title: Ecological significance of seed desiccation sensitivity in Quercus ilex.
abstract: OBJECTIVE
  Several widespread tree species of temperate forests, such as species of the genus Quercus, produce recalcitrant (desiccation-sensitive) seeds. However, the ecological significance of seed desiccation sensitivity in temperate regions is largely unknown. Do seeds of such species suffer from drying during the period when they remain on the soil, between shedding in autumn and the return of conditions required for germination in spring?
  
  
  METHODS
  To test this hypothesis, the Mediterranean holm oak (Quercus ilex) forest was used as a model system. The relationships between the climate in winter, the characteristics of microhabitats, acorn morphological traits, and the water status and viability of seeds after winter were then investigated in 42 woodlands sampled over the entire French distribution of the species.
  
  
  RESULTS
  The percentages of germination and normal seedling development were tightly linked to the water content of seeds after the winter period, revealing that in situ desiccation is a major cause of mortality. The homogeneity of seed response to drying suggests that neither intraspecific genetic variation nor environmental conditions had a significant impact on the level of desiccation sensitivity of seeds. In contrast, the water and viability status of seeds at the time of collection were dramatically influenced by cumulative rainfall and maximum temperatures during winter. A significant effect of shade and of the type of soil cover was also evidenced.
  
  
  CONCLUSIONS
  The findings establish that seed desiccation sensitivity is a key functional trait which may influence the success of recruitment in temperate recalcitrant seed species. Considering that most models of climate change predict changes in rainfall and temperature in the Mediterranean basin, the present work could help foresee changes in the distribution of Q. ilex and other oak species, and hence plant community alterations.
authors: IRD, UMR DIADE, BP 64501, Montpellier, France. thierry.joet@ird.fr
authors: Thierry
authors: T
authors: Joët
authors: Jean-Marc
authors: JM
authors: Ourcival
authors: Stéphane
authors: S
authors: Dussert
mesh_terms: D003890:Desiccation; D017753:Ecosystem; D005602:France; D014644:Genetic Variation; D029963:Quercus / Q000502:physiology*; D012621:Seasons; D012639:Seeds / Q000502:physiology*; D013696:Temperature; D014197:Trees
references: Philos Trans R Soc Lond B Biol Sci. 2009 Apr 27;364(1520):1059-74
references: 19324611
references: Oecologia. 2008 Mar;155(3):529-37
references: 18075760
references: Plant Cell Environ. 2010 Jan;33(1):59-75
references: 19843255
references: Ann Bot. 2006 Apr;97(4):667-74
references: 16464874
references: PLoS One. 2012;7(10):e47368
references: 23071795
references: Proc Natl Acad Sci U S A. 2006 Nov 7;103(45):16812-7
references: 17068126
references: Am J Bot. 2004 Jun;91(6):863-70
references: 21653442
references: Evolution. 1998 Aug;52(4):988-997
references: 28565208
references: Mol Ecol. 2002 Nov;11(11):2327-36
references: 12406243
references: New Phytol. 1992 Oct;122(2):273-279
references: 33873988
references: Ecol Lett. 2012 Jun;15(6):533-44
references: 22433068
references: Funct Plant Biol. 2006 Feb;33(1):59-66
references: 32689214
references: J Insect Physiol. 1998 Nov;44(11):1091-1101
references: 12770408