LIGHT OR POLLEN - SEASONAL LIMITATIONS ON FEMALE REPRODUCTIVE SUCCESS IN THE UNDERSTORY SHRUB LINDERA-BENZOIN

1. Light, pollen, and leaf area were manipulated to examine the role of each of these as determinants of reproductive success in the understory shrub Lindera benzoin. 2. Fruit set was significantly greater in the sun than in the shade, and was reduced in both habitats by shading branches. 3. Supplemental pollination added significantly more viable pollen to stigmas, but plants never responded with increased fruit set, even under conditions of high light availability. 4. Treatments had no effect on fruit and seed mass. but there was a significant maternal effect on these variables. 5. Treatments did result in a significant reduction in per branch flower production in the following year, especially on fruit-bearing branches in shaded sites and on artificially shaded branches. 6. Defoliations at the level of the branch significantly reduced fruit maturation. 7. The data indicate that branches within plants are somewhat physiologically autonomous; and, because light can affect fruit/seed set and flower production in this understory plant, gap dynamics may play an important role in its reproductive ecology.