Statolith

statolith [′stad·ə‚lith]

(botany)

A sand grain or other solid inclusion which moves readily in the fluid contents of a statocyst, comes to rest on the lower surface of the cell, and is believed to function in gravity perception.

(invertebrate zoology)

A secreted calcareous body, a sand grain, or other solid inclusion contained in a statocyst.

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Statolith 

(1) A synonym for otolith.

(2) In plants, a small mobile starch grain found in cells of the rootcap, tips of cereal coleoptiles, and other growing parts. When the direction of the axis of the organ changes, the statoliths drop and exert pressure on the cytoplasm, resulting in geotropic bending of the organ. Statoliths are consumed by the plant during severe starvation, for example, when there is prolonged darkness. The cells that contain statoliths are called statocysts.