Abies
Picea
Gymnosperms
Botany
Trees
Plant Somatic Embryogenesis Techniques
2,3-Diketogulonic Acid
Pinus
Plant Stems
Wood
Pervasive influence of large-scale climate in the dynamics of a terrestrial vertebrate community. (1/51)
BACKGROUND: Large-scale climatic variability has been implicated in the population dynamics of many vertebrates throughout the Northern Hemisphere, but has not been demonstrated to directly influence dynamics at multiple trophic levels of any single system. Using data from Isle Royale, USA, comprising time series on the long-term dynamics at three trophic levels (wolves, moose, and balsam fir), we analyzed the relative contributions of density dependence, inter-specific interactions, and climate to the dynamics of each level of the community. RESULTS: Despite differences in dynamic complexity among the predator, herbivore, and vegetation levels, large-scale climatic variability influenced dynamics directly at all three levels. The strength of the climatic influence on dynamics was, however, strongest at the top and bottom trophic levels, where density dependence was weakest. CONCLUSIONS: Because of the conflicting influences of environmental variability and intrinsic processes on population stability, a direct influence of climate on the dynamics at all three levels suggests that climate change may alter stability of this community. Theoretical considerations suggest that if it does, such alteration is most likely to result from changes in stability at the top or bottom trophic levels, where the influence of climate was strongest. (+info)Wind-dispersed pollen mediates postglacial gene flow among refugia. (2/51)
A long-term genetic legacy of refugial isolation has been postulated and was demonstrated for maternal refugial lineages for numerous plant and animal species. The lineages were assumed to have remained separated from each other for several glacial periods. The conifer Abies alba Miller, silver fir, is an excellent model to test whether pollen-mediated gene flow may eliminate the genetic imprints of Pleistocene refugial isolation. Two DNA markers with contrasting modes of inheritance were applied to 100 populations covering the entire range of silver fir in Europe. The markers exhibited each two highly conserved alleles based on an insertion/deletion of 80 bp in the fourth intron of the mitochondrial nad5 gene and on a synonymous substitution in the chloroplast psbC gene. The geographical distribution of the maternally inherited mitochondrial variation supported the existence of at least two refugia with two recolonizing maternal lineages remaining largely separated throughout the range. The cline of the nad5 allele frequencies was much steeper than the one of the two psbC alleles. The psbC cline was as wide as the whole range of the species. Our results provide striking evidence that even a species with very long generation times and heavy pollen grains was able to establish a highly efficient pollen-mediated gene flow between refugia. Therefore we postulate that an exchange of genetic information between refugia by range-wide paternal introgression is possible in wind-pollinated plant species. (+info)Seasonal and perennial changes in the distribution of water in the sapwood of conifers in a sub-frigid zone. (3/51)
An analysis was made of progressive changes in patterns of cavitation in the sapwood of three species of conifer (Larix kaempferi, Abies sachalinensis, and Picea jezoensis) that were growing in a sub-frigid zone. In all three conifers, all tracheids of the newly forming outermost annual ring were filled with water or cytoplasm during the period from May to August. However, many tracheids in the transition zone from earlywood to latewood lost water in September, presumably through drought-induced cavitation. Cavitated tracheids tended to be continuously distributed in a tangential direction. Subsequently, some earlywood tracheids of the outermost annual ring lost water during the period from January to March. This was associated with freeze-thaw cycles. In the second and third annual rings from the cambium of all three conifers, the lumina of most tracheids in the transition zone from earlywood to latewood contained no water. In contrast, some latewood tracheids near the annual ring boundary and many earlywood tracheids retained water in their lumina. The third annual ring had more cavitated tracheids than the second annual ring. Our observations indicated that cavitation progressed gradually in the tracheids of the conifers and that they were never refilled once cavitation had occurred. The region involved in water transport in conifers did not include the entire sapwood and differed among annual rings. (+info)Modeling current and future potential wintering distributions of eastern North American monarch butterflies. (4/51)
Monarch butterflies overwinter in restricted areas in montane oyamel fir forests in central Mexico with specific microclimates that allow the butterflies to survive for up to 5 months. We use ecological niche modeling (ENM) to identify areas adequate for overwintering monarch colonies under both current and future climate scenarios. The ENM approach permits testing and validation of model predictivity, and yields quantitative, testable predictions regarding likely future climate change effects. Our models predicted monarch presence with a high degree of accuracy, and indicated that precipitation and diurnal temperature range were key environmental factors in making locations suitable for monarchs. When we projected monarch distribution onto future climate scenarios (Hadley Centre climate models), we found that conditions were likely to be inadequate across the entire current winter range, particularly owing to increased cool-weather precipitation that could cause increased mortality. This study applies ENM to understanding the seasonal dynamics of a migratory species under climate change, and uses ENM to identify key limiting environmental parameters in species' responses to climate change. (+info)The influence of top-down, bottom-up and abiotic factors on the moose (Alces alces) population of Isle Royale. (5/51)
