Problems Encountered in the Culture of Isolated Pollen of a Burley Cultivar ofNicotiana tabacum

Abstract

Pollen isolated from anthers of a Burley cultivar of N. tabacum by an anther homogenization procedure failed in culture to retain viability and produce plantlets even when isolation was preceded by 14 d of anther preculture. By surgical manipulation of anthers prior to their culture it was shown that pollen viability was very sensitive to injury caused to the anther wall. Plantlets could be obtained however by culture of anthers in which one or both pollen sacs had been carefully opened along the dehisence line (DL). The somewhat lower yield of plantlets from such anthers compared to that from intact anthers is considered to result not from any change in the atmospheric environment of the pollen as a result of opening the pollen sac but from the inability in every case to keep the incisions strictly along the dehiscence line. Pollen isolated from 14 d precultured anthers by this DL technique was able to yield plantlets when cultured in a simple defined medium. However DL-isolated grains from 4 d precultured anthers failed to retain viability in culture. It is concluded that pollen of this cultivar suffers severe injury when isolated by the homogenization method and that this can be overcome by the DL technique. However conditions of culture have not been established which reproduce for this cultivar the nutritional conditions operating within the anther during its early period in culture and which are essential to plantlet formation.