Diagram of a typical drupe, in this case apeach, illustrating the layers of both the fruit and the seed; the pyrene is the hardenedendocarp which encloses theseed
This article is about fruitstones. For the organelle within the chloroplast of some algae and hornworts, seepyrenoid. For other uses of "pyrene", seePyrene (disambiguation).
Apyrena (/paɪˈriːnə/) orpyrene, commonly called apit orstone, is thefruitstone within adrupe ordrupelet produced by theossification of the endocarp or lining of the fruit.[1] It consists of a hardendocarp tissue surrounding one or moreseeds (also called the "kernel").[2][3] The hardened endocarp which constitutes the pyrene provides a protective physical barrier around the seed, shielding it frompathogens andherbivory.[4]
While many drupes are monopyrenous, containing only one pyrene,pome-type fruit with a hard, stony (rather than leathery)endocarp are typically polypyrenous drupes, containing multiple pyrenes.[5]
Cross-section of apeach, a monopyrenous drupe, cut to reveal the pyrene inside
Pyrene of apeach dissected to reveal a single seed inside
Pyrenes extracted from a single fruit ofCrataegus punctata, a polypyrenous drupe
X-ray of a pyrene ofElaeocarpus ganitrus revealing 10 seed-bearinglocules inside; the number of locules inE. ganitrus pyrenes is variable between individual fruits
Allué, Ethel; Cáceres, Isabel; Expósito, Isabel; Canals, Antoni; Rodríguez, Anna; Rosell, Jordi; Bermúdez de Castro, José María; Carbonell, Eudald (2015). "Celtis remains from the Lower Pleistocene of Gran Dolina, Atapuerca (Burgos, Spain)".Journal of Archaeological Science.53:570–577.Bibcode:2015JArSc..53..570A.doi:10.1016/j.jas.2014.11.016.
Beentje, H.; Williamson, J. (2010).The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms. Royal Botanic Gardens, Kew: Kew Publishing.
