The effect of cycloheximide and 6-methylpurine on in vivo compatible and incompatible pollen tube growth in Lilium longiflorum.

Cycloheximide, a potent inhibitor of protein synthesis, placed in styles of Lilium longiflorum at 10(-4) M in stigmatic exudate before, 6, or 12 hr after compatible or incompatible pollination retarded all pollen tube growth. An inhibitor of RNA synthesis, 6-methylpurine, placed in the style at 10(-4) M in stigmatic exudate before, 6, or 12 hr after pollination restricted compatible pollen tube growth to lengths not significantly different thanincompatiblepollen tubes in treated or nontreated styles. While pollen tube growth in the style of L. longiflorum appears to require protein synthesis, only compatible pollen tube growth requires RNA synthesis. Stigmatic exudate proved to be an excellent carrier of exogenous substances into the style of L. longiflorum.