Inactivation of self-incompatibility following temperature pretreatments of styles in Lilium longiflorum

Incompatible (self) pollen tube growth in styles of six cultivars of L. longiflorum is strikingly influenced by treatment of the styles for six minutes in 50°C distilled water prior to pollination. In pretreated detached styles the incompatible pollen tubes reach lengths normally attained by compatible pollen whereas in untreated styles they grow to only approximately two-thirds the length normally reached by compatible tubes. Pretreatment at either 25°C or 45°C for six minutes does not affect incompatible pollen tube growth. Both compatible and incompatible tubes grow only a few millimeters into styles treated at 55°C for six minutes. Stigmatoid cells in these styles appear necrotic. Pretreatment of attached styles at 50°C for six minutes resulted in fruit set following self-pollination. Seed number per capsule ranged from 6 to 114. Stylar pretreatment appears to be a highly promising approach to further investigation concerning the nature of the self-incompatibility reaction. It also appears to offer a suitable means of obtaining seed from self-incompatible plants.Paper No. 1096 from the Laboratory of Genetics, University of Wisconsin. Supported in part by a grant from the National Science Foundation.