (pHx) was determined in three trees (Malus domestica (apple tree), Picea abies and Pinus cembra) in response to seasonal changes. Conifer trees from lowland (600 m) were compared to trees growing at the alpine timberline (1950 m a.s.l.). Xylem sap was extracted with a Scholander pressure bomb and pHx was measured with a pH microsensor. In all species, pHx changed markedly with season. In spring, pHx was acidic; during winter, the pHx was more alkaline. In apple trees, the pHx did not show a significant correlation with temperature but was rather affected by developmental stage. During flushing in spring, xylem sap acidification took place concomitant to the developmental stage “tight cluster”, when foliar development enables a significant transpiration and a consequent movement of water in the xylem. The xylem sap of the two studied conifers showed a significantly larger seasonal alkalinisation (+2.1) than found in apple trees (+1.2) and was significantly more pronounced at the timberline. Xylem sap acidification took place before bud break. pHx had a significant negative correlation with soil temperatures and corresponded to already reported pHx of angiosperms. Overall, pHx appears to be a sensitive stress marker and indicator of activity status in tree xylem. Full article

Green alder (Alnus alnobetula) is currently the most expanding shrub species in the Alps. Because dense thickets impair tree establishment, understanding how climate affects shrub growth is essential for predictions of treeline dynamics. We evaluated ring width data from >50 A. alnobetula stems sampled at treeline on Mt. Patscherkofel (Central European Alps, Austria) to identify main climatic drivers and influence of climate warming on radial stem growth (RG). We also compared RG of A. alnobetula with RG of the co-occurring treeline conifer Swiss stone pine (Pinus cembra). We addressed our questions through calculation of response functions and evaluation of climate in years showing exceptional growth deviations. Response function analyses and evaluation of growth trends during 1991–2020 revealed that RG of A. alnobetula is significantly and directly related to summer temperatures. Precipitation in January also showed a direct relationship to RG, indicating effects of frost drought on RG. Surprisingly, nitrogen fixing A. alnobetula showed strikingly lower RG compared to P. cembra, and the latter also responded more strongly to the increase in summer temperature in the course of climate warming. We explain these findings by different carbon allocation strategies, i.e., preference of “vertical” stem growth in late successional P. cembra vs. favoring “horizontal” spread in the pioneer shrub A. alnobetula. Full article

Age-related trends are present in tree-ring widths (TRW), but their presence in tree rings isotope is debated. It is unclear how cambial age influences the relationships between TRW and isotopes. Tree-ring isotopes of alpine larch and cembran-pine trees showed only trends in the juvenile period (>100 years), which might mask the inter-relations between tree-ring proxies during cambial age. This work tries to unmask the age-trend influences by examining the correlations in TRW—stable isotopes with and without age-trend correction. The non-detrended and linear-detrended values of TRW, of δD and δ¹⁸O showed significant correlations for ages up to 100 years, but not afterward. However, the correlation values, after spline or first-difference time-series detrending, were not age-related. Thus, detrending methods affect the correlations in the juvenile phase and may affect climate-related interpretations. The correlations between TRW and δ¹³C were not age-related, while those among the isotopes were significant throughout the ages. The correlation between δ¹³C and δD was the exception, as it became significant only after age > 100 years, suggesting a different use of reserves in the juvenile phase. In conclusion, the relationships among the tree-ring parameters are stable in all the different detrend scenarios after the juvenile phase, and they can be used together in multi-proxy paleoclimatic studies. The data of the juvenile phase can be used after spline-detrending or first-difference time-series calculation, depending on the purpose of the analysis to remove age-related trends. The work also provides clues on the possible causes of juvenile age trends. Full article

The high ambient ozone concentrations cause impairing effects on vegetation leading to plant injuries. The potential ozone uptake to vegetation through open stomata can be quantified using stomatal conductance measurements under the local environmental conditions. This study compares the ozone stomatal conductance to vegetation obtained with a modified Jarvis formula adopted from the Vegetation Manual of United Nations Economic Commission for Europe, and experimental field measurements’ data. The stomatal conductance was measured by a portable photosynthesis and gas exchange analyzer system LiCOR6400. The measurements were performed in the submontane environment of the High Tatra Mountains in Slovakia on Swiss pine (Pinus cembra), as a native species of the local flora. According to previous studies, Swiss pine is considered as an ozone-sensitive species. The modified Jarvis model for the ozone stomatal conductance is compared with the field measurements. The suitable parameterization of the modified Jarvis model for Swiss pine is obtained. The parameterization of stomatal conductance for Swiss pine in the local environment would help understand its specificity and similarity to other conifer species. In the case of using parameterization for a boreal coniferous from the Vegetation Manual of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops, validation of the model with the measurements without temperature adjustment of the conifer chamber achieved a coefficient of determination of $R^2=0.75$. This result is not in contradiction with the previous researches. With the optimal set of parameters, obtained in this paper, the Jarvis model reaches $R^2=0.85$. The data suggest that Jarvis-type models with appropriate parameterization are applicable for stomatal conductance estimation for Pinus cembra when the measurements do not modify the temperature regime. Full article

Global commercial and recreational transport may lead to the unintentional invasion of insect species, which in turn may pose a threat to native organisms. In this study, we aimed to assess whether the economically important pest of Pinus sylvestris L., moth Dendrolimus pini L. (DP), is able to feed on nine other pine species, and how this will affect its survival, performance, growth, and development. We carried out food choice tests and a no-choice laboratory feeding experiment. We found that this insect mostly preferred its prime host, but also Pinus cembra L., Pinus contorta Douglas ex Loudon, Pinus nigra J.F.Arnold, and Pinus ponderosa Douglas ex C.Lawson. The performance test revealed a host-specific response of DP to the host plant. This response was manifested in a large variation in body mass as well as in a decrease or increase in life-history traits, such as fecundity, and wing morphology parameters. However, the larvae’s choice of particular hosts corresponded to the results of the performance test. Larvae more willingly selected food allowing better results in their performance. Larvae achieved better values of growth and development when fed on European and North American pine species or on species with two- and three-needle fascicles. In addition, attractants and repellents in needles of different pine species were chemically analyzed. Variations in the secondary metabolite composition as well as the specific leaf area of different pine species effectively explained the results found in the insects, but the content of sugars and nitrogen remains to be elucidated. We speculate that DP poses a serious threat to large areas of pine forests, if transferred, as it can survive and develop on many economically important tree species in North America and Europe. Full article