Estimation for the timing of the internal developmental processes of acorns from fruit size in Quercus serrata Thunb. ex Murray

Abstract

To evaluate the relative importance of the factors affecting the premature abortion of acorns in Quercus serrata Thunb. ex Murray during the course of their development, inner developmental processes of acorns were observed by microscope, and applicability of the diameter of fruits (acorns with cupules) as an indicator of the inner developmental processes was discussed. Based on the observations using microscope, the developmental processes of acorns were classified into five stages; one prezygotic and four postzygotic stages (stages I to V). The diameter of sound fruits increased exponentially until 14 weeks after pollination, and the variance of diameter in each tree was fairly small (CV = ∼6%) during the process. Diameter of fruits can be used as a good indicator of developmental stages of acorns at individual level, and effective for the evaluation of the ecological factors affecting the premature abortion of acorns.