Fasciation (pronounced , from the Latin root meaning "band" or "stripe"), also known as cresting, is a relatively rare condition of abnormal growth in 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.
Some plants are grown and prized aesthetically for their development of fasciation.
Cause
Fasciation can be caused by hormonal imbalances in the
cells of plants, which are cells where growth can occur.
[Galun, Esra (2007). Plant Patterning: Structural and Molecular Genetic Aspects. World Scientific Publishing Company. p. 333. ] Fasciation can also be caused by random
Mutation.
Bacterial and viral infections can also cause fasciation.
The bacterial
Phytopathology Rhodococcus fascians has been demonstrated as one cause of fasciation, such as in sweet pea (
Lathyrus odoratus) plants,
and in lilies (Lilium longiflorum),
but many fasciated plants have tested negative for the bacteria in studies,
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.
Genetic fasciation is not contagious, but infectious 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.
Occurrence
Although fasciation is rare overall, it has been observed in over 100 vascular plant families,
including members of the
Genus Acer,
Aloe,
Acanthosicyos,
Cannabis,
Celosia,
Cycas,
Delphinium,
Digitalis,
Echinacea,
Echinopsis,
Euphorbia,
Forsythia,
Glycine max (specifically,
soybean plants),
,
Iochroma,
Prunus,
Salix, and many genera of the
cactus family,
Cactaceae. Cresting results in undulating folds instead of the typical "arms" found on mature
saguaro cactus.
)]] Many strawberry (Fragaria'' spp.) cultivars are susceptible to fasciation, often in response to environmental stresses.
Some varieties of Celosia are raised especially for their dependably fasciated flower heads, for which they are also called "cockscomb".
Prevention
Fasciation that is caused by bacteria can be controlled by not using fasciated plants and disposing of fasciated material.
Avoiding injury to plant bases and keeping them dry can reduce the spread of bacteria.
Avoidance of grafting fasciated plants and the pruning of fasciated matter can also reduce the spread of bacteria.
Examples
File:Fasciation on a coneflower.jpg|An example of fasciation, or "cresting," on a coneflower ( Echinacea).
File:Double Dandelion.jpg|Fasciation leading to two fully formed flower heads on a dandelion.
File:Annas dupliqué.JPG|Pineapple
File:Digitalis Fasciation detail stem.jpg|Fasciation on Digitalis. Note the larger thickened stem compared to the normal-sized flowering spike on the left.
File:Fasciated Flowering Cherry branch.JPG|Fasciation on a flowering Prunus ( Prunus) tree
File:PSM V42 D335 Asparagus fasciation.jpg|Asparagus ( Asparagus officinalis) fasciation. Note the flattened state of the stem. Image published 1893.
File:Fasciated Dandelion 01.JPG|Common dandelion displaying both regular (upper right) and fasciated (center) flowers.
File:Fasciated Lilac.JPG|Fasciation on a lilac shrub.
File:Fasciated California Bluebell (Phacelia campanularia).jpg|Fasciation on a Phacelia campanularia or California bluebell wildflower.
File:Echinopsis pachanoi (7996941451).jpg| Trichocereus pachanoi with crested growth
File:Fasciated Showy Daisy July 3 2016.jpg|Fasciated showy daisy ( Erigeron speciosus).
File:Fasciated Crookneck Squash.jpg|Fasciated Crookneck Squash
File:Dandelion Fascination.jpg|alt=Pictured is common dandelion with multiple fully formed flower heads and a notably wide stem joined in fascination.|Fasciation seen on common dandelion
File:Geranium palustre fasciation.jpg|alt=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
File:Fasciation in Odontonema tubaeforme inflorescence.jpg|alt=Fasciation in Odontonema tubaeforme (Bertol.) Kuntze inflorescence.|Fasciation in the inflorescence of a cultivated Odontonema tubaeforme plant.
File:Sedum sexangulare exhibiting fasciation.jpg|Fasciation exhibited on Sedum sexangulare.
File:Fasciated smiley-face zinnia.png|Fasciation on a Zinnia elegans that resembles a smiley face
See also
Further reading
External links
