– Development
– Hardening of endocarp via secondary cell wall formation and lignification
– Lignin provides structure in secondary cell walls
– Cellulose and hemicellulose polymers provide strength and stiffness
– Further hardening through biomineralisation
– Biomineralisation of pyrenes aids in fruit preservation
– Gallery
– Cross-section of peach reveals pyrene inside
– Dissected peach pyrene shows single seed
– Pyrenes from Crataegus punctata
– X-ray of Elaeocarpus ganitrus pyrene with locules
– Locules in E. ganitrus pyrenes vary
– See also
– Nut (fruit)
– References
– Eckel (2011)
– Beentje & Williamson (2010)
– Hickey & King (2001)
– Dardick & Callahan (2014)
– Potter et al. (2007)
– Bibliography
– Allué et al. (2015) on Celtis remains
– Beentje & Williamson (2010) on plant glossary
– Dardick & Callahan (2014) on fruit endocarp evolution
– Eckel (2011) on botanical Latin
– Messager et al. (2010) on biomineralization
A pyrena or pyrene (commonly called a "pit" or "stone") is the fruitstone within a drupe or drupelet produced by the ossification of the endocarp or lining of the fruit. It consists of a hard endocarp tissue surrounding one or more seeds (also called the "kernel"). The hardened endocarp which constitutes the pyrene provides a protective physical barrier around the seed, shielding it from pathogens and herbivory.
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.