In botany and seed growing, the term stratification (from Latin stratum, layer) the cold treatment of seeds to stimulate their germination in a buffered environment. As buffers are used substrate layers, which stabilize the water content, temperature, and the light terminal physically and reduce inevitable in free wet storage infestation with microorganisms.
Almost all seeds undergo during and immediately after their maturity on the mother plant dormancy or dormancy that must be overcome before germination can take place. This initially serves already to prevent the germination of the mother plant. In addition, often, certain environmental conditions be met before the seeds can germinate. Numerous types of seeds need a cold period before dormancy is overcome. Characterized the germination of seeds in the unfavorable time before onset of winter is prevented. If seeds exposed to artificially these conditions, it is called stratification.
The term vernalization refers to the induction of Blühvorgangs by a cold period. This can as well as the stratification of plants take place already in the seed stage.
Stratification in the woods propagation
Hard -shelled seeds of woody species is pre-treated by special storage conditions over several weeks or months, so that it runs fairly simultaneously in the seedbed, that is, become a seedling. Cores, for example, peaches, cherries, plums, etc. are added alternately with wet gravel layers (about nuclear high) in a container ( barrel, wooden tub ) in late autumn. So they keep in a cool but frost-free for several months until the end of winter. During this time, the hard shell swells and opens. The seed falls into the same germ mood. In March / April the pretreated by stratification cores are applied in a suitably prepared seedbed.
The following standard works treat the subject comprehensively stratification for all in Central Europe increased woody plants:
- Andreas Bärtels: woody plant propagation, Ulmer: Stuttgart. ISBN 3800151863
- MacCarthaigh Donnchadh (ed. ), Wolfgang Speth man (ed.): Kruss 's woody proliferation, Ulmer: Stuttgart, 2003 ( to 2003 Paul Parey Verlag ). ISBN 3800145472
The origin of the term stratification ( stratification of seeds ) from the forest practice explain older works particularly well (example):
- Hubert judder The forest nursery, Bavarian Agriculture Publisher: Munich 1952 ( no ISBN )
An example of today's stratification method:
- Andreas Ludwig, Bavarian State Institute of Forestry: stratification of beech seed (PDF file, 109 kB)
The ( university ) Biology demonstrates their freshmen the breaking of dormancy in the biotechnical stratification. However, a study of the underlying biochemistry is missing: