EXPERIMENTAL NON-STIGMATIC POLLINATIONS IN CLARKIA UNGUICULATA LINDL. (ONAGRACEAE)

Within angiosperms, the stigma-style apparatus provides a barrier to direct contact between ovules and the external environment. In traversing this barrier, male gametophytes presumably are subject to intense competition and natural selection. Successful fertilizations and resultant seed set can be accomplished following surgical decapitation of the stigma and style, provided that these normally receptive sites are replaced with an optimal environment suitable for pollen germination and growth. Unlike other methodologies, these in situ-in vitro pollinations are comparatively easily accomplished, and provide a means for circumventing natural fertility barriers; additionally, they may provide a simple means of artificially selecting pollen genomes. In Clarkia unguiculata 23.0% of attempted non-stigmatic pollinations produced outcrossed F₁ progeny.