Gymnosperms: Gymnosperms are a group of vascular plants whose seeds are not enclosed by a ripened ovary (fruit), in contrast to ANGIOSPERMS whose seeds are surrounded by an ovary wall. The seeds of many gymnosperms (literally, "naked seed") are borne in cones and are not visible. Taxonomists now recognize four distinct divisions of extant gymnospermous plants (CONIFEROPHYTA; CYCADOPHYTA; GINKGOPHYTA; and GNETOPHYTA).Angiosperms: Members of the group of vascular plants which bear flowers. They are differentiated from GYMNOSPERMS by their production of seeds within a closed chamber (OVARY, PLANT). The Angiosperms division is composed of two classes, the monocotyledons (Liliopsida) and dicotyledons (Magnoliopsida). Angiosperms represent approximately 80% of all known living plants.Picea: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. They are evergreen, pyramidal trees with whorled branches and thin, scaly bark. Each of the linear, spirally arranged leaves is jointed near the stem on a separate woody base.Cycas: A plant genus of the family Cycadaceae, order Cycadales, class Cycadopsida, division CYCADOPHYTA of palm-like trees. It is a source of CYCASIN, the beta-D-glucoside of methylazoxymethanol.Coniferophyta: A plant division of GYMNOSPERMS consisting of cone-bearing trees and shrubs.Pinus: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. They are evergreen trees mainly in temperate climates.Taxus: Genus of coniferous yew trees or shrubs, several species of which have medicinal uses. Notable is the Pacific yew, Taxus brevifolia, which is used to make the anti-neoplastic drug taxol (PACLITAXEL).Pinaceae: A plant family of the order Pinales, class Pinopsida, division Coniferophyta, known for the various conifers.Ginkgo biloba: The only specie of the genus Ginkgo, family Ginkgoacea. It is the source of extracts of medicinal interest, especially Egb 761. Ginkgo may refer to the genus or species.Pinus taeda: A plant species of the genus PINUS which is the subject of genetic study.Cycadophyta: A division of GYMNOSPERMS which look like palm trees (ARECACEAE) but are more closely related to PINUS. They have large cones and large pinnate leaves and are sometimes called cycads, a term which may also refer more narrowly to cycadales or CYCAS.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Zamiaceae: A plant family of the order Cycadales, class Cycadopsida, division CYCADOPHYTA.Ephedra: A plant genus of the family Ephedraceae, order Ephedrales, class Gnetopsida, division Gnetophyta.Ferns: Seedless nonflowering plants of the class Filicinae. They reproduce by spores that appear as dots on the underside of feathery fronds. In earlier classifications the Pteridophyta included the club mosses, horsetails, ferns, and various fossil groups. In more recent classifications, pteridophytes and spermatophytes (seed-bearing plants) are classified in the Subkingdom Tracheobionta (also known as Tracheophyta).Trees: Woody, usually tall, perennial higher plants (Angiosperms, Gymnosperms, and some Pterophyta) having usually a main stem and numerous branches.Selaginellaceae: A plant family of the order Selaginellales, class Lycopodiopsida, division Lycopodiophyta, subkingdom Tracheobionta. Members contain bilobetin. The rarely used common name of resurrection plant is mainly used with CRATEROSTIGMA.Genes, Plant: The functional hereditary units of PLANTS.Ovule: The element in plants that contains the female GAMETOPHYTES.Ocotea: A plant genus in the LAURACEAE family. The common name of stinkwood is also used for Zieria (RUTACEAE).Cambium: A layer of living cells between the bark and hardwood that each year produces additional wood and bark cells, forming concentric growth rings.Pseudotsuga: A plant genus in the family PINACEAE, order Pinales, class Pinopsida, division Coniferophyta. They are coniferous evergreen trees with long, flat, spirally arranged needles that grow directly from the branch.Lignin: The most abundant natural aromatic organic polymer found in all vascular plants. Lignin together with cellulose and hemicellulose are the major cell wall components of the fibers of all wood and grass species. Lignin is composed of coniferyl, p-coumaryl, and sinapyl alcohols in varying ratios in different plant species. (From Merck Index, 11th ed)Cupressaceae: A plant family of the order Pinales, class Pinopsida, division Coniferophyta (conifers). They are mainly resinous, aromatic evergreen trees.DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Gnetum: A plant genus of the family Gnetaceae, order Gnetales class Gnetopsida, division GNETOPHYTA. Members contain STILBENES and benzylisoquinoline alkaloids.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Genome, Chloroplast: The genetic complement of CHLOROPLASTS as represented in their DNA.Genome, Plant: The genetic complement of a plant (PLANTS) as represented in its DNA.Bryophyta: A division of the plant kingdom. Bryophyta contains the subdivision, Musci, which contains the classes: Andreaeopsida, BRYOPSIDA, and SPHAGNOPSIDA.Thysanoptera: An order of very small, fringed-wing INSECTS including many agricultural pests.Cunninghamia: A plant genus of the family TAXODIACEAE. Members contain DITERPENES.Pinus sylvestris: A plant species of the genus PINUS which is the source of pinosylvin. It is sometimes called Scotch pine or Scots pine, which is also a common name for other species of this genus.Phloem: Plant tissue that carries nutrients, especially sucrose, by turgor pressure. Movement is bidirectional, in contrast to XYLEM where it is only upward. Phloem originates and grows outwards from meristematic cells (MERISTEM) in the vascular cambium. P-proteins, a type of LECTINS, are characteristically found in phloem.Seeds: The encapsulated embryos of flowering plants. They are used as is or for animal feed because of the high content of concentrated nutrients like starches, proteins, and fats. Rapeseed, cottonseed, and sunflower seed are also produced for the oils (fats) they yield.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.DNA Shuffling: The use of DNA recombination (RECOMBINATION, GENETIC) to prepare a large gene library of novel, chimeric genes from a population of randomly fragmented DNA from related gene sequences.Viridiplantae: A monophyletic group of green plants that includes all land plants (EMBRYOPHYTA) and all green algae (CHLOROPHYTA and STREPTOPHYTA).Fossils: Remains, impressions, or traces of animals or plants of past geological times which have been preserved in the earth's crust.Extinction, Biological: The ceasing of existence of a species or taxonomic groups of organisms.Cryptomeria: A plant genus of the family TAXODIACEAE. Its POLLEN is one of the major ALLERGENS.Wood: A product of hard secondary xylem composed of CELLULOSE, hemicellulose, and LIGNANS, that is under the bark of trees and shrubs. It is used in construction and as a source of CHARCOAL and many other products.Seed Dispersal: The various physical methods which include wind, insects, animals, tension, and water, by which a plant scatters its seeds away from the parent plant.Flowers: The reproductive organs of plants.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.DNA, Chloroplast: Deoxyribonucleic acid that makes up the genetic material of CHLOROPLASTS.RNA, Plant: Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Expressed Sequence Tags: Partial cDNA (DNA, COMPLEMENTARY) sequences that are unique to the cDNAs from which they were derived.Diterpenes, Kaurane: A group of DITERPENES cyclized into four rings.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Pollen: The fertilizing element of plants that contains the male GAMETOPHYTES.
