Variation of pollen tube behavior and seed set in self-pollination of Lilium longiflorum thunb

Quantitative variation in seed set following artificial self-pollination has been recently demonstrated in Lilium longiflorum. Pollen tube behavior and seed set in self-pollination in the species were investigated to clarify whether the variation is caused by self-incompatibility or early-acting inbreeding depression. The self pollen tubes were arrested in the style of the individuals that failed to set selfed seeds, and total number of pollen tubes observed at the base of the style tended to correspond to that of obtained selfed seeds. It indicates that decrease of selfed seed number in L. longiflorum is caused by self-incompatibility but not by early-acting inbreeding depression.