Seed production system of a young Castanopsis cuspidata stand
1994
Saito, H. (Kyoto Prefectural Univ. (Japan). Faculty of Agriculture)
In a young stand of Shii chinkapin, Castanopsis cuspidata, the yield of reproductive organ components was measured by the litter trap method, pollen production rates were estimated, and survey was made of the changes in numbers of male and female flowers/inflorescences from flowering to nut maturation. Compared with the other mature shii stands, production rates of male catkins in the young study stand were lower and those of female flowers wee equal. This difference produced small M/F and P/O ratios (male to female flowers / inflorescences and pollen to ovules on a land-area basis, respectively), representing high efficiency of seed production. Large year-to-year fluctuations in the production rates of male catkins were recognized, the maximum / minimum rate being 12. The decrease in the number of female flowers in an unproductive year was larger than that of male flowers. The large number of female inflorescences was reduced within a year after flowering and that of immature fruits was reduced from infructescences within the nut growing season of the following year. Little growth of immature fruits was recognized, corresponding to 3.0% of the mean weight of mature nuts. The proportion of infructescences borne in the nut growing season ranged from 6% in an unproductive year to 44% in a productive one. That of fruits ranged from 0.5% to 19%, of which the proportion of fruits that matured was about 60%, regardless of nut yield. The assimilation product necessary for producing a single nut was similar to that in other mature stands
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