Process and current status of the epidemiologic studies on cedar pollinosis in Japan. (1/132)
This paper reviews the present situation and future aspects of epidemiologic studies on Japanese cedar pollinosis. Increase of allergic rhinitis patients is observed in both the Patient Survey and the Reports on the Surveys of Social Medical Care Insurance Services, however, these surveys are conducted when cedar pollens do not pollute the air. Many have reported on the prevalence of pollinosis in limited areas but only a few nationwide epidemiologic surveys have been conducted. Most of the studies were conducted at special medical facilities such as university hospitals. There is a high possibility that patients who visit the specific facilities do not exactly represent the actual number of patients and epidemiologic pictures of pollinosis in Japan. The rapid advances in laboratory test methods may change the diagnostic criteria and increase the number of reported patients. Therefore, the prevalence of Japanese cedar pollinosis in Japan has not been determined yet. Determination of the prevalence of cedar pollinosis and description of the epidemiologic pictures constitute the essential steps toward the control of this clinical entity. Thus it is necessary to conduct an epidemiologic survey on Japanese representative samples with a standardized survey form with clear and concise diagnostic criteria. (+info)Genes expressed in Pinus radiata male cones include homologs to anther-specific and pathogenesis response genes. (2/132)
We describe the isolation and characterization of 13 cDNA clones that are differentially expressed in male cones of Pinus radiata (D. Don). The transcripts of the 13 genes are expressed at different times between meiosis and microspore mitosis, timing that corresponds to a burst in tapetal activity in the developing anthers. In situ hybridization showed that four of the genes are expressed in the tapetum, while a fifth is expressed in tetrads during a brief developmental window. Six of the seven cDNAs identified in database searches have striking similarity to genes expressed in angiosperm anthers. Seven cDNAs are homologs of defense and pathogen response genes. The cDNAs identified are predicted to encode a chalcone-synthase-like protein, a thaumatin-like protein, a serine hydrolase thought to be a putative regulator of programmed cell death, two lipid-transfer proteins, and two homologs of the anther-specific A9 genes from Brassica napus and Arabidopsis. Overall, our results support the hypothesis that many of the reproductive processes in the angiosperms and gymnosperms were inherited from a common ancestor. (+info)Rapid expansion of microsatellite sequences in pines. (3/132)
Microsatellite persistence time and evolutionary change was studied among five species of pines, which included a pair of closely related species (Pinus sylvestris and Pinus resinosa) in the subgenus Pinus, their relative Pinus radiata, and another closely related species pair (Pinus strobus and Pinus lambertiana) in the subgenus Strobus. The effective population sizes of these species are known to have ranged from the very small bottlenecks of P. resinosa to vast populations of P. sylvestris. This background allowed us to place the microsatellite evolution in a well-defined phylogenetic setting. Of 30 loci originating from P. strobus and P. radiata, we were able to consistently amplify 4 in most of the these pine species. These priming sites had been conserved for over 100 Myr. The four microsatellites were sequenced in the five species. Flanking sequences were compared to establish that the loci were orthologous. All microsatellites had persisted in these species, despite very different population sizes. We found a recent microsatellite duplication: a closely related pair of loci in P. strobus, where the other four species had just one locus. On two independent occasions, the repeat area of this same microsatellite (locus RPS 105a/b) had grown from a very low repeat number to 15 or 17 in the last 10-25 Myr. Other parts of the same compound microsatellite had remained virtually unchanged. Locus PR 4.6 is known to be polymorphic in both P. radiata and P. sylvestris, but the polymorphism in the two species is due to different motifs. The very large pine genomes are highly repetitive, and microsatellite loci also occur as gene families. (+info)Seed plant phylogeny: Demise of the anthophyte hypothesis? (4/132)
Recent molecular phylogenetic studies indicate, surprisingly, that Gnetales are related to conifers, or even derived from them, and that no other extant seed plants are closely related to angiosperms. Are these results believable? Is this a clash between molecules and morphology? (+info)Seed plant phylogeny inferred from all three plant genomes: monophyly of extant gymnosperms and origin of Gnetales from conifers. (5/132)
Phylogenetic relationships among the five groups of extant seed plants are presently quite unclear. For example, morphological studies consistently identify the Gnetales as the extant sister group to angiosperms (the so-called "anthophyte" hypothesis), whereas a number of molecular studies recover gymnosperm monophyly, and few agree with the morphology-based placement of Gnetales. To better resolve these and other unsettled issues, we have generated a new molecular data set of mitochondrial small subunit rRNA sequences, and have analyzed these data together with comparable data sets for the nuclear small subunit rRNA gene and the chloroplast rbcL gene. All nuclear analyses strongly ally Gnetales with a monophyletic conifers, whereas all mitochondrial analyses and those chloroplast analyses that take into account saturation of third-codon position transitions actually place Gnetales within conifers, as the sister group to the Pinaceae. Combined analyses of all three genes strongly support this latter relationship, which to our knowledge has never been suggested before. The combined analyses also strongly support monophyly of extant gymnosperms, with cycads identified as the basal-most group of gymnosperms, Ginkgo as the next basal, and all conifers except for Pinaceae as sister to the Gnetales + Pinaceae clade. According to these findings, the Gnetales may be viewed as extremely divergent conifers, and the many morphological similarities between angiosperms and Gnetales (e.g., double fertilization and flower-like reproductive structures) arose independently. (+info)Phylogeny of seed plants based on all three genomic compartments: extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers. (6/132)
