Pulvinus

As pulvini ( singular: pulvinus ) are thickened places designated in the stems or at the base of the pinnae of plant leaves, which act as joints. They allow relatively rapid, growth- independent movements ( Nastien ), such as various daily leaf movements that occur among others, acacias and mimosas.

Anatomically they consist of a central vascular bundle, which is surrounded by thin-walled parenchyma cells. By absorption or emission of mainly potassium ions latter cells can change their turgor pressure and thus expand or contract. An extension on the top of the parenchyma Pulvinus results in downward movement of the associated member, and vice versa.

Swell

  • Peter H. Raven, Ray F. Evert, Susan E. Eichhorn: Biology of Plants. 3 edition. de Gruyter, Berlin, New York 2000, ISBN 3-11-015462-5.
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