What is "crenation"

Crenation \Cre*na"tion\ (kr?-n?"sh?n), n.

1. (Bot.) A rounded tooth on the edge of a leaf.

2. The condition of being crenate.

n. 1 The contraction of, or formation of abnormal notchings around, the edges of a cell after exposure to a hypertonic solution, due to the loss of water through osmosis, especially noticeable in red blood cells. 2 (context botany English) A rounded tooth on the edge of a leaf. 3 The condition of being crenate.

n. one of a series of rounded projections (or the notches between them) formed by curves along an edge (as the edge of a leaf or piece of cloth or the margin of a shell or a shriveled red blood cell observed in a hypertonic solution etc.) [syn: scallop, crenature, crenel, crenelle]

Crenation (from modern Latin crenatus meaning 'scalloped or notched', from popular Latin crena meaning 'notch') in botany and zoology, describes an object's shape, especially a leaf or shell, as being round-toothed or having a scalloped edge.

The descriptor can apply to objects of different types, including cells, where one mechanism of crenation is the contraction of a cell after exposure to a hypertonic solution, due to the loss of water through osmosis. In a hypertonic environment, the cell has a lower concentration of solutes than the surrounding extracellular fluid, and water diffuses out of the cell by osmosis, causing the cytoplasm to decrease in volume. As a result, the cell shrinks and the cell membrane develops abnormal notchings. Pickling cucumbers and salt-curing of meat are two practical applications of crenation.

Plasmolysis is the term which describes plant cells when the cytoplasm shrinks from the cell wall in a hypertonic environment. In plasmolysis, the cell wall stays intact, but the plasma membrane shrinks and the chloroplasts of the plant cell concentrate in the center of the cell.