Efforts to resolve Darwin's "abominable mystery"-the origin of angiosperms-have led to the conclusion that Gnetales and various fossil groups are sister to angiosperms, forming the "anthophytes." Morphological homologies, however, are difficult to interpret, and molecular data have not provided clear resolution of relationships among major groups of seed plants. We introduce two sequence data sets from slowly evolving mitochondrial genes, cox1 and atpA, which unambiguously reject the anthophyte hypothesis, favoring instead a close relationship between Gnetales and conifers. Parsimony- and likelihood-based analyses of plastid rbcL and nuclear 18S rDNA alone and with cox1 and atpA also strongly support a gnetophyte-conifer grouping. Surprisingly, three of four genes (all but nuclear rDNA) and combined three-genome analyses also suggest or strongly support Gnetales as derived conifers, sister to Pinaceae. Analyses with outgroups screened to avoid long branches consistently identify all gymnosperms as a monophyletic sister group to angiosperms. Combined three- and four-gene rooted analyses resolve the branching order for the remaining major groups-cycads separate from other gymnosperms first, followed by Ginkgo and then (Gnetales + Pinaceae) sister to a monophyletic group with all other conifer families. The molecular phylogeny strongly conflicts with current interpretations of seed plant morphology, and implies that many similarities between gnetophytes and angiosperms, such as "flower-like" reproductive structures and double fertilization, were independently derived, whereas other characters could emerge as synapomorphies for an expanded conifer group including Gnetales. An initial angiosperm-gymnosperm split implies a long stem lineage preceding the explosive Mesozoic radiation of flowering plants and suggests that angiosperm origins and homologies should be sought among extinct seed plant groups. (+info)Detection of intracellular bacteria in the buds of Scotch pine (Pinus sylvestris L.) by in situ hybridization. (7/132)
Bacterial isolates were obtained from pine (Pinus sylvestris L.) tissue cultures and identified as Methylobacterium extorquens and Pseudomonas synxantha. The existence of bacteria in pine buds was investigated by 16S rRNA in situ hybridization. Bacteria inhabited the buds of every tree examined, primarily colonizing the cells of scale primordia and resin ducts. (+info)Hot spots, indicator taxa, complementarity and optimal networks of taiga. (8/132)
If hot spots for different taxa coincide, priority-setting surveys in a region could be carried out more cheaply by focusing on indicator taxa. Several previous studies show that hot spots of different taxa rarely coincide. However, in tropical areas indicator taxa may be used in selecting complementary networks to represent biodiversity as a whole. We studied beetles (Coleoptera), Heteroptera, polypores or bracket fungi (Polyporaceae) and vascular plants of old growth boreal taiga forests. Optimal networks for Heteroptera maximized the high overall species richness of beetles and vascular plants, but these networks were least favourable options for polypores. Polypores are an important group indicating the conservation value of old growth taiga forests. Random selection provided a better option. Thus, certain groups may function as good indicators for maximizing the overall species richness of some taxonomic groups, but all taxa should be examined separately. (+info)AngiospermsNaked seedSeedsReproductiveEvolutionary significanceTallestPhylogenyCarboniferousPlantsDominated the landscapeLifeLearnPresentConifersCycadsSeed fernsBiologyPollinationOvaryConesGinkgoGnetalesHeterosporousGnetophytaGnetumVascularGinkgophytaMeaning seedPlantHaploidBotanyCharacteristicsBryophytesGroup of gymnospermsPinusFossilCladePhylaWoodyGnetophytesClassification of GymnospermsEvolutionaryMonophyleticGymnospermaeFertilizationPhylogeneticExtant gymnospermGametophyteConeExtinctTaxaUnisexualStemFruitsMicrosporophyllsGenomeSpecies of gymnospermsLife cycleXylemDifferent types of sporesOvulesConsistMegasporophyllsFeatures of GymnospermsStemsShrubsAbundantTerrestrialSpermatophytesPollen grainPineMesozoic
- Grasses are angiosperms, however, trees are typically referred to as gymnosperms.The difference between these types of plants is that angiosperms have ovaries, while gymnosperms do not. (accentnatural.com)
- Although pollen of some flowers can be carried by the wind to a willing stigma, grass angiosperms and gymnosperms depend upon the wind to carry their pollen from one plant to another. (accentnatural.com)
- Gymnosperm means naked seed. (toppr.com)
- Gymnosperms ("naked seed") are a diverse group of seed plants and are paraphyletic. (openstax.org)
- Gymnosperm characteristics include naked seeds, separate female and male gametes, pollination by wind, and tracheids, which transport water and solutes in the vascular system. (openstax.org)
- Strobilus or cone is the reproductive structure of gymnosperms. (toppr.com)
- Gymnosperms have an evolutionary significance and show some unique features. (toppr.com)
- Sequoia is a gymnosperm which is one of the tallest tree species. (toppr.com)
- However, there was not a molecular phylogeny of gymnosperms represented by extensive sampling at the genus level, and most published phylogenies of this group were constructed based on cytoplasmic DNA markers and/or the multi-copy nuclear ribosomal DNA. (semanticscholar.org)
- Phylogeny of seed plants based on all three genomic compartments: extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers. (semanticscholar.org)
- The earliest reliable record of gymnosperms dates their appearance to the Carboniferous period (359-299 million years ago). (openstax.org)
- The group of plants that we call gymnosperms is major evidence for this. (toppr.com)
- Gymnosperm plants are heterosporous. (toppr.com)
- In the Mesozoic era (251-65.5 million years ago), gymnosperms dominated the landscape. (openstax.org)
- The following figure shows the life cycle of a gymnosperm. (toppr.com)
