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Introduction: In recent years, Norway spruce (Picea abies L.) forests in Central Europe have faced escalating threats from bark beetles, primarily Ips typographus (L.), and other species, such as I. duplicatus (Sahlberg). Outbreaks are partially attributed to weakened tree defense resulting from drought periods induced by climate change. This study examines Norway spruce's physiological and metabolic reactions to acute drought stress during the growing season and evaluates its susceptibility to I. typographus and I. duplicatus. Methodology: In order to induce drought stress, mature Norway spruces had their roots covered with a roof in April 2021, depriving them of water. Control trees were left with free access to natural rainwater. Over 5 months of the growing season, soil water potential, bark temperature, tree trunk circumference, and sap flow were monitored. Roofed trees and controls were sampled in July, August, and September and analyzed for non-structural carbohydrates and the two classes of defensive compounds, phenolics and terpenes. Furthermore, two different bioassays in tubes and boxes were performed using adult I. typographus and I. duplicatus beetles to assess host choice and acceptance. Results: Roofed trees exhibited signs of stress as early as July, resulting in decreased tree trunk and a consequent increase in non-structural carbohydrate content. Defensive metabolites remained largely unaffected except for an increase in diterpenes in September. In bioassays, I. typographus preferred boring into the bark of roofed trees in August in tubes and in September in boxes. This increased tree acceptance correlated with increased levels of soluble carbohydrates in the phloem. I. typographus and I. duplicatus beetles showed higher mobility in boxes in August and September on roofed trees but not in July, even though bark surface temperatures were elevated in roof-covered trees during all three bioassay periods. Conclusion: The study revealed rapid physiological responses of trees to acute drought stress, although not many changes were observed in defense traits. Despite the absence of natural bark beetle attacks, drought trees were more accepted by I. typographus than naturally watered trees. This response may indicate the beetles' preference for trees with phloem of higher nutritional quality induced by the acute drought stress conditions. [ABSTRACT FROM AUTHOR]

Gymnosperms are a very old and small group of plants compared to angiosperms. Contemporary science recognizes about 650 extant conifers worldwide. This review focuses on species of the Pinaceae family found in Europe. There are 23 species from the genera Abies, Larix, Picea, and Pinus. Some of them are widespread in Europe, but others have fragmented and limited distribution and are classified as relic, endemic, or endangered. The aim of this review is providing cumulative information about the variability of needle morpho-anatomy, terpenes, and n-alkanes, as well as the genetics of the Pinaceae species, native to Europe. The first morpho-anatomical examinations of needles were conducted in the 19th century. A lot of species have been investigated up to now, but the population variability of many conifer species is still not known. The composition and abundance of terpenes differ between genera and families but also within the same genus, pointing to their taxonomic importance. n-Alkanes on the needle wax surfaces of conifers are sometimes very useful markers of species and population variability. The most abundant n-alkanes in Abies species are nonacosane (C29), hentriacontane (C31), or heptacosane (C27), whereas in Larix decidua and the majority of Picea species, C31 is predominant. C31 and C29 are the dominant n-alkanes in the genus Pinus. The most extensive population-genetic studies of European representatives of the Pinaceae family have focused on Abies alba, Picea abies, Pinus nigra, and Pinus sylvestris, but also examined endemic species such as Abies borisii-regis, A. cephalonica, A. nebrodensis, and Picea omorika. These studies hold significant practical value in assessing species' evolutionary potential, devising strategies for long-term species conservation, identifying centers of diversity, detecting relict and ancestral populations, unveiling cryptic species and hybrids, and elucidating the taxonomic significance of species. These investigations are of great value not only on the biodiversity level, but also on the levels of ecology, physiology, taxonomy, and evolution. [ABSTRACT FROM AUTHOR]

The genus Crataegus (hawthorn), a member of the Rosaceae family, encompasses several species with broad geographical distribution across the Northern Hemisphere, including Asia, Europe, and the Americas. Hawthorn is recognized as an edible medicinal plant with applications related to strengthening the digestive system, promoting blood circulation, and resolving blood stasis. This study critically summarized the traditional uses, phytochemistry, and pharmacological properties to provide a theoretical basis for further studies on hawthorn and its applications in medicine and food. The available information on hawthorn was gathered from scientific databases (including Google Scholar, Web of Science, PubMed, ScienceDirect, Baidu Scholar, CNKI, online ethnobotanical databases, and ethnobotanical monographs, and considered data from 1952 to 2023). Information about traditional uses, phytochemistry, pharmacology, and safety concerns of the collected data is comprehensively summarized in this paper. The literature review revealed that hawthorn includes more than 1000 species primarily distributed in the northern temperate zone. Traditional uses of hawthorn have lasted for millennia in Asia, Europe, and the Americas. Within the past decade, 337 chemical compounds, including flavonoids, lignans, fatty acids and organic acids, monoterpenoids and sesquiterpenoids, terpenoids and steroids, have been identified from hawthorn. Modern pharmacological studies have confirmed numerous bioactivities, such as cardiovascular system influence, antitumor activity, hepatoprotective activity, antimicrobial properties, immunomodulatory functions, and anti-inflammatory activities. Additionally, evaluations have indicated that hawthorn lacks toxicity. Based on its traditional uses, chemical composition, and pharmacological studies, hawthorn has significant potential as a medicinal and edible plant with a diverse range of pharmacological activities. Traditional uses of the hawthorn include the treatment of indigestion, dysmenorrhea, and osteoporosis. However, modern pharmacological research primarily focuses on its cardiovascular and cerebrovascular system effects, antitumor effects, and liver protection properties. Currently, there is a lack of correlative research involving its traditional uses and pharmacological activities. Moreover, phytochemical and pharmacological research has yet to focus on many types of hawthorn with traditional applications. Therefore, it is imperative to research the genus Crataegus extensively. [Display omitted] • Traditional uses, phytochemistry, pharmacology, and safety concerns of hawthorn. • The medicinal uses and edible value of hawthorn. • The application and medicinal value of hawthorn in ethnopharmacology. • The challenges and opportunities of hawthorn were envisioned. [ABSTRACT FROM AUTHOR]