Fasciation

Fasciation or Fasziation is a generally rare and unusual growth form of plants. The plants or plant parts affected are usually called comb shapes or cristates. Associations changes have been observed at more than one hundred different plant species. They can occur on all plant parts such as roots, stem axis, leaves, inflorescences, flowers and fruits of both herbaceous and woody plants.

Fasciation has a great similarity with a dichotomous branching, in which share the apical cells of a shoot in two fork rung. In the fasciation, however, the division process remains incomplete, so that the otherwise punctate growing tip of the shoot tip, widened linear. Thereby, the following tissue will not as normally cylindrical, but strip-or ridge -shaped and formed as a result of internal stresses often twisted.

Possible triggers a fasciation are damage caused by viruses and phytopathogenic bacteria ( Rhodococcus fascians ), especially by those in the plants spent plasmids, fungal infections, mites, chemicals, ionizing radiation and spontaneous mutation. Probably call the damage caused by the growth disorders in plants, a genetic Alternativprogamm on which switches from the normal in seed plants branching through lateral buds on the original dichotomous branching. Can this but lost, for example due to the course of evolution or previous umfunktionierter genes do not run to completion, it comes to fasciation.

Quite often Cristatformen are such as observed in highly succulent and only slightly branched plants cacti. They occur naturally and seem like a very large and old specimens show not to hinder the affected plants. In culture, however, they are often grafted to improve the conservation and Vermehrbarkeit. Sometimes develop from cristates spontaneously returned to normal rung. In herbaceous plants or dünntriebigen sometimes result from the fasciation supply problems, so that the cristates back dry after some time. With a variety of the silver fire tuft ( Celosia argentea var cristata ) is the ability to form verbänderter inflorescences hereditary and is obtained by breeding work.

Also occur in inflorescences of dandelions associations conclusions on unusually frequent. This case, both verbänderte inflorescence, as well as several inflorescences normal form occur at the tip of a fasciated stem axis.