- Although the "gymnosperms" were at one time treated as one closely allied group, many modern workers recognize several major groups, which include the commonly known conifers, cycads, and ginkgos, and the lesser known gnetopsids group, extinct progymnosperms, and extinct seed ferns. (washington.edu)
- The conifers are the most common and abundant group of "gymnosperms" alive today. (washington.edu)
- Studies of their deoxyribonucleic acid (DNA) has shown that the gymnosperms consist of four major, related groups: conifers, cycads, ginkgo, and gnetophytes. (encyclopedia.com)
- Known as conifers , members of the division Pinophyta are among the most diverse of the gymnosperms, with some 630 living species across six families. (britannica.com)
- The gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes. (wikipedia.org)
- By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species). (wikipedia.org)
- Conifers are by far the most abundant extant group of gymnosperms with six to eight families, with a total of 65-70 genera and 600-630 species (696 accepted names). (wikipedia.org)
- Conifers are called gymnosperms . (education.com)
- Note that throughout this paper "gymnosperms" specifies only the approximately 1000 extant species within cycads, Ginkgo , Gnetales, and conifers. (hindawi.com)
- Unlike modern wind-pollinated conifers and Ginkgo, cycads are unusual in that they are an ancient group of gymnosperms pollinated by insects, such as beetles and rarely thrips. (eurekalert.org)
- The combined analyses also strongly support monophyly of extant gymnosperms, with cycads identified as the basal-most group of gymnosperms, Ginkgo as the next basal, and all conifers except for Pinaceae as sister to the Gnetales + Pinaceae clade. (pnas.org)
- Extant seed plants (angiosperms and four groups of gymnosperms: cycads, conifers, Ginkgo , and Gnetales) differ from all other living land plants by several characters, the most notable, of course, being reproduction via seeds. (pnas.org)
- These last studies either place Gnetales as sister to conifers within a monophyletic gymnosperms ( 16 - 19 ) or are unable to resolve overall issues of gymnosperm phylogeny because cycads and Ginkgo were not sampled ( 20 , 21 ). (pnas.org)
- The tortoise and the hare: ecology of angiosperm dominance and gymnosperm persistence BOND, W. J. 1989-03-01 00:00:00 Gymnosperms, and conifers in particular, are sometimes very productive trees yet angiosperms dominate most temperate and tropical vegetation. (deepdyve.com)
- Gymnosperms, and conifers in particular, are sometimes very productive trees yet angiosperms dominate most temperate and tropical vegetation. (deepdyve.com)
- Currently the database provides basic information for all species and higher-ranked taxa of the gymnosperms, i.e., conifers, cycads, and their allies. (equisetites.de)
- The existence of gymnosperm-insect associations during the preangiospermous Mesozoic is evidenced by mouthparts capable of reaching and imbibing pollination drops or similar fluids, availability of pollen types consistent with entomophily, and opportunities for related consumption of pollen, seeds, and reproductively associated tissues in major seed-plant groups, namely seed ferns, conifers, cycads, bennettitaleans, and gnetaleans. (si.edu)
- Among them, the largest group of living gymnosperms is Conifers while ginkgo is a single living plant species which is found in China. (biologyeducare.com)
- The family of gymnosperms consist of conifers, the cycads, the gnetophytes, and the species of Gynkgophyta division and Ginkgo biloba. (byjus.com)
- Conifers are key representatives of gymnosperms and the sheer size of their genomes represents a significant challenge for characterization, sequencing and assembling. (biomedcentral.com)
- Taken together, these results indicate that much genomic evolution has occurred in the seed plant lineage before the split between gymnosperms and angiosperms, and that the pace of evolution of the genome macro-structure has been much slower in the gymnosperm lineage leading to extent conifers than that seen for the same period of time in flowering plants. (biomedcentral.com)
- Chaw S-M., C.L. Parkinson, Y. Cheng, T.M. Vincent and J. D. Palmer (2000) Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from conifers Proceedings of the National Academy of Sciences of the United States of America 97:4086-4091 Wang, Z-Q (2004). (wikipedia.org)
- Most "gymnosperms" are wind-pollinated except for cycads, which are beetle-pollinated. (washington.edu)
- The cycads are slow-growing dioecious (species with individuals that are either male or female) gymnosperms, the microsporangia (potential pollen) and megasporangia (potential ovules) occurring on different individual sporophytes. (britannica.com)
- Combined three- and four-gene rooted analyses resolve the branching order for the remaining major groups-cycads separate from other gymnosperms first, followed by Ginkgo and then (Gnetales + Pinaceae) sister to a monophyletic group with all other conifer families. (pnas.org)
- The fossil record of gymnosperms includes many distinctive taxa that do not belong to the four modern groups, including seed-bearing trees that have a somewhat fern-like vegetative morphology (the so-called "seed ferns" or pteridosperms. (wikipedia.org)
- Fossil gymnosperms include many that do not belong to the four modern groups, including the so-called "seed ferns" ( Pteridosperms ) and the "cycadeoids" ( Bennettitales ). (wikipedia.org)
- This book presents comprehensive and up-to-date knowledge of gymnosperms, their morphology, anatomy, reproductive biology, cytology and phylogeny. (foyles.co.uk)
- Insect-mediated pollination in gymnosperms and potentially prior to the rise of flowering plants is critical for understanding not only the complex biology of these plants today but also the ecology of pre-angiospermous ecosystems and the history of pollination specializations on gymnosperms. (eurekalert.org)
- Gymnosperms were among the first plants to colonize the land, and adaptations to the Earth's terrestrial biome pervade their biology. (reference.com)
- D.M. Bruns Stockrahm , Biosciences Department, Minnesota State University Moorhead: Organismal Biology, Gymnosperms . (equisetites.de)
