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Pyrena

Diagram of a typical drupe, in this case a peach, illustrating the layers of both the fruit and the seed; the pyrene is the hardened endocarp which encloses the seed

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.[1] It consists of a hard endocarp tissue surrounding one or more seeds (also called the "kernel").[2][3] The hardened endocarp which constitutes the pyrene provides a protective physical barrier around the seed, shielding it from pathogens and herbivory.[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]

Development

The hardening of the endocarp of a developing drupe occurs via secondary cell wall formation and lignification.[4] The biopolymer lignin, also found in wood, provides a structure within secondary cell walls which supports the polymerisation of cellulose and hemicellulose; together these polymers provide the endocarp with tensile strength and stiffness.[4] Further hardening occurs during the biomineralisation of the endocarp. The biomineralisation of pyrenes during the life of the plant can aid the preservation of fruit remains in archaeological findings.[6][7]

Gallery

See also

References

  1. ^ Eckel (2011).
  2. ^ Beentje & Williamson (2010).
  3. ^ Hickey & King (2001).
  4. ^ a b c Dardick & Callahan (2014).
  5. ^ Potter et al. (2007).
  6. ^ Allué et al. (2015).
  7. ^ Messager et al. (2010).

Bibliography