Chromoplast

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chromoplast

[′krō·mō‚plast]
(cell and molecular biology)
Any colored cell plastid, excluding chloroplasts.

Chromoplast

 

a pigmented intracellular organelle of plant cells; a type of plastid. Chromoplasts may be spherical, spindle-shaped, sickle-shaped, or irregularly polygonal. Their orange, yellow, or brownish coloring is caused principally by carotenoids. Chromoplasts are usually formed from green plastids—chloroplasts—as green chlorophyll pigments are destroyed in the process of the ripening of the fruits of certain plants, such as mountain ash, lily of the valley, and persimmon, and during the autumn yellowing of leaves. At this stage the protein-lipid membrane of the chloroplast system decomposes. The protein flows out of the plastids, while the lipid remains inside, dissolving the carotenoids, which color the plastids orange and yellow. In some instances the chromoplasts are formed from colorless plastids—leukoplasts—for example, in carrot roots.

REFERENCES

See references under PLASTIDS.
References in periodicals archive ?
Quinone compounds are able to replace molecular oxygen as terminal electron acceptor in phytoene desaturation in chromoplasts of Narcissus pseudonarcissus L.
CPTA modulates levels of carotenogenic proteins and their mRNAs and affects carotenoid and ABA content as well as chromoplast structure in Narcissus pseudonarcissus flowers.
First, in strictly anemophilous species, such as Lolium perenne, plastids first develop into chromoplast, later in elaioplast, and then are resorbed with the other tapetal cell components (Pacini et al., 1992a).
carotenoids pigments: Plant cell pigments: red, orange, and yellow lipid soluble pigments found embedded in the membrane of chloroplast and chromoplast.
The carotenoids that impart yellow through orange colors are found within other small cell packets called chromoplasts.
rapid degradation of chlorophyll and a progressive accumulation of carotenoids mostly lycopene and [beta]-carotene as the chloroplast are transformed to chromoplasts [8, 9].
Such aspects as crystallinity, crystal size and the location of the carotenoids in the sub-cellular structures (chloroplasts and chromoplasts) are important.