Document: HYE-3-36-7

Temporal change in cone sex ratio in Pinus densiflora.

KANG, H.*

Sungshin Women's University, Korea ¹

Abstract:
Many pine species are characterized by a species-specific cycle of reproductive episode. The pattern of temporal variation in cone sex ratio was examined in populations of red pines in Korea. I evaluated: 1.) the relationship between tree size and sex ratio; 2.) the relationship between year and sex ratio; 3.) the relationship between sex ratio and pollen traits; and 4.) the relationship between the continuity of female cone production and sex ratio. Larger trees in height and dbh produced more male as well as female cones. However, the cone sex ratio was independent of these plant sizes. The cone sex ratio ranged from 275:1 to 1379:1 across populations and years. The effect of year on the cone sex ratio varied with population. Unlike the number of pollen grains, pollen diameter was significantly negatively correlated with the cone sex ratio in two of the three populations. Trees which produced female cones consecutively for two years tended to have lower cone sex ratio than those which did not; the former produced more female cones and larger pollen grains than the latter. These results show that reproductive periodicity, which is common in various pines, may cause further complexity in cone sex ratio by involving concordant changes in male and female cone numbers as well as pollen diameter.

Keywords: sex ratio, pollen traits, Pinus densiflora, resource allocation

This abstract is being presented at: 3:30 PM in session:
REPRODUCTIVE ECOLOGY