- Use this Biology and Botany quiz entitled The Gymnosperms and Angiosperms Quiz to test your knowledge of their classes and characteristics and the fascinating world of plants. (zaneeducation.com)
- Use these Biology and Botany videos entitled Algae, Fungi, Bryophytes, Ferns, Gymnosperms and Angiosperms to study to explore their classes and characteristics and dicover the fascinating world of plants in this thorough study of algae, fungi, bryophytes ad ferns, gymnosperms, and angiosperms. (zaneeducation.com)
- Gymnosperms" are a diverse and paraphyletic group of seed plants, and can be characterized by the following features: exposed seeds formed in cones, pollination occurring by pollen landing directly on the ovules, generally one fertilization event in the ovules, and tracheids as the water-conducting cells (xylem) in the vascular system. (washington.edu)
- It has been suggested that during the mid-Mesozoic era, pollination of some extinct groups of gymnosperms was by extinct species of scorpionflies that had specialized proboscis for feeding on pollination drops. (wikipedia.org)
- The scorpionflies likely engaged in pollination mutualisms with gymnosperms, long before the similar and independent coevolution of nectar-feeding insects on angiosperms. (wikipedia.org)
- Gymnosperm-insect interactions, on the other hand, are far less well understood, particularly in terms of pollination modes. (eurekalert.org)
- Gymnosperms are almost universally wind-pollinated plants, while many angiosperms utilize insects, mammals or birds to achieve cross-pollination. (reference.com)
- The gymnosperms have to work with natural agents for their pollination. (differencebetween.net)
- In a new study published in the April issue of Applications in Plant Sciences (available for free viewing at http://www.bioone.org/doi/pdf/10.3732/apps.1300008 ), graduate student Natalie Prior and her colleagues demonstrate the suitability of proteomics in determining the composition of gymnosperm pollination drops. (bio-medicine.org)
- Gymnosperm characteristics include naked seeds, separate female and male gametes, pollination by wind, and tracheids, which transport water and solutes in the vascular system. (openstax.org)
- How does pollination occur in gymnosperms? (bartleby.com)
- Gymnosperms are a group of plants that share one common characteristic: they bear seeds, but their seeds do not develop within an ovary. (encyclopedia.com)
- For this reason, gymnosperms were long thought to be an evolutionary precursor to the angiosperms, which are seed plants that enclose their seeds in an ovary and that are vastly more diverse than gymnosperms. (encyclopedia.com)
- The gymnosperms are those that also have roots and stem but lack the ovary and the stigma found on the angiosperms. (differencebetween.net)
- Gymnosperms have their seeds exposed unlike flowering plants, the angiosperms, which have their seeds enclosed in an ovary (i.e., fruit). (artplantaetoday.com)
- Pine trees are a familiar example of gymnosperms, a series of evolutionary lines of woody vascular seed plants that produce seeds not encased in an ovary. (blogspot.com)
- Gymnosperms bear stem and root system but do not bear ovary and stigma. (biologyeducare.com)
- Gymnosperms are a group of plants that produce seeds not enclosed within the ovary or fruit. (byjus.com)
- Basically, gymnosperms are plants in which the ovules are not enclosed within the ovary wall, unlike the angiosperms. (byjus.com)
- Spermatophytes encompass the angiosperms and the gymnosperms, whose seeds are not enclosed in an ovary. (biomedcentral.com)
- However, gymnosperm seeds arise directly on sporophylls (naked seeds) without covering from an ovary, unlike angiosperms. (pediaa.com)
- Gymnosperm is any plant, as members of the genus Pinus, in which the ovules are not enclosed in the ovary. (blogspot.com)
- The seeds of "gymnosperms" are borne exposed in open structures, such as cones or leaves. (washington.edu)
- Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo. (wikipedia.org)
- Gymnosperms are characterized by having naked seeds usually formed on open scales produced in cones. (jrank.org)
- Gymnosperm seeds develop either on the surface of scale- or leaf-like appendages of cones , or at the end of short stalks ( Ginkgo ). (wikipedia.org)
- Do all gymnosperms have cones? (artplantaetoday.com)
- Gymnosperms are seed plants that have evolved cones to carry their reproductive structures. (lumenlearning.com)
- Megaspores made in cones develop into the female gametophytes inside the ovules of gymnosperms, while pollen grains develop from cones that produce microspores. (lumenlearning.com)
- This term comes from the fact that the ovules and seeds of gymnosperms develop on the scales of cones rather than in enclosed chambers called ovaries. (lumenlearning.com)
- Like all seed plants, gymnosperms are heterosporous: both sexes of gametophytes develop from different types of spores produced by separate cones. (lumenlearning.com)
- The seeds of gymnosperms are naked and cone-bearing in nature which develops either on the cones or scale (leaf-like appendages). (biologyeducare.com)
- Gymnosperms are flowerless plants which create seeds and cones. (biologyeducare.com)
- Seeds of all gymnosperms are enclosed in cones for protecting their seeds. (biologyeducare.com)
- Gymnosperm seeds are found in unisexual cones. (diff.wiki)
- In gymnosperms, microsporophylls are connected together to form male cones (strobile), and megasporophylls are connected together to form female cones. (pediaa.com)
- Another un‐pine‐like gymnosperm is Ginkgo biloba , the maidenhair tree, the sole remaining representative of a group of important plants of the Mesozoic forests. (cliffsnotes.com)
- Several features unite Ginkgo with the rest of the gymnosperms, but to which precise lineage-the conifer line or the cycad-is still being debated. (cliffsnotes.com)
- Although the fossil record is virtually nonexistent, studies suggest that the Gnetales are a relatively young group that evolved from the angiosperms and thus are unrelated to the other gymnosperms. (encyclopedia.com)
- For example, morphological studies consistently identify the Gnetales as the extant sister group to angiosperms (the so-called "anthophyte" hypothesis), whereas a number of molecular studies recover gymnosperm monophyly, and few agree with the morphology-based placement of Gnetales. (pnas.org)
