Seed storability (i.e. seed perishability) has proven to be a particularly important factor for hoarding animals when selecting seeds for long-term caching, including those that scatter hoard seeds and typically facilitate seed dispersal. Acorns of many white oak species germinate soon after autumn seed fall, a characteristic widely interpreted as a general adaptation to escape predation by small rodents. However, the mechanism by which early, rapid germination allows escape and/or tolerance of seeddamage remains unclear. During germination, chestnut oak acorns develop elongated cotyledonary petioles, which extend beyond the apical end of the acorn (1 ~2 cm) to the point at which the epicotyl and radicle diverge. However, granivorous rodents oftenprune the taproots above or below the plumule when eating or caching these germinated acorns in autumn. Hence, we hypothesized elongation of cotyledonary petioles allows chestnut oaks to escape acorn pruning by rodents.
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