information:filtering, structural:scholar_edition
Natural occurrence

Alkenes are prevalent in nature.Plants are the main natural source of alkenes in the form of terpenes. Many of the most vivid natural pigments are terpenes; e.g. lycopene (red in tomatoes), carotene (orange in carrots), and xanthophylls (yellow in egg yolk). The simplest of all alkenes, ethylene is a signaling molecule that influences the ripening of plants.