Elongation growth
The elongation growth is the increase in the length of plant organs, which is not based on a proliferation, but on an elongation of cells .
The affected cells stretch by plastically stretching the cell wall while absorbing water into the vacuoles . The absorption of water is triggered by an accumulation of osmotically active substances such as potassium and malic acid in the vacuoles. The resulting turgor leads to a stretching of the cell wall, which is promoted at the same time by acidification and by the excretion of enzymes from the cell. The direction of stretching is determined by the orientation of the non-stretchable cellulose fibers in the cell wall, i.e. it is perpendicular to the preferred orientation of the fibers.
Examples of growth based solely on cell elongation are the budding of many trees in spring, the rapid elongation of the shoot in bamboo (58 cm per day) and the elongation of the seta (stem of the spore capsule) in mosses . Usually, however, the elongation growth follows the division growth ( cell division ) and the plasma growth (increase in the cytoplasm after the last cell division) as the last phase (see plant growth ).
literature
- Lexicon of biology : elongation growth . Spectrum, Heidelberg 1999.
Individual evidence
- ^ Joachim W. Kadereit, Christian Körner, Benedikt Kost, Uwe Sonnewald: Strasburger Textbook of Plant Sciences . Springer Spectrum, Berlin / Heidelberg 2014, p. 264.