Meristem förökad
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Meristematic Tissue
Meristematic tissue, commonly called meristem, is a group of undifferentiated cells that remain young and divide indefinitely throughout plant life. Cells in the meristem can develop into any tissues and organs in plants.
Thus, meristems are the område of active growth in plants. They are mainly found in the skott and root apices that give rise to new organs and allow plants to grow and repair worn-out tissues.
In , Carl Wilhelm von Nägeli coined the begrepp ‘meristem’. The term ‘meristem’ originated from the Greek word ‘merizein’, meaning ‘to divide.’
Characteristics of Meristematic Tissue in Plants
Meristems have some unique characteristics. They are:
- Can self-renew and self-sustain indefinitely. When meristems divide bygd mitosis, the cell that remains in the meristem is called an första, and the other fryst vatten the derivative. As new cells add up bygd repeated divisions of the initial cells, the derivative cells gets pushed away from the zone of active division. As they mature, the derivatives differentiate into other types of tissues.
- They are small and cuboidal in shape.
- Have a single, large, and prominent nucleus
- Contain small vacuoles, thin cell
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Meristem
Type of plant tissue involved in cell proliferation
This article is about a plant tissue. For other uses, see Meristem (disambiguation).
In cell biology, the meristem is a structure composed of specialized tissue found in plants, consisting of stem cells, known as meristematic cells, which are undifferentiated cells capable of continuous cell division. These meristematic cells play a fundamental role in plant growth, regeneration, and acclimatization, as they serve as the source of all differentiated plant tissues and organs. They contribute to the formation of structures such as fruits, leaves, and seeds, as well as supportive tissues like stems and roots.[1]
Meristematic cells are totipotent, meaning they retain the ability to differentiate into any plant cell type. As they divide, they generate new cells, some of which remain meristematic while others differentiate into specialized cells that typically lose the ability to divide or produce new cell types. Due to their active division and undifferentiated nature, meristematic cells form the foundation for the formation of new organs and the continuous expansion of the plant body throughout the p
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Méristème
Chez les plantes terrestres, un méristème (du grec μεριστός&#;/ meristós, «&#;partagé, divisé&#;») est une zone de division cellulaire, à l’origine d’organes et/ou de tissus végétaux (ce n’est pas un tissu, car formé de cellules indifférenciées)[1]. Les cellules méristématiques indifférenciées se divisent (mitoses) puis se différencient en acquérant une structure et une fonction. On distingue habituellement les méristèmes primaires qui assurent la croissance de la plante en longueur au niveau de la tige, des feuilles et des racines, et les méristèmes secondaires, responsables de la croissance en épaisseur de certains organes (dits à croissance secondaire) chez certaines plantes (le tronc des arbres par exemple)[2]. Chez les végétaux, les méristèmes permettent une croissance infinie.
Description
[modifier | modifier le code]Un méristème est un groupe de cellules végétales indifférenciées qui ont la capacité de se diviser par mitose un nombre indéfini de fois[3]. Les cellules du méristème sont aussi appelées «&#;initiales&#;»[4].
Méristèmes et développement
[modifier | modifier le code]Mousses et ptéridophytes
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