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).
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.
A plant division of GYMNOSPERMS consisting of cone-bearing trees and shrubs.
A plant family of the order Pinales, class Pinopsida, division Coniferophyta, known for the various conifers.
A plant species of the genus PINUS which is the subject of genetic study.
A plant family of the order Cycadales, class Cycadopsida, division CYCADOPHYTA.
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).
The functional hereditary units of PLANTS.
The element in plants that contains the female GAMETOPHYTES.
A layer of living cells between the bark and hardwood that each year produces additional wood and bark cells, forming concentric growth rings.
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)
Deoxyribonucleic acid that makes up the genetic material of 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.
The genetic complement of a plant (PLANTS) as represented in its DNA.
A division of the plant kingdom. Bryophyta contains the subdivision, Musci, which contains the classes: Andreaeopsida, BRYOPSIDA, and SPHAGNOPSIDA.
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.
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.
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.
Remains, impressions, or traces of animals or plants of past geological times which have been preserved in the earth's crust.
A plant genus of the family TAXODIACEAE. Its POLLEN is one of the major ALLERGENS.
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.
The various physical methods which include wind, insects, animals, tension, and water, by which a plant scatters its seeds away from the parent plant.
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.
Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.
Expressed Sequence Tags
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)
The fertilizing element of plants that contains the male GAMETOPHYTES.