Chromoplast

Chromoplasts ( from Ancient Greek χρῶμα chroma "color" and ancient Greek πλαστός plastos "formed" ) are plastids containing xanthophylls or carotenes and parts of plants, in which they occur, yellow, orange or red ( instead of green as the chloroplasts ) color. You not photosynthesize and serve the attraction of animals ( for the transfer of pollen and seed dispersal ) or stem (as with red tomatoes) the aging process. Sometimes, however, they have no environmental benefits, such as in the carrot, the orange coloring underground can attract not an animal. The chromoplasts are responsible for many flower colors and colors of many fruits or roots, such as in the red or yellow bell pepper or carrot. The chromoplasts of flower petals and fruit may arise from leucoplasts or young chloroplasts. Like all plastids contain circular DNA in multiple copies, and thus the complete plastome. They also carry special synthesis services (eg pigment synthesis), but have no chlorophyll and therefore are photosynthetically inactive. The exception of small amounts of some plants also contain chromoplasts chlorophyll (eg, brown algae ). Chromoplasts, as well as the chloroplasts in fat more soluble than in water.

Due to certain support structures on which the carotenoids ( carotenes and xanthophylls ) are attached, different types of chromoplasts are distinguished:

• Globular type It contains lipid globules (diameter 0.2-1 microns ), in which the pigments are enriched. They correspond to the plastoglobules.
• Tubular type chromoplasts The look in the electron microscope as tubes, but are thread- shaped liquid crystals, which are surrounded by an envelope of lipids and the protein fibrillin.
• Crystalloid type These have a rectangular or rhombic structure, but there are only about 20-45 % of beta -carotene.
• Membranous type as the carrier of pigments act membranes, which are nested in the form of numerous concentric hollow spheres.