Long-term, concurrent measurement of population dynamics and associated top-down and bottom-up processes are rare for unmanipulated, terrestrial systems. Here, we analyse populations of moose, their predators (wolves, Canis lupus), their primary winter forage (balsam fir, Abies balsamea) and several climatic variables that were monitored for 40 consecutive years in Isle Royale National Park (544 km2), Lake Superior, USA. We judged the relative importance of top-down, bottom-up and abiotic factors on moose population growth rate by constructing multiple linear regression models, and calculating the proportion of interannual variation in moose population growth rate explained by each factor. Our analysis indicates that more variation in population growth rate is explained by bottom-up than top-down processes, and abiotic factors explain more variation than do bottom-up processes. Surprisingly, winter precipitation did not explain any significant variation in population growth rate. Like that detected for two Norwegian ungulate populations, the relationship between population growth rate and the North Atlantic Oscillation was nonlinear. Although this analysis provides significant insight, much remains unknown: of the models examined, the most parsimonious explain little more than half the variation in moose population growth rate. (+info)Respiratory symptoms and peak expiratory flow rates among furniture-decoration students. (6/51)
This study was designed to evaluate the effects of furniture production, mainly including fir tree (aberia mulleriana), on respiratory health of young workers and to compare the results with those obtained from previous studies. Sixty-four furniture-decoration students (57 males and 7 females) and 62 controls (54 male, 8 female) from different departments in the same school were included into the study. All participants were assessed with a questionnaire (concerning history of occupational exposure, work-related respiratory and other symptoms, smoking history, previous asthma history), full physical examination, spirometric evaluation and chest radiograph. Participants then performed serial monitoring of peak expiratory flow rates (PEFR) at work and away from work within a month. Mean age of students was 20.9 +/- 3.7 years, 20.5 +/- 2.6 years in controls. There was no difference between study and control groups with regard to age, gender, smoking status and previous asthma history. Reported cough (23.4 % vs. 8.1 %) and shortness of breath (18.8 % vs. 6.5 %) were significantly higher in furniture-decoration students than in controls (p = 0.016 and p = 0.034, respectively). Furniture-decoration students had higher conjunctivitis (34.4 % vs. 9.7 %, p = 0.001) and rhinitis (34.4 % vs. 19.4 %, p = 0.044) history when compared with controls. Both students and controls were normal in terms of respiratory examination. PEF recordings were performed for approximately one month. Diurnal variability greater than 20 % was seen in 12/64 (18.7 %) of students at work, whereas it was detected in 4/62 (6.4 %) of controls (p = 0.034). When comparing for the presence of diurnal variability greater than 20 % in weekends, no difference was found between groups (p = 0.457). In conclusion, early detection of work-related respiratory changes by serial monitoring of peak expiratory flows should save the workers from hazardous respiratory effects of the furniture production, especially in young population. (+info)Differentiation of terminal latewood tracheids in silver fir trees during autumn. (7/51)
BACKGROUND AND AIMS: The differentiation of terminal latewood tracheids of silver fir (Abies alba) trees grown in Slovenia was investigated in autumn/winter 2001/2002. METHODS: The experimental trees were divided into three groups: one with narrow annual rings, width less than 1 mm; one with annual ring widths between 1 and 4 mm; and one group with broad rings larger than 4 mm. The differentiation of terminal latewood tracheids was investigated by light-, electron- and UV-microscopy in tissues sampled in October and November 2001 and March 2002. KEY RESULTS: In the middle of October, cambial divisions did not occur any more in any of the trees. In trees with narrow annual rings, cell wall deposition as well as lignification were completed in terminal latewood tracheids at this date, whereas in trees with annual ring widths of more than 1 mm these processes still continued. Electron microscopy as well as UV microscopy revealed an unlignified inner S(2) layer and the absence of S(3) and warty layers. With increasing distance from the cambium, wall formation and lignification gradually appeared to be completed. Samples of all trees taken in the middle of November only contained differentiated terminal latewood tracheids. At the structural and lignin topochemical level, November and March samples showed completed differentiation of walls of terminal latewood tracheids. CONCLUSIONS: In trees with broader annual rings, the final steps of differentiation of the youngest latewood tracheids near the cambium still continued during autumn, but were finished prior to winter. It was concluded from structural observations that duration of cambial activity is longer in trees with broad annual rings than in trees with narrow rings. (+info)Unexpectedly high bacterial diversity in arctic tundra relative to boreal forest soils, revealed by serial analysis of ribosomal sequence tags. (8/51)
Arctic tundra and boreal forest soils have globally relevant functions that affect atmospheric chemistry and climate, yet the bacterial composition and diversity of these soils have received little study. Serial analysis of ribosomal sequence tags (SARST) and denaturing gradient gel electrophoresis (DGGE) were used to compare composite soil samples taken from boreal and arctic biomes. This study comprises an extensive comparison of geographically distant soil bacterial communities, involving the analysis of 12,850 ribosomal sequence tags from six composite soil samples. Bacterial diversity estimates were greater for undisturbed arctic tundra soil samples than for boreal forest soil samples, with the highest diversity associated with a sample from an extreme northern location (82(o)N). The lowest diversity estimate was obtained from an arctic soil sample that was disturbed by compaction and sampled from a greater depth. Since samples from the two biomes did not form distinct clusters on the basis of SARST data and DGGE fingerprints, factors other than latitude likely influenced the phylogenetic compositions of these communities. The high number of ribosomal sequences analyzed enabled the identification of possible cosmopolitan and endemic bacterial distributions in particular soils. (+info)"Abies" is a genus of evergreen trees that are commonly known as firs. They belong to the family Pinaceae and are native to the northern hemisphere, primarily in North America, Europe, and Asia. These trees are characterized by their needle-like leaves, which are flat and shiny, and their conical-shaped crowns.
