Offshoot (plant)

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Offshoots are a form of vegetative reproduction of plants in horticulture and forestry.

description

The formation of offshoots is a vegetative method of propagation in which the roots take place while the newly formed daughter plant is still connected to the mother plant. For this purpose, existing shoots of the mother plant are mechanically pressed down and hooked into a shallow groove in the ground. Resting buds (“eyes”) located at the nodes of the shoot sprout and form a new shoot that takes root when it comes into contact with the ground. As a support, the prostrate shoot is often covered flat with earth or piled up after it has sprouted. After the new shoots are rooted, the shoot that establishes the connection to the mother plant can be cut, the offshoot forms a new, independent individual (here ramet called).

Offshoots are very similar to subsidence , especially in the propagation of trees, both terms are also used synonymously. As far as the terms are differentiated, the differentiating difference is that when lowering the shoots are not pressed down over their entire length, but in an arc.

use

Cuttings and subsoil are a horticultural method of plant propagation, but they are based on the natural abilities of the species treated in this way and therefore cannot be carried out for all species. They have been known in horticultural practice since ancient times and are continued to this day in an almost unchanged form compared to previous centuries. The advantage of this method is that vegetative propagation can also be carried out in species that are difficult to take root and are therefore difficult to propagate as cuttings . The disadvantage is that the process is labor-intensive and difficult to mechanize and can be standardized on an industrial scale. It is therefore more common in the cultivation of ornamental plants and in house gardens and allotment gardens.

Offshoots as vegetative reproduction

Naturally occurring offshoots are a form of vegetative diaspores , so they are based on asexual reproduction. Since they are the result of purely vegetative reproduction, daughter plants created as offshoots are genetically identical to the mother plant, i.e. a clone of this. In fact, the concept of the clone was originally introduced for these vegetative reproductive processes such as offshoots and was only later transferred to genetic engineering methods.

The term “offshoot” is rarely used for natural forms of vegetative reproduction ( blastochory ). One definition would be that an offshoot is a side shoot that crawls above ground and is used for vegetative reproduction, which does not take root at the nodes between mother and daughter plants and usually only produces scale leaves , while (real) runners or stolons are stolons covered with leaves . As long as the connecting stem axis has not yet died, the (genetically identical, clonal) daughter plants are sometimes called “divides” because they only have limited individuality . Examples would be the aerial creeping shoots of the garden strawberry Fragaria x ananassa and the creeping buttercup Ranunculus repens . If this definition is followed, propagation via Kindel , i.e. complete small daughter plants at the tip of long side shoots, such as the green lily ( Chlorophytum comosum ) known as a houseplant, is one of the offshoots.

Naturally occurring propagation, corresponding to horticultural offshoots, in which normal shoots take root at the end of arch or long shoots with secondary contact with the ground and thus form extensive thickets, which become independent plant individuals after the connection is severed, occasionally occurs. An example would be the rust-leaved alpine rose ( Rhododendron ferrugineum ). Other forms of vegetative propagation, for example via brood onions or root tubers, do not belong here, even if the use of language is vague when the term is used in a non-technical way.

Individual evidence

  1. ↑ Wolfgang Kawollek: encyclopedia of horticulture. Eugen Ulmer Verlag, Stuttgart 2007, ISBN 978-3-8001-4886-8 , p. 9: Offshoot.
  2. ^ SR Mishra: Plant Reproduction. Discovery, New Delhi 2005, ISBN 81-7141-955-0 , pp. 27 ff., Chapter 3: Propagation by Layering.
  3. ↑ Cuttings, cuttings, cuttings - vegetative plant propagation. Leaflet of the Bavarian State Association for Horticulture and Land Care eV (www.gartenbauvereine.org)
  4. ↑ Andreas Roloff: Trees: Lexicon of practical tree biology. 2nd Edition. Wiley-VCH, 2012, ISBN 978-3-527-66119-0 , p. 2: Absenkerbewurzelung.
  5. ↑ Andreas Bärtels: Wood multiplication. Sowing, grafting, cuttings, cuttings. 5th edition. Eugen Ulmer Verlag, Stuttgart 2008, ISBN 978-3-8001-5186-8 , p. 52.
  6. ↑ Wolfgang Kawollek: encyclopedia of horticulture. Eugen Ulmer Verlag, Stuttgart 2007, ISBN 978-3-8001-4886-8 , p. 12: Absenker.
  7. ^ John E. Preece: A Century of Progress with Vegetative Plant Propagation. In: HortScience. 38 (5), 2003, pp. 1015-1025.
  8. ↑ What is cloning in agriculture? Federal Information Center for Agriculture, 2019.
  9. ^ Roman Marek: The clone and its pictures - About fascination and aesthetics in the history of concepts. In: Forum Interdisciplinary Conceptual History. E-Journal 1 (2), 2012, p. 17.
  10. ^ Anselm Krumbiegel: Morphology of the vegetative organs (except leaves). In: Series of publications for vegetation science. 38, 2002, pp. 93-118.
  11. ^ Adrian D. Bell: Illustrated morphology of flowering plants. Eugen Ulmer Verlag, Stuttgart 1994, ISBN 3-8001-2682-6 , p. 134: Morphology of the stem axis: offshoot. and p. 170: Vegetative propagation. (Original: Plant Form. An illustrated Guide to Flowering Plant Morphology. Oxford University Press, 1991)