Chromoplasts

Part of speech: noun

Definitions

1. Organelles found in plant cells responsible for the synthesis and storage of pigments giving color to fruits and flowers
2. Structures within certain plant cells that produce and contain colored pigments for attracting pollinators or seed dispersers
3. Specialized parts of plant cells that hold pigments, contributing to the visible coloration in various parts of the plant

Etymology: Chromoplasts are plastids, the family of organelles in plant cells that also includes chloroplasts. The name combines the Greek "chrōma", meaning colour, with "plastos", meaning formed or moulded, a word that gave English "plastic" and "plaster". The term was coined in the late nineteenth century, when botanists studying plant cells under the microscope were naming the coloured bodies they saw. The surprising part is that the chromoplast's yellow, orange and red pigments are often the same kind of molecule that a chloroplast uses for light capture. Chloroplasts make green chlorophyll, but many of their carotenoid companions are visible only once the green fades. When a tomato ripens or a carrot root develops, chloroplasts can transform into chromoplasts, breaking down chlorophyll and building up carotenoids in their place. The organelle is thus the same structure reorganised, rather than a different cell part that happens to be coloured.