Firs have been used for various purposes throughout history, including timber production, Christmas tree farming, and ornamental landscaping. Some species of firs also have medicinal properties, such as the use of Abies balsamea (balsam fir) in traditional medicine to treat respiratory ailments and skin conditions. However, it's important to note that the medical use of firs should be done under the guidance of a healthcare professional, as improper use can lead to adverse effects.
"Picea" is not a medical term. It is the genus name for a group of evergreen coniferous trees commonly known as spruces, which are part of the pine family (Pinaceae). These trees are native to the northern hemisphere and are widely distributed in North America, Europe, and Asia.
While spruce trees have some medicinal uses, such as extracts from the needles being used in traditional medicine for their antimicrobial and anti-inflammatory properties, "Picea" itself is not a medical term or concept.
Gymnosperms are a group of seed-producing plants that include conifers, cycads, Ginkgo, and gnetophytes. The name "gymnosperm" comes from the Greek words "gymnos," meaning naked, and "sperma," meaning seed. This refers to the fact that the seeds of gymnosperms are not enclosed within an ovary or fruit, but are exposed on the surface of modified leaves called cones or strobili.
Gymnosperms are vascular plants, which means they have specialized tissues for transporting water and nutrients throughout the plant. They are also heterosporous, meaning that they produce two types of spores: male microspores and female megaspores. The microspores develop into male gametophytes, which produce sperm cells, while the megaspores develop into female gametophytes, which produce egg cells.
Gymnosperms are an important group of plants that have been around for millions of years. They are adapted to a wide range of environments, from temperate forests to deserts and high mountain ranges. Many gymnosperms are evergreen, with needle-like or scale-like leaves that are able to resist drought and cold temperatures.
Conifers, which include trees such as pines, firs, spruces, and redwoods, are the most diverse and widespread group of gymnosperms. They are characterized by their woody cones and needle-shaped leaves. Cycads are another group of gymnosperms that are found in tropical and subtropical regions. They have large, stiff leaves and produce large seeds that are enclosed in a fleshy covering. Ginkgo is a unique gymnosperm that has been around for over 200 million years. It is a deciduous tree with fan-shaped leaves and large, naked seeds.
Gnetophytes are a small group of gymnosperms that include the ephedra, welwitschia, and gnetum. They have unique features such as vessels in their wood and motile sperm cells, which are not found in other gymnosperms.
Overall, gymnosperms are an important group of plants that have adapted to a wide range of environments and play a crucial role in many ecosystems.
Botany is the scientific study of plants, encompassing various disciplines such as plant structure, function, evolution, diversity, distribution, ecology, and application. It involves examining different aspects like plant anatomy, physiology, genetics, molecular biology, systematics, and ethnobotany. The field of botany has contributed significantly to our understanding of the natural world, agriculture, medicine, and environmental conservation.
I'm sorry for any confusion, but "trees" is not a medical term. It is a common term used in various fields, including biology, ecology, and dendrology, to refer to a woody perennial plant with a single stem or trunk that supports branches and leaves in most species.
If you have any questions related to medical terminology or health-related topics, please provide more context so I can offer an accurate and helpful response.
Coniferophyta is a division of vascular plants that includes the conifers. It is an informal name and not commonly used in modern taxonomy, but it can still be found in some older textbooks and resources. The more widely accepted classification system places conifers within the gymnosperms, which are a group of seed-bearing plants characterized by the absence of fruits or flowers.
Conifers are a diverse group of woody plants that include trees and shrubs such as pines, firs, spruces, hemlocks, cedars, and redwoods. They are known for their cone-bearing seeds and needle-shaped leaves, which are often evergreen. Conifers are widely distributed throughout the world and play important ecological roles in many ecosystems, particularly in temperate and boreal forests.
