Seed Storage, Dormancy, and Germination Behavior in Lithocarpus glaber (Fagaceae)

Abstract

Knowledge of seed storage behavior and germination ecology of Fagaceae species is limited to the Quercus genus, prompting the need to investigate other genera. Using Lithocarpus glaber (Thunb.) Nakai acorns collected from China, storage behavior, dormancy type, and germination pattern were investigated by germination and desiccation experiments along with triphenyl tetrazolium chloride (TTC) staining and photomicrographs. The fairly large-sized acorns with a mass of 1,340 g per 1,000 acorns had a moisture content of 34.5% (fresh weight) at the time of dispersal. There were three distinctive regions: (1) scar (hilum), (2) apex, and (3) pericarp, with an embryonic axis located on the apex side. When tested for germination at 15/20°C, 76.6% of the acorns germinated within the first 3 weeks, indicating nondormancy. However, germination declined to 48% and 3% when dried in silica gel to 26% and 17% moisture content, respectively, confirming the acorns are recalcitrant. Germination was hypogeal. Nonetheless, the elongated cotyledonary petiole establishes an intumescent tubular structure at approximately 7–10 cm from acorns, from which taproots and leaves emerge. The nondormant recalcitrant acorns took 6–8 weeks to complete the germination process (from imbibition to leaf emergence), possibly indicating the presence of epicotyl dormancy. This is the first study on Lithocarpus showing intumescent tubular structure development during germination. The ecological significance of this structure requires further investigation.