Prefertilization barriers between different Bromeliaceae

Pollen germination on stigma, pollen tube growth in the style and pollen tu be penetration of ovules have been studied of excised pistils, after crossi ng and selfing of 7 bromeliad species. Prefertilization barriers were obser ved after intraspecific, interspecific and intergeneric crosses. Satisfacto ry pollen germination in both selfed and crossed flowers showed that the st igma did not act as a barrier. Self-incompatibility in Aechmea B and Tillan dsia A was confined in the style, which is characteristic for the gametophy tic SI system. Unilateral incongruity between Aechmea A and Aechmea B was n ot related to self-incompatibility, but could be explained by differences i n style length. Incompatibility, interspecific and intergeneric incongruity were different with respect to the number of pollen tubes in the style, ra tio of pollen tube length and style length, and the number of pollen tube a bnormalities. The prefertilization barriers of intergeneric crosses between different subfamilies were not greater than these observed within a subfam ily.