Statolith

Statolith

Statoliths are a specialized form of amyloplasts involved in gravity perception by plants.

These specialized amyloplasts are denser than the cytoplasm and can sediment according to the gravity vector. They are found in a special subset of cells of the root cap (a tissue at the tip of the root) called statocytes. Statoliths are enmeshed in a web of actin and it is thought that their sedimentation transmits the gravitropic signal by activating mechanosensing channels. The gravitropic signal then leads to reorientation of auxin efflux carriers and subsequent redistribution of auxin streams in root cap and root as a whole. The changed relations in concentration of auxin leads to differerential growth of the root tissues. Taken together, the root is then turning, following the gravity stimuli.Statocyts are also found in the endodermic layer of the inflorescence stem. The redistribution of auxin causes the shoot to turn in a direction opposite that of the gravity stimuli. As these are a subclass of amyloplasts, they originally come from leucoplasts [missing reference !, this statement is in inconsistency with shown figure and with Buchanan et al (eds) Biochemistry and Molecular Biology of Plants; Rockville, Maryland] . All of these different 'plasts' come from proplastids.

Compare

*Plastid
**Chloroplast and etioplast
**Chromoplast
**Leucoplast
***Amyloplast
****Statolith
***Elaioplast
***Proteinoplast


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Look at other dictionaries:

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  • Statolith — Statolith, als Schwerekörper von höherem spezifischem Gewicht als dem der umgebenden Flüssigkeit in Schweresinnesorganen, den ⇒ Statocysten der Wirbellosen und den ⇒ Statolithenorganen der Wirbeltiere wirkender Körper, z.B. Sandkörnchen in den… …   Deutsch wörterbuch der biologie

  • statolith — [stat′əlith΄] n. [< Gr statos, standing (see STATOCYST) + LITH] 1. Bot. any of the small, freely moving concretions, often a starch grain, found in statocysts 2. Zool. OTOLITH (sense 2) statolithic adj …   English World dictionary

  • statolith — noun Etymology: International Scientific Vocabulary Date: 1900 1. any of the usually calcareous bodies suspended in a statocyst 2. any of various starch grains or other solid bodies in the plant cytoplasm that are held to be responsible by… …   New Collegiate Dictionary

  • Statolith — Otolithen eines Adlerfischs (von oben nach unten: Maßstab in mm, Innenseite, Außenseite) …   Deutsch Wikipedia

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  • statolith — n. [Gr. statos, fixed; lithos, stone] A movable concretion of granules of sand, lime, diatom shells, or quartz grains contained in a statocyst, that functions in equilibrium; lithite …   Dictionary of invertebrate zoology

  • statolith — (1) Bot. A type of amyloplast found in root tip cells of higher plants. It can sediment within the cell under the influence of gravity, and is thought to be involved in the detection of gravity in geotropism. (2) Zool. A sand grain or a structure …   Dictionary of molecular biology

  • statolith — statolithic, adj. /stat l ith/, n. 1. Zool. any of the granules of lime, sand, etc., contained within a statocyst. 2. Bot. an inclusion, as a starch grain, that by a change in position within the cells of an organ or part is assumed to cause a… …   Universalium

  • statolith — noun A specialized form of amyloplast involved in graviperception by plant roots and most invertebrates. Syn: otolith …   Wiktionary

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