Leucoplast

Leucoplasts are a category of plastid and as such are organelles found in plant cells. They are non-pigmented, in contrast to other plastids such as the chloroplast.

Lacking pigments, leucoplasts are not green, so they are predictably located in roots and non-photosynthetic tissues of plants. They may become specialized for bulk storage of starch, lipid or protein and are then known as amyloplasts, elaioplasts, or proteinoplasts respectively. However, in many cell types, leucoplasts do not have a major storage function and are present to provide a wide range of essential biosynthetic functions, including the synthesis of fatty acids, many amino acids, and tetrapyrrole compounds such as haem. In general, leucoplasts are much smaller than chloroplasts and have a variable morphology, often described as amoeboid. Extensive networks of stromules interconnecting leucoplasts have been observed in epidermal cells of roots, hypocotyls and petals, and in callus and suspension culture cells of tobacco. In some cell types at certain stages of development, leucoplasts are clustered around the nucleus with stromules extending to the cell periphery, as observed for proplastids in the root meristem.

Etioplasts, which are pre-granal, immature chloroplasts but can also be chloroplasts which have been deprived of light, lack active pigment and can technically be considered leucoplasts. After several minutes exposure to light, etioplasts begin to transform into functioning chloroplasts and cease being leucoplasts.

Compare

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

External links

* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&list_uids=15699062&dopt=Abstract Stromules: a characteristic cell-specific feature of plastid morphology.] : A good review on stromules (unfortunately access is restricted to suscribers)


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Look at other dictionaries:

  • leucoplast — LEUCOPLÁST, leucoplaste, s.n. Fâşie de ţesătură impregnată cu cauciuc, lipicioasă pe o parte, folosită la fixarea pansamentelor. [pr.: le u . – pl. şi: leucoplasturi] – Din germ. Leukoplast, fr. leucoplaste. Trimis de LauraGellner, 20.05.2004.… …   Dicționar Român

  • Leucoplast — Leu co*plast (l[=u] k[ o]*pl[a^]st), Leucoplastid Leu co*plas tid ( pl[a^]s t[i^]d), n. [Leuco + Gr. pla ssein to mold.] (Bot.) One of certain very minute whitish or colorless granules occurring in the protoplasm of plants and supposed to be the… …   The Collaborative International Dictionary of English

  • leucoplast — [lo͞o′kō plast΄] n. [ LEUCO + PLAST] any of the colorless granules found in the protoplasm of vegetable cells in which starch forms in the absence of light …   English World dictionary

  • leucoplast — noun Etymology: International Scientific Vocabulary Date: 1886 a colorless plastid especially in the cytoplasm of interior plant tissues that is potentially capable of developing into a chloroplast …   New Collegiate Dictionary

  • leucoplast — Colourless plastid, that may be an etioplast or a storage plastid (amyloplast, elaioplast or proteinoplast) …   Dictionary of molecular biology

  • leucoplast — /looh keuh plast /, n. Bot. a colorless plastid in the cells of roots, storage organs, and underground stems, serving as a point around which starch forms. [1885 90; LEUCO + PLAST] * * * …   Universalium

  • leucoplast — noun An organelle found in certain plant cells, a non pigmented category of plastid with various biosynthetic functions …   Wiktionary

  • leucoplást — (farm.) s. n. (sil. le u, plast), pl. leucopláste …   Romanian orthography

  • leucoplast — [ lu:kə(ʊ)plast, plα:st] noun Botany a colourless organelle found in plant cells, used for the storage of starch or oil …   English new terms dictionary

  • leucoplast — leu·co·plast …   English syllables

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