Lowerers

The term “ sinker” is the term used to describe the shoots of plants that come into permanent contact with a suitable substrate at some distance from the roots of the plant and form roots at this contact point, which can create an independent, but genetically identical plant. The formation of independent plants from subsidence is a form of vegetative reproduction . The physiological separation between the sinker and the mother plant is not mandatory, but it occurs frequently. After the physiological interruption of the connection, the connection itself usually dies. Physically, the connection can still exist for a longer period of time, depending on its nature and the ambient conditions. The prerequisite for the formation of subsidence is the ability of the plant to blastochoria and the growth-related possibility that shoots can come into permanent contact with a suitable substrate. In contrast to Kindeln and brood buds , sinkers are not parts of plants specially formed for vegetative propagation. Cuttings are parts of plants that can form an independent plant without being bound to their mother plant.

Subsidence formation in nature

Many herbaceous plants and subshrubs , the shoots of which grow horizontally rather than vertically, form depressions under appropriate environmental conditions and thus often form dense stands. Plants whose shoots grow more vertically cannot easily form subsidence. One possibility for this is that when the rungs exceed a certain length, their own weight pushes them back towards the ground and finally touches it. Various tree species survive with this technology at the limits of their distribution areas, where generative reproduction is only less successful.

Another possibility, which occurs particularly with trees, is that a branch breaks through the action of external forces and thereby sinks to the ground, whereby the supply from the mother tree is not completely interrupted. Even after the physiological separation of the completely self-sustaining subsurface from the mother tree, the physical connection between the mother tree and subsoiler often remains in place for years or decades.

Lowering education by humans

Lowerers (left) of a tree

Young shoots of plants that are basically capable of forming subsidence are mostly used for the formation of subsidence for vegetative propagation ( Marcottage ). The shoot is bent into a groove in the earth and fixed there. Then it is covered with earth so that the end of the sprout looks out. After the rooting, the shoot is separated from the mother plant, creating a second, independent plant. The method is suitable when only a few young plants are to be produced. The basic requirement for the method is either the rung running close to the ground or sufficient flexibility of the rung. Shrubs whose shoots cannot be bent to the ground can be propagated by piling up. A heap of earth is poured around the rung, which is secured against slipping and drying out. The shoot forms new roots in the damp mound of earth. After a few weeks, the rooted shoot is cut off and planted separately. With this type of propagation, the mother plant is inevitably placed on the stick, which is usually not a problem with shrubs.

The offshoot process is a similar type of propagation . Here, a young sprout is placed in a gutter over a greater length and fixed. Over time, new shoots form on the top of the dropped shoot. The earth gutter is filled with earth either immediately after the shoot has been laid or only after the new shoot has formed. After filling with soil, roots form at the base of each new shoot. After rooting has taken place, the new shoots are cut off individually, creating independent plants. This method is suitable for producing a large number of young plants. Long and flexible bars are required for this method. It is important that the rung is fixed horizontally, otherwise new rungs would arise especially at the highest point (law of upper side conveyance).

In the case of plants that do not pass on certain properties, subsidence or offshoot formation is often the only way of propagation in plant breeding .

In the past, sinkers were used to create impenetrable hedges for border reinforcement, so-called kinks (also: Gebücke ), by z. B. European beech or hornbeam by bending down ("stooping") the branches were forced to form subsidence. This stabilized the weir hedges of the medieval land forces . Thorn bushes such as blackthorn , hawthorn and dog rose made it more difficult to overcome the weir hedges.

See also

• Stolo - a similar phenomenon

Individual evidence

1. ↑ Fritz Köhlein : Plants multiply made easy. Eugen Ulmer, Stuttgart, 1972, ISBN 3-8001-6052-8 .