Fasciation

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or mule's ear wildflower (on right) showing fasciation
A "crested" saguaro cactus (Carnegiea gigantea), resulting from fasciation, located at Saguaro National Park (West), Arizona, U.S.

Fasciation (pronounced /ˌfæʃiˈeɪʃən/, from the Latin root meaning "band" or "stripe"), also known as cresting, is a relatively rare condition of abnormal growth in vascular plants in which the apical meristem (growing tip), which normally is concentrated around a single point and produces approximately cylindrical tissue, instead becomes elongated perpendicularly to the direction of growth, thus producing flattened, ribbon-like, crested (or "cristate"), or elaborately contorted tissue.[1] Fasciation may also cause plant parts to increase in weight and volume in some instances.[2] The phenomenon may occur in the stem, root, fruit, or flower head.

Some plants are grown and prized aesthetically for their development of fasciation.[3] Any occurrence of fasciation has several possible causes, including hormonal, genetic, bacterial, fungal, viral and environmental causes.

Causation[]

Fasciation can be caused by hormonal imbalances in the meristematic cells of plants, which are cells where growth can occur.[4][5] Fasciation can also be caused by random genetic mutation.[6] Bacterial and viral infections can also cause fasciation.[4] The bacterial phytopathogen Rhodococcus fascians has been demonstrated as one cause of fasciation, such as in sweet pea (Lathyrus odoratus) plants,[7] but many fasciated plants have tested negative for the bacteria in studies,[8] hence bacterial infection is not an exclusive causation.

Additional environmental factors that can cause fasciation include fungi, mite or insect attack and exposure to chemicals.[8] General damage to a plant's growing tip[8] and exposure to cold and frost can also cause fasciation.[4][6] Some plants, such as peas and cockscomb Celosia, may inherit the trait.[8]

Fasciation is not contagious,[4] but bacteria that cause fasciation can be spread from infected plants to others from contact with wounds on infected plants and from water that carries the bacteria to other plants.[9]

Occurrence[]

Although fasciation is rare overall, it has been observed in over 100 vascular plant families,[10] including members of the genera Acer, Aloe, Acanthosicyos, Cannabis, Celosia, Cycas, Delphinium, Digitalis, Echinacea, Euphorbia, Forsythia, Glycine max (specifically, soybean plants),[11] Primula, Iochroma, Prunus, Salix,and many genera of the cactus family, Cactaceae.[citation needed] Cresting results in undulating folds instead of the typical "arms" found on mature saguaro cactus.[12]

Some varieties of Celosia are raised especially for their dependably fasciated flower heads, for which they are called "cockscomb".[4] The Japanese fantail willow (Salix sachalinensis 'Sekka') is another plant that is valued for its fasciations.[4][8]

Prevention[]

Fasciation that is caused by damage to genetic material and by bacteria can be controlled by not using fasciated plants and disposing of fasciated plants.[9] Avoiding injury to plant bases and keeping them dry can reduce the spread of bacteria.[9] Avoidance of grafting fasciated plants and the pruning of fasciated matter can also reduce the spread of bacteria.[9]

Examples[]

  • Fasciation

  • An example of fasciation, or "cresting," on a coneflower (Echinacea).

  • Fasciation leading to two fully formed flower heads on a dandelion.

  • Fasciation on Digitalis. Note the larger thickened stem compared to the normal-sized flowering spike on the left.

  • Fasciation on a flowering cherry (Prunus) tree

  • Asparagus (Asparagus officinalis) fasciation. Note the flattened state of the stem. Image published 1893.

  • Common dandelion displaying both regular (upper right) and fasciated (center) flowers.

  • Fasciation on a lilac shrub.

  • Fasciation on a Phacelia campanularia or California bluebell wildflower.

  • Fasciated showy daisy (Erigeron speciosus).

  • Fasciated Crookneck Squash

  • Pictured is common dandelion with multiple fully formed flower heads and a notably wide stem joined in fascination.

    Fasciation seen on common dandelion

  • Picture showing a regular flower of Geranium palustre on the left, and a fasciated one with a double amount of petals and two pistils.

    Regular (left) and fasciated (right) geranium flowers

See also[]

References[]

  1. ^ White, Orland E. (1948). "Fasciation". The Botanical Review. 14 (6): 319–358. doi:10.1007/BF02861723.
  2. ^ Albertsen, Marc C.; Curry, Therese M.; Palmer, Reid G.; Lamotte, Clifford E. (1983). "Genetics and Comparative Growth Morphology of Fasciation in Soybeans (Glycine max [L.] Merr.)". Botanical Gazette. 144 (2): 263–275. doi:10.1086/337372. JSTOR 2474652. S2CID 84260097.
  3. ^ Morris, Scott. "Fasciation in Flowers – What You Need To Know". Gardentoolbox. Archived from the original on 10 January 2014. Retrieved 10 January 2014.
  4. ^ Jump up to: a b c d e f Lerner, B. Rosie (September 2007). "Fascinating Fasciation". Purdue University Extension. Retrieved July 3, 2012.[permanent dead link]
  5. ^ Galun, Esra (2007). Plant Patterning: Structural and Molecular Genetic Aspects. World Scientific Publishing Company. p. 333. ISBN 9789812704085
  6. ^ Jump up to: a b "Fasciation in Vegetables and Fruits". University of Delaware Cooperative Extension. May 27, 2011. Archived from the original on February 7, 2015. Retrieved July 6, 2012.
  7. ^ Tilford, P.E. (1936). "Fasciation of Sweet Peas caused by Phytomonas fascians n.sp". Journal of Agricultural Research. 53 (5): 383–394. Retrieved July 7, 2012.
  8. ^ Jump up to: a b c d e Swift, Curtis E. (April 12, 1999). "Fasciation: Fascinating distortions of the plant world". Colorado State University Extension. Archived from the original on June 30, 2012. Retrieved July 3, 2012.[better source needed]
  9. ^ Jump up to: a b c d "Pests in Gardens and Landscapes". Statewide Integrated Pest Management Program, Agriculture and Natural Resources, University of California. October 13, 2008. Retrieved July 3, 2012.
  10. ^ Tang, Yuhong; Knap, Halina T. (1998). "Fasciation Mutation Enhances Meristematic Activity and Alters Pattern Formation in Soybean". International Journal of Plant Sciences. 159 (2): 249–260. doi:10.1086/297546. ISSN 1058-5893. JSTOR 2475089. S2CID 83559228.[better source needed]
  11. ^ Yamamoto, Etsuo; et al. (April 25, 2000). "Molecular characterization of two soybean homologs of Arabidopsis thaliana CLAVATA1 from the wild type and fasciation mutant". Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression. 1491 (1–3): 333–340. doi:10.1016/S0167-4781(00)00061-0. PMID 10760600.
  12. ^ "Campus Arboretum". University of Arizona. 2008-08-20. Archived from the original on 2010-01-06. Retrieved 2010-01-14.

Further reading[]

External links[]

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