In summary, while "Coniferophyta" is an outdated term for the division that includes conifers, it refers to a group of plants characterized by their cone-bearing seeds and needle-shaped leaves. Modern classification systems place conifers within the gymnosperms.
Plant somatic embryogenesis techniques refer to the scientific methods used to induce and produce embryos from plant somatic cells, which are not involved in sexual reproduction. These techniques involve the culture of isolated plant cells or tissues on nutrient-rich media under controlled conditions that promote embryo development. The resulting embryos can be germinated into plants, which are genetically identical to the parent plant, a process known as clonal propagation.
Somatic embryogenesis techniques have various applications in plant biotechnology, including large-scale propagation of elite varieties, genetic transformation, and cryopreservation of plant genetic resources. The ability to produce embryos from somatic cells also has potential implications for understanding the fundamental mechanisms of plant development and evolution.
2,3-Diketogulonic acid is not a commonly used medical term or a compound that has direct relevance to medical diagnosis, treatment, or disease. It is a chemical compound that is a derivative of glucose metabolism and can be found in certain foods and biological samples.
In biochemistry, 2,3-Diketogulonic acid is an intermediate product formed during the breakdown of glucose in the body. Specifically, it is produced when the aldose reductase enzyme converts D-glucose to D-sorbitol, and then the sorbitol dehydrogenase enzyme further metabolizes D-sorbitol to 2,3-Diketogulonic acid.
While 2,3-Diketogulonic acid itself is not a medically significant compound, its presence in certain foods or biological samples may be used as an indicator of various biochemical processes or metabolic disorders. For example, elevated levels of 2,3-Diketogulonic acid in urine have been associated with diabetes and other metabolic diseases.
Therefore, while not a medical definition per se, 2,3-Diketogulonic acid is a chemical compound that can be relevant to certain medical and biochemical contexts.
I apologize for any confusion, but "Pinus" is not a medical term. It is the genus name for a group of plants commonly known as pine trees, which belong to the family Pinaceae in the kingdom Plantae. These evergreen coniferous resinous trees are widely distributed throughout the Northern Hemisphere, with some species also found in the Southern Hemisphere.
If you have any medical terms or concepts that you would like me to define or explain, please feel free to ask!
A plant stem is not typically defined in a medical context, but rather in the field of botany. However, I can certainly provide a general biological definition for you.
In plants, stems are organs that serve primarily as support structures, holding leaves, flowers, and fruits aloft where they can receive sunlight and exchange gases. They also act as conduits, transporting water, nutrients, and sugars made during photosynthesis between the roots and shoots of a plant.
The stem is usually composed of three main tissue systems: dermal, vascular, and ground. The dermal tissue system forms the outermost layer(s) of the stem, providing protection and sometimes participating in gas exchange. The vascular tissue system contains the xylem (which transports water and nutrients upward) and phloem (which transports sugars and other organic compounds downward). The ground tissue system, located between the dermal and vascular tissues, is responsible for food storage and support.
While not a direct medical definition, understanding the structure and function of plant stems can be relevant in fields such as nutrition, agriculture, and environmental science, which have implications for human health.
I'm sorry for any confusion, but "Wood" is not a medical term. It is a common name for various hard, fibrous tissues that make up the trunks and branches of trees and shrubs, as well as a term used for a wide range of items made from these materials. If you have any medical concerns or questions, I would be happy to try and help answer those for you.
Abietanes are a subclass of diterpenes, which are a type of organic compound consisting of four isoprene units and having the chemical formula C20H32. Diterpenes are synthesized by a wide variety of plants and some animals, and they have diverse biological activities.
Abietanes are characterized by a distinctive carbon skeleton that contains three six-membered rings arranged in a linear fashion, with the fourth ring being a five-membered ring. This particular structure is derived from geranylgeranyl pyrophosphate (GGPP), a precursor to many diterpenes.
Abietanes are found in various natural sources, including pine resin, where they exist as resin acids such as abietic acid, pimaric acid, and isopimaric acid. These compounds have been studied for their potential medicinal properties, including anti-inflammatory, antimicrobial, and anticancer activities. However, more research is needed to fully understand the therapeutic potential of abietanes and to develop safe and effective treatments based on these compounds.
Terpenes are a large and diverse class of organic compounds produced by a variety of plants, including cannabis. They are responsible for the distinctive aromas and flavors found in different strains of cannabis. Terpenes have been found to have various therapeutic benefits, such as anti-inflammatory, analgesic, and antimicrobial properties. Some terpenes may also enhance the psychoactive effects of THC, the main psychoactive compound in cannabis. It's important to note that more research is needed to fully understand the potential medical benefits and risks associated with terpenes.