Desiccation-tolerance of Fagus crenata Blume Seeds from Localities of Different Snowfall Regime in Central Japan

Abstract

In beech (Fagus crenata Blume) forests on the Pacific Ocean side in Central Japan, snowpack depth is little and xeric conditions may prevail in winter, in contrast to heavy snow in beech forests on the Japan Sea side. The effects of such conditions during winter on the viability of beech seeds were studied at a beech forest on the Pacific Ocean side. Thickness and weight ratio of pericarp of beech seeds were significantly greater in populations on the Pacific Ocean side compared to the Japan Sea side, this apparently being related to snowpack depth in winter. During the initial stage of seed drying, the drying rate of seeds from the Fuji population (the Pacific Ocean side) was less than that from the Sumon population (the Japan Sea side), possibly due to the thicker pericarp. Germination percentage of seeds which dried to a water content as low as 7% d.w. did not decrease for either population, indicating desiccation tolerance of beech seeds. In the beech forest (University Forest at Yamanaka) on the Pacific Ocean side, water content of seeds sown below litter from both populations remained sufficient for viability during winter. Germinating seeds from the populations on the Japan Sea side were more desiccation-sensitive in early spring, compared to those from the Fuji population, partially due possibly to differences in pericarp thickness.