Fruit and seed production in relation to pollination and resources in bluebell, Hyacinthoides non-scripta

Abstract

This paper explores spatial and temporal patterns in the interaction of pollination and resources as constraints on the initiation and maturation of fruits and seeds in bluebell (Hyacinthoides non-scripta, Liliaceae). Field and laboratory experiments showed a degree of self-incompatibility (cross-pollination gave greater seed and fruit numbers than self-pollination), and pollinator limitation (hand cross-pollination gave greater seed and fruit numbers than open-pollination) as well as␣resource limitation. Bud removal, designed to relax interfruit competition for resources in the remaining flowers, increased percent fruit maturation in unpollinated flowers and increased the percent of initiated seeds that matured in cross-pollinated flowers. Clear position effects were also found. In an ovary, ovules near the stylar end showed a higher percent seed maturation than basal ovules. On a raceme, terminal flowers showed lower percent fruit initiation and maturation and lower seed numbers than basal flowers. The balance between resource limitation and pollinator limitation changed with position on the raceme. Temporal patterns involved raceme death and abortion of flowers, fruits or seeds. A lattice diagram schematises the hypothetical modulation by pollination of resource-dependent serial adjustment of maternal investment.