Callus (botany)

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In botany, the designation callus (also callus, plural calli or calli; from Latin callus "hardened, thick skin, callus") is used for different terms.

Callus as wound tissue

The undifferentiated, parenchymatic cell complexes with undirected growth that can arise after an injury are called callus . The unwooded callus tissue lignifies and can close a wound. In woody plants, the callus arises from the cambium , in herbaceous plants from the parenchyma through hypertrophic growth of the uninjured marginal cells and subsequent intensive cell division.

Callus as a tissue culture

Nicotiana tabacum - Calli

In botany, callus is a complex of undifferentiated, totipotent cells that develop from a piece of tissue or a cell that was previously taken from a living plant. This piece of tissue is placed in an artificially created nutrient medium , which contains mineral salts and organic compounds such as sugar and plant hormones that make callus growth possible in the first place. These hormones are naturally found in coconut water , but are not as efficient in nature as with synthesized hormones. Since the cells of a callus arise through mitosis , they should not differ genetically. However, polyploid cells often develop in calluses. Aneuploidy and ring chromosome formation have even been reported. Herbs seem to be more susceptible than tree species v. a. Having conifers for a change in chromosome number through callus cultivation.

The callus is of great interest, especially in plant research, as it enables plant tissue to be grown without a living host. After a few weeks it is possible to detach parts of the callus tissue and to cultivate these further separately in order to obtain further tissue cultures.

By adding phytohormones , a differentiation of the cells and thus z. B. a living plant sprout arise.

Before regeneration into a fertile plant, the calli can be used as a transformation target. The biolistic transformation or the transformation with agrobacteria are primarily used here. Transformation with silicon carbide crystal needles is also possible .

Callus as a thickening on plant organs

Calluses or thickenings on leaves, flowers and other plant organs , for example on the lip of orchids , are also referred to as “callus”.

Individual evidence

  1. ^ Karl Ernst Georges : Comprehensive Latin-German concise dictionary. 8th, improved and increased edition, Hahnsche Buchhandlung, Hanover 1913–1918. 1918, accessed on September 5, 2017 (The word is masculine and obeys the o-declension , hence the plural in -i; however, the variant callum (neuter) is more common).
  2. ↑ Schütt, Schuck, Stimm: Lexicon of tree and shrub species . Nikol, Hamburg 2002, ISBN 3-933203-53-8 , pp. 243 .
  3. ↑ CL Armstrong, J. Romero-Severson, TK Hodges: Improved tissue culture response of an elite maize inbred through backcross breeding, and identification of chromosomal regions important for regeneration by RFLP analysis . In: Theoretical and Applied Genetics . tape 84 , no. 5-6 , August 1992, ISSN  0040-5752 , pp. 755-762 , doi : 10.1007 / BF00224181 .
  4. ↑ Green, CE, Phillips, RL: Plant Regeneration from Tissue Cultures of Maize . In: Crop Science . tape 15 , no. 3 , January 6, 1975, p. 417-421 , doi : 10.2135 / cropsci1975.0011183X001500030040x .
  5. ↑ Bronwyn R. Frame, Hongyi Zhang, Suzy M. Cocciolone, Lyudmila V. Sidorenko, Charles R. Dietrich, Sue Ellen Pegg, Shifu Zhen, Patrick S. Schnable, Kan Wang: Production of transgenic maize from bombarded type II callus: Effect of gold particle size and callus morphology on transformation efficiency . In: In Vitro Cellular & Developmental Biology - Plant . tape 36 , no. 1 , January 2000, ISSN  1054-5476 , pp. 21-29 , doi : 10.1007 / s11627-000-0007-5 .
  6. ↑ R. Brettschneider, D. Becker, H. Lörz: Efficient transformation of scutellar tissue of immature maize embryos . In: Theoretical and Applied Genetics . tape 94 , no. 6-7 , June 1997, ISSN  0040-5752 , pp. 737-748 , doi : 10.1007 / s001220050473 .
  7. ↑ BR Frame, H. Shou, RK Chikwamba, Z. Zhang, C. Xiang, TM Fonger, SE Pegg, B. Li, DS Nettleton, D. Pei, K. Wang: Agrobacterium tumefaciens-Mediated Transformation of Maize Embryos Using a Standard binary vector system . In: Plant Physiology . tape 129 , no. 1 , May 2002, ISSN  0032-0889 , p. 13-22 , PMC 1540222 (free full text).
  8. ↑ Vladimir Sidorov, Larry Gilbertson, Prince Addae, David Duncan: Agrobacterium-mediated transformation of seedling-derived maize callus . In: Plant Cell Reports . tape 25 , no. 4 , April 2006, ISSN  0721-7714 , p. 320-328 , doi : 10.1007 / s00299-005-0058-5 , PMID 16252091 .
  9. ↑ Yukoh Hiei, Shozo Ohta, Toshihiko Komari, Takashi Kumashiro: Efficient transformation of rice (Oryza sativa L.) mediated by Agrobacterium and sequence analysis of the boundaries of the T-DNA . In: The Plant Journal . tape 6 , no. 2 , August 1994, ISSN  1365-313X , p. 271-282 , doi : 10.1046 / j.1365-313X.1994.6020271.x .
  10. ↑ Yuji Ishida, Yukoh Hiei, Toshihiko Komari: Agrobacterium-mediated transformation of maize . In: Nature Protocols . tape 2 , no. 7 July 2007, ISSN  1754-2189 , pp. 1614-1621 , doi : 10.1038 / nprot.2007.241 .
  11. ↑ Y. Ishida, H. Saito, S. Ohta, Y. Hiei, T. Komari, T. Kumashiro: High efficiency transformation of maize (Zea mays L.) mediated by Agrobacterium tumefaciens . In: Nature Biotechnology . tape 14 , no. June 6 , 1996, ISSN  1087-0156 , pp. 745-750 , doi : 10.1038 / nbt0696-745 , PMID 9630983 .
  12. ↑ Sonia Tingay, David McElroy, Roger Kalla, Sarah Fieg, Mingbo Wang, Sarah Thornton, Richard Brettell: Agrobacterium tumefaciens-mediated barley transformation . In: The Plant Journal . tape 11 , no. December 6 , 1997, ISSN  1365-313X , pp. 1369-1376 , doi : 10.1046 / j.1365-313X.1997.11061369.x ( wiley.com [PDF]).
  13. ^ Bronwyn R. Frame, Paul R. Drayton, Susan V. Bagnall, Carol J. Lewnau, W. Paul Bullock, H. Martin Wilson, James M. Dunwell, John A. Thompson, Kan Wang: Production of fertile transgenic maize plants by silicon carbide whisker-mediated transformation . In: The Plant Journal . tape 6 , no. 6 , December 1994, ISSN  1365-313X , pp. 941-948 , doi : 10.1046 / j.1365-313X.1994.6060941.x .
  14. ^ Gerhard Wagenitz : Dictionary of Botany. Morphology, anatomy, taxonomy, evolution. 2nd, expanded edition. Nikol, Hamburg 2008, ISBN 978-3-937872-94-0 .

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