- A common theme of most morphological studies of seed plant phylogeny is that extant gymnosperms are not monophyletic, with the Gnetales ( Ephedra, Gnetum, and Welwitschia ) being the sister group of angiosperms ( 1 - 7 ). (pnas.org)
- Relationships among the five groups of extant seed plants, including the placement of the Gnetales and the related issue of gymnosperm monophyly, should therefore be regarded as unsettled. (pnas.org)
- Dating dispersal and radiation in the gymnosperm Gnetum (Gnetales)--clock calibration when outgroup relationships are uncertain. (semanticscholar.org)
- more Ephedra, Gnetum , and Welwitschia constitute the gymnosperm order Gnetales of still unclear phylogenetic relationships within seed plants. (klinika-trufanovoy.ru)
- Gnetum (Gnetales) species are suggested to be unique extant gymnosperms that have acquired high photosynthetic and transpiration capacities as well as greater xylem hydraulic capacity and efficiency compared with all other extant. (klinika-trufanovoy.ru)
- A far more rudimentary form of double fertilization occurs in the sexual reproduction of an order of gymnosperms commonly known as Gnetales. (rug.nl)
- citation needed] Most recent systems place the Welwitschiaceae in the gymnosperm order Gnetales. (wikipedia.org)
- The ancestors of the extant gymnosperm orders-Gnetales, Coniferales, Cycadales and Ginkgoales-arose during the Late Paleozoic, and became the dominant component of the Late Permian and Mesozoic flora. (wikipedia.org)
- Gymnosperms are heterosporous. (differencebetween.com)
- Gymnosperm plants are heterosporous. (toppr.com)
- Both angiosperm and gymnosperm plants are heterosporous, produce two types of spores as microspores and megaspores. (pediaa.com)
- We first downloaded from GenBank all core nucleotide sequence data from gymnosperms (Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta). (hindawi.com)
- Three living genera-none of whom resemble one another or any other living gymnosperm-constitute the Gnetophyta, Gnetum, Ephedra , and Welwitschia . (cliffsnotes.com)
- Perianth or calyx and corolla are absent in most of the gymnosperms but they are present in Gnetum . (biologyeducare.com)
- Vessels are absent (exception: Gnetum: the most advanced group in Gymnosperm). (plantlet.org)
- Archegonia are produced in the ovules of all Gymnosperms except Gnetum. (plantlet.org)
- These results on Gnetum ecophysiology indicate that the coupling of vessels, broad pinnate-veined leaves and the liana habit do not signal the evolution of a highly opportunistic, light-demanding life history in gymnosperms . (klinika-trufanovoy.ru)
- Compare how gymnosperm and angiosperm vascular seed plants store their seed Video presentation describing the differences in seed storage between angiosperms and gymnosperms. (britannica.com)
- To become stationary plants and still obtain the water they require gymnosperms use vascular tissues to transport water that is absorbed by their roots. (reference.com)
- The development of vascular tissues and roots enabled primitive gymnosperms to develop upright growth forms. (reference.com)
- Megaspores are structures that are part of the alternation of generations in many seedless vascular cryptogams , all gymnosperms and all angiosperms . (wikipedia.org)
- Angiosperms and gymnosperms are two major types of vascular plants (plants that have conducting tissue). (diff.wiki)
- T his gymnosperm stem shows a complete secondary growth because the increase in diameter caused by the vascular tissue growing has been followed by the formation of a relatively well-developed periderm. (uvigo.es)
- The xylem rays consist of uniseriate layers of parenchyma cells, typical of gymnosperms.The periodicity of the activity of the vascular cambium along the year generates the growth rings. (uvigo.es)
- Another class of Gymnosperms, Ginkgophyta, has only one living species. (byjus.com)
- The derivation of the word "gymnosperm" means naked seeds and is from the Greek words gymno meaning naked or bare and sperm meaning seed. (washington.edu)
- The term 'Gymnosperm' is originated from two Greek words, 'gymnos' meaning naked and 'sperma' meaning seed. (biologyeducare.com)
- In "gymnosperms", the sexes are separate, so both male and female sporangia are produced either on the same plant (monoecism) or on separate plants (dioecism). (washington.edu)
- The study of gymnosperms is essential in order to understand the evolutionary significance and diversity of the plant kingdom. (foyles.co.uk)
- An initial angiosperm-gymnosperm split implies a long stem lineage preceding the explosive Mesozoic radiation of flowering plants and suggests that angiosperm origins and homologies should be sought among extinct seed plant groups. (pnas.org)
- Here we have sampled two mitochondrial protein genes, cox 1 (cytochrome oxidase I) and atp A (= atp 1, ATPase I), from all extant seed plant lineages, including all widely recognized gymnosperm families. (pnas.org)
- Recent focus on plant-insect associations during the angiosperm radiation from the last 30 million years of the Early Cretaceous has inadvertently de-emphasized a similar but earlier diversification that occurred among gymnosperms. (si.edu)
- Two kinds of higher plants-the gymnosperms and angiosperms-have developed to become the dominant type of land plant. (blogspot.com)
- This discovery led to the recognition of the progymnosperms as a distinct plant group which completely altered biologists' view of gymnosperm evolution. (blogspot.com)
- Several issues need to be addressed regarding the evolution of the seed plant genome, and that of the plant genome predating the gymnosperm-angiosperm (GA) divergence. (biomedcentral.com)
- Evidence of plant-arthropod interactions in three orders of gymnosperms is documented in at least five localities from Lower Permian strata of the Río Genoa Formation (Patagonia, Argentina). (conicet.gov.ar)
- Thus, in most of the gymnosperm plants, the endosperm is produced as a haploid tissue. (differencebetween.net)
- 2. The angiosperms are those plants that have triploid tissues while the gymnosperms have haploid. (differencebetween.net)
- The life cycle of gymnosperms is both haploid and diploid, i.e., they reproduce through the alternation of generations. (byjus.com)
