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Encyclopedia > Spine (biology)
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Raised thorns on the stem of the wait-a-bit climber
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Thorns on rose stems

A spine is a rigid, pointed surface protuberance or needle-like structure on an animal, shell, or plant, presumably serving as a defense against attack by predators. For examples: the quills of a porcupine, the needles of a cactus, or the thorns of a shrub like the rose are all spines. Although spines generally serve as a passive defense mechanism, in some species they can be hollow and contain poisonous substances that cause lasting pain or even paralysis. Download high resolution version (500x667, 89 KB)Close up of Caesalpinia decapetala stem showing spines and lenticels. ... Download high resolution version (500x667, 89 KB)Close up of Caesalpinia decapetala stem showing spines and lenticels. ... Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Species About 100, see text References:   U. of Illinois 2002-05-29 A rose is a flowering shrub of the genus Rosa and the flower of this shrub. ... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Bilateria  Acoelomorpha  Orthonectida  Rhombozoa  Myxozoa  Superphylum Deuterostomia     Chordata (vertebrates, etc. ... The hard, rigid outer calcium carbonate covering of certain animals is called a shell. ... Divisions Green algae Land plants (embryophytes) Non-vascular embryophytes Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Seedless vascular plants Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants... Genera Family Erethizontidae   Coendou   Sphiggurus   Erethizon   Echinoprocta Family Hystricidae   Atherurus   Hystrix   Thecurus   Trichys The porcupine is a rodent known for its coat of sharp spines, or quills that defend it from predators. ... Genera Many, see text A cactus (plural, cacti or cactuses) is a type of (usually) succulent plant belonging to the dicotyledonous flowering plant family, Cactaceae. ... A willow shrub A shrub or bush is a horticultural rather than strictly botanical category of woody plant, distinguished from a tree by its multiple stems and lower height, usually less than 6 m tall. ... Species About 100, see text References:   U. of Illinois 2002-05-29 A rose is a flowering shrub of the genus Rosa and the flower of this shrub. ... The skull and crossbones symbol traditionally used to label a poisonous substance. ... According to the International Society for the Study of Pain, there are two different terms: pain and nociception. ... Paralysis is the complete loss of muscle function for one or more muscle groups. ...


Plant spines and thorns

Botanists use several terms somewhat loosely when referring to spine- or needle-like structures on plants; however, the following differences are sometimes distinguished:

  • prickle – a sharp outgrowth from the epidermis, also called an emergence and usually involving some subdermal tissue as well; see also hair.
  • spine – a modified stipule or sharp branchlet found in a leaf axile or on the margin of a leaf.
  • thorn – Sharp outgrowth from a stem other than at a node. Modified stem.

"Thorns", most notably those on roses, are common literary symbols for the hidden dangers or woes of something beautiful or pleasant. Roses lack true thorns since their prickles emerge from the epidermis rather that the pericycle. Growth from the pericycle would make it a modifided stem and therefore a thorn. Some roses have been bred not to have prickles. Epidermis could refer to: In plants, the outermost layer of cells covering the leaves and young parts of a plant, see plant dermal tissue system. ... Interior structure of a trichome. ... In botany, a leaf is an above-ground plant organ specialized for photosynthesis. ... In botany, a leaf is an above-ground plant organ specialized for photosynthesis. ... A stem is the above ground axis of a vascular plant. ...


See also

SETA (Seksuaalinen Tasavertaisuus RY, Sexual Equality), the main gay and lesbian rights organisation in Finland. ...

References

  • Esau, K. 1965. Plant Anatomy, 2nd Edition. John Wiley & Sons. 767 pp.
  • Llamas, K. A. 2003. Tropical Flowering Plants. Timber Press, Portland. 423 pp.

  Results from FactBites:
 
SPINE :: Home (0 words)
Structural Proteomics In Europe (SPINE) is an integrated research project which brings together some of the top European structural biology institutions in an unprecedented collaborative effort to develop new methods and technologies for high-throughput structural biology.
SPINE is funded within Framework V of the European Commission for three years from 1 October 2002 and co-ordinated by Professor Dave Stuart, Division of Structural Biology, University of Oxford.
The project is funded by the European Commission as the SPINE, contract-no. QLG2-CT-2002-00988 under the RTD programme "Quality of Life and Management of Living Resources".
Cactus Spines (1310 words)
To be truly leaf-like, spine primordia should occur at the points of intersection of two sets of Fibonacci spirals centered on the axillary bud apical meristem just as ordinary leaves occur at the intersection points of spirals centered on the shoot apical meristem.
The benefit of such spines definitely appears to be blocking sunlight and thus preventing the plant from over heating, the chlorophyll from being bleached and the plant's DNA from being damaged.
In other species, the spines are flat, thin and papery, being too flexible to deter animals, but broad enough to shade the plant (as well as to camouflage the cacti among the grasses with which it grows).
  More results at FactBites »


 

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