Collenchyma

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Edge collenchyme in the stem axis cross-section of real celery , ( Apium graveolens L.), - The name corner collenchyme comes from the fact that in such a two-dimensional view the thickenings appear to be in the corners, whereas in the tissue it is actually edges.

The collenchyma is one of the strengthening tissues of plants . The word is derived from the Greek kolla = glue and enchyma = that which is poured in.

A distinction is made between the collenchyme and the sclerenchyme , whereby the collenchyme, as a non- lignified firming tissue that is still capable of growth and expansion, consists of living cells, whereas the sclerenchyme consists of dead cells. The living, usually prosenchymatic , but also partially isodiametric cells of the collenchyma often contain chloroplasts when they are on the periphery of organs, the cell walls are reinforced by cellulose or pectin deposits . The plasmodesmata, which can only be seen under an electron microscope, are plasmatic connections between the cytoplasm of neighboring cells that penetrate the middle lamella and the cell wall . The recesses that are located between the secondary walls of the cell wall are called pits .

Collenchyme is preferably located in parts of plants that are still growing, such as. B. in petioles and stems. If the tissues are older, the collenchyma can die and develop into sclerenchymal cells.

There are four different types of collenchyma:

• "Simple" collenchyma (more or less uniform cell wall thickening)
• Corner / edge collenchyma (strong cell wall thickening on the edges of the cells that meet, less or hardly any thickening on the surfaces)
• Plate collenchyma (strong thickening of the tangential cell walls, little to hardly any thickening on the radial walls)
• Gap collenchyma (strong cell wall thickening around the large intercellular areas, little to no thickening at cell-cell contacts )

An example of a corner collenchyme is the pumpkin (Cucurbita pepo) , for a plate collenchyme the potato (Solanum tuberosum) , which already represents a transition to the joint collenchyme, and the tobacco (Nicotiana tabacum) , which has a joint collenchyme.

Individual evidence

1. ^ Wilhelm Nultsch : General botany . 11th edition. Thieme, Stuttgart 2001, ISBN 3-13-383311-1 .
2. ^ Theodor Dingermann, Wolfgang Kreis, Horst Rimpler, Ilse Zündorf: Reinhard - Pharmaceutical Biology . 7th edition. Part 1. Wissenschaftliche Verlagsgesellschaft, Stuttgart 2009, ISBN 978-3-8047-2107-4 .
3. ^ Theodor Dingermann, Wolfgang Kreis, Horst Rimpler, Ilse Zündorf: Reinhard - Pharmaceutical Biology . 7th edition. Part 1. Wissenschaftliche Verlagsgesellschaft, Stuttgart 2009, ISBN 978-3-8047-2107-4 .

Web links

Commons : Kollenchym  - collection of images, videos and audio files