- Nevertheless, the genomes of some gymnosperms, such as in the conifer family Pinaceae, are among the largest of all known organisms [ 21 ], with haploid genome sizes up to 37 Gb for Pinus gerardiana [ 22 , 23 ]. (biomedcentral.com)
- Use this interactive Botany Quiz to test your knowledge of Botany and the fascinating botanical world of plants, algae, fungi, bryophytes and ferns, gymnosperms, and angiosperms. (zaneeducation.com)
- Let us have an overview of the characteristics, examples, classification and examples of gymnosperms. (byjus.com)
- In this article you will find the characteristics of algae, bryophytes, pteridophytes, gymnosperm and angiosperms. (indiastudychannel.com)
- Unlike bryophytes and pteridophytes, in gymnosperms, the male and the female gametophytes do not have an independent free-living existence. (bankofbiology.com)
- DNA C-values in land plants (comprising bryophytes, lycophytes, monilophytes, gymnosperms and angiosperms) vary approximately 1000-fold from approx. (nih.gov)
- Insights into the distribution of C-values in each group of land plants were gained by superimposing available C-value data (4119 angiosperms, 181 gymnosperms, 63 monilophytes, 4 lycophytes and 171 bryophytes) onto phylogenetic trees. (nih.gov)
- Histograms showing the distribution of DNA C-values for (A) 4119 angiosperms, (B) 181 gymnosperms, (C) 63 monilophytes, (D) 4 lycophytes, and (E) 171 bryophytes. (nih.gov)
- followed by the range of nuclear DNA C-values encountered in each group or family of (A) angiosperms, (B) gymnosperms, (C) monilophytes and lycophytes, and (D) bryophytes. (nih.gov)
- When fossil gymnosperms such as Bennettitales, Caytonia and the glossopterids are considered, it is clear that angiosperms are nested within a larger gymnosperm clade, although which group of gymnosperms is their closest relative remains unclear. (wikipedia.org)
- The first group of gymnosperms to appear was the progymnosperms. (blogspot.com)
- A likelihood-based analysis of the evolution of genome size in 165 gymnosperms finds evidence for heterogeneous rates of genome size evolution due to an elevated rate in Pinus . (hindawi.com)
- Many gymnosperms have exceptionally large genomes (e.g., [ 5 - 7 ]), and this has hindered whole-genome sequencing projects, especially among economically important Pinus species. (hindawi.com)
- Other studies have quantified patterns of genome size among gymnosperms, especially within Pinus and the other Pinaceae [ 6 , 7 , 11 - 14 ]. (hindawi.com)
- Fossil records indicate "gymnosperms" originated in the Paleozoic Era, during the middle Devonian Period about 390 million years ago, and reached their greatest diversity during the Mesozoic Era, between 60 to 225 million years ago. (washington.edu)
- Gymnosperm (Zamites gigas) fossil. (sciencephoto.com)
- The regeneration hypothesis for gymnosperm exclusion by angiosperms is consistent with several aspects of the fossil record such as the early disappearance of gymnosperms from early successional environments where competition with angiosperms would have been most severe. (deepdyve.com)
- The earliest fossil of gymnosperms is about 305 million-year-old. (pediaa.com)
- There is conflicting evidence on the question of whether the living gymnosperms form a clade. (wikipedia.org)
- Yet the other major clade of seed plants, the gymnosperms, have received far less attention, with few comprehensive studies of diversification and no sequenced genomes. (hindawi.com)
- As will be discussed in subsequent sections, the various environmental adaptations gymnosperms have represent a step on the path to the most successful (diversity-wise) clade (monophyletic branch). (lumenlearning.com)
- increases in Santalales and some monocots (both angiosperms), Pinaceae, Sciadopityaceae and Cephalotaxaceae (Gymnosperms) and possibly in the Psilotaceae + Ophioglossaceae clade (monilophytes). (nih.gov)
- The gymnosperms are divided into six phyla. (wikipedia.org)
- The gymnosperms are those plants who are mostly limited to woody trees. (differencebetween.net)
- Gymnosperms are all woody, perennial and usually have long reproductive cycles. (deepdyve.com)
- Gymnosperms are unisexual and are woody type trees which bear needle-like leaves to reduce water loss. (biologyeducare.com)
- Atomic force microscopy was used to compare the structures of dried, torus-bearing pit membranes from four woody species, three angiosperms and one gymnosperm. (usda.gov)
- Just like any other member of gymnosperms, Gnetophytes are also relics from the past. (byjus.com)
- Classification of gymnosperms now recognizes four extant divisions. (britannica.com)
- Many systems of classification of gymnosperms have been proposed by different authors. (plantlet.org)
- The resulting tree provides a starting point for large-scale evolutionary and ecological analyses of gymnosperms and will hopefully be a resource to promote and guide future phylogenetic and comparative studies. (hindawi.com)
- Gymnosperms are older than angiosperms on the evolutionary scale. (lumenlearning.com)
- Gymnosperms have an evolutionary significance and show some unique features. (toppr.com)
- Although there are over 260,000 species of angiosperms today compared to about 1,000 species of gymnosperms, the gymnosperms are just as important in the evolutionary history and diversity of the planet. (biologydictionary.net)
- Analyses with outgroups screened to avoid long branches consistently identify all gymnosperms as a monophyletic sister group to angiosperms. (pnas.org)
- In early classification schemes, the gymnosperms (Gymnospermae) were regarded as a "natural" group. (wikipedia.org)
- An internal fluid is required for fertilization in gymnosperms, and no water is necessary for fertilization in anthophytes. (differencebetween.com)
- Double fertilization doesn't take place in Gymnosperm. (plantlet.org)
- The more primitive process of double fertilization in gymnosperms results in two diploid nuclei enclosed in the same egg cell. (rug.nl)
- We assembled a phylogenetic supermatrix containing over 4.5 million nucleotides from 739 gymnosperm taxa. (hindawi.com)
- This study first synthesizes the available phylogenetically informative sequences to build a phylogenetic hypothesis of gymnosperms that reflects the recent advances in sequencing and computational phylogenetics. (hindawi.com)
