EFFECT OF FLORAL AGING ON THE GROWTH OF COMPATIBLE AND INCOMPATIBLE POLLEN TUBES IN LILIUM LONGIFLORUM

Compatible and incompatible pollen tube growth in detached styles of three Lilium longiflorum cultivare varies with the physiological age of the style. Before anthesis both compatible and incompatible pollen tubes grow, in 48 hr, only a fraction of the distance compatible tubes grow after anthesis. Incompatible pollen tubes are restricted to about half the distance of compatible tubes in the four days postanthesis, but thereafter increase up to or three‐fourths or more the length of compatible tubes at the time of floral senescence. About 10 days after anthesis, growth of both types of pollen tubes decreases. The detached style method of pollen‐tube cultivation is validated in the cultivar ‘Ace’ by seed set obtained following self‐pollination in the 6‐ to 9‐day interval and failure of seed set after either self‐ or cross‐pollination after 9 days following anthesis. Also, in agreement with detached style data, self‐pollination fails to produce seeds when attempted in bud stages or the five days following anthesis. Cross‐pollinations are successful in this period. This material and technique appear well suited for study of the nature of the self‐incompatibility reaction.