- We constructed a phylogenetic hypothesis of gymnosperms from available, phylogenetically informative sequence data in GenBank that was available on June 30, 2009. (hindawi.com)
- Phylogenetic analyses of 157 gene families for which at least two duplicates were mapped on the spruce genome indicated that ancient gene duplicates shared by angiosperms and gymnosperms outnumbered conifer-specific duplicates by a ratio of eight to one. (biomedcentral.com)
- We use the tree to examine large-scale patterns of diversification of the extant gymnosperm lineages and also to examine rates of genome size evolution. (hindawi.com)
- The life cycle of "gymnosperms" depicts a dominant sporophyte and reduced gametophytes with the female gametophyte retained on the sporophyte (see illustration of conifer life cycle). (washington.edu)
- The nutritive tissue of "gymnosperm" seeds is derived from the female gametophyte. (washington.edu)
- An archigonium is present in gymnosperm female gametophyte and no archegonia in anthophyte female gametophyte. (differencebetween.com)
- The male gametophyte of gymnosperms and angiosperms. (sparknotes.com)
- The gymnosperms are those plants are generally cone-bearing in nature. (differencebetween.net)
- 3. The leaves of the angiosperms are flat while those of the gymnosperms are cone bearing or needle like. (differencebetween.net)
- It is important to note that the seeds of gymnosperms are not enclosed in their final state upon the cone. (lumenlearning.com)
- In gymnosperms, a male cone is present and instead, anthophytes possess a flower. (differencebetween.com)
- Strobilus or cone is the reproductive structure of gymnosperms. (toppr.com)
- Evidence has also been found that mid-Mesozoic gymnosperms were pollinated by Kalligrammatid lacewings, a now-extinct genus with members which (in an example of convergent evolution) resembled the modern butterflies that arose far later. (wikipedia.org)
- Most of the Gymnosperms became extinct in the Cenozoic era (from 65 million years ago to present day). (wikipedia.org)
- Leaves of the extinct jurassic cycad-like bennettitalean gymnosperm from Yorkshire, UK. (sciencephoto.com)
- You may navigate from the Gymnosperm Database Site Map All Taxa on the Gymnosperm Database . (equisetites.de)
- However, the gymnosperms are those plants who are considered to be unisexual in nature while the angiosperms are bisexual. (differencebetween.net)
- The stem of gymnosperms can be branched or unbranched. (byjus.com)
- Gymnosperms are the seed-producing plants, but unlike angiosperms, they produce seeds without fruits. (byjus.com)
- The microsporangia of gymnosperms develop in pairs toward the bases of the scales, which are therefore called microsporophylls . (wikipedia.org)
- Microsporophylls in gymnosperms are modified to stamens in anthophytes. (differencebetween.com)
- Yet compared to angiosperms, little is known about the patterns of diversification and genome evolution in gymnosperms. (hindawi.com)
- This large genome size is interesting because one suggested mechanism for rapid increases in genome size, polyploidy, is rare among gymnosperms [ 8 ]. (hindawi.com)
- These studies have largely focused on finding morphological, biogeographic, or life history correlates of genome size, but the rates and patterns of genome size evolution in gymnosperms are largely unknown. (hindawi.com)
- The biggest limitation in what we are doing is that there is no published gymnosperm genome," says Prior. (bio-medicine.org)
- While much light has been shed on the mechanisms and rate of genome evolution in flowering plants, such knowledge remains conspicuously meagre for the gymnosperms. (biomedcentral.com)
- Are ancient duplicates, those preceding the GA split, relatively more abundant and more translocated through the gymnosperm genome than most recent duplicates specific to the gymnosperms? (biomedcentral.com)
- Dr. Nixon and Bruce describe 115 species of gymnosperms growing in coniferous gymnosperm forests, gymnosperm foothill (pinyon-juniper) forests, and gymnosperm ( Ephedra ) shrubland. (artplantaetoday.com)
- The following figure shows the life cycle of a gymnosperm. (toppr.com)
- Special xylem tissue called "compression wood" is formed on the lower side of inclined stems when gymnosperms grow on a slope. (scirp.org)
- Unlike other gymnosperms , they possess vessel elements in the xylem. (klinika-trufanovoy.ru)
- Gymnosperms are heterosporus and bear different types of spores. (plantlet.org)
- In gymnosperms, seeds are not enclosed in a fruit (naked) and, therefore, ovules are directly borne on megasporophylls. (pediaa.com)
- They consist of two classes, the gymnosperms and the angiosperms . (ufl.edu)
- Megasporophylls of gymnosperms are modified to carpels in anthophytes. (differencebetween.com)
- These are the characteristic features of Gymnosperms and will be classified under the same. (toppr.com)
- Other gymnosperms have only a single conductive strandin their stems. (blogspot.com)
- Gymnosperms are "non-flowering" plants and come in the form of trees and shrubs, although there is one vine that is classified as a gymnosperm. (diff.wiki)
- The gymnosperms are evergreen trees and shrubs with xerophytic adaptations. (studyread.com)
- They are the most abundant trees within gymnosperms, both in terms of number of species and in number of samples. (botanical-online.com)
- Unlike many aquatic plants that float freely in the water column, terrestrial gymnosperms anchor themselves to a single spot for the duration of their lives. (reference.com)
- Scientists suggest that the end of the Permian period (251 million years ago) gymnosperms became the dominant plants in terrestrial ecosystems. (pediaa.com)
- Gymnosperms are xerophytic and terrestrial but never aquatic. (plantlet.org)
- The gymnosperms and angiosperms together compose the spermatophytes or seed plants. (wikipedia.org)
- The mature pollen grain (1 n ) is winged in many "gymnosperms", a feature that facilitates air transport. (washington.edu)
- Pine trees are the most often cited example of a gymnosperm. (artplantaetoday.com)
- In the Mesozoic era (251-65.5 million years ago), gymnosperms dominated the landscape. (openstax.org)
- Gymnosperms came into existence in the early Mesozoic era about 359 to 299 million years ago. (biologydictionary.net)