| Abstract: | A comparison of four volumes of culture vessel atmosphere revealedthat this variable greatly influenced the induction and growthof pollen embryos from anthers of Nicotiana tabacum. The optimumfrequency of anthers producing embryos and plantlets was foundwith a culture atmosphere of 15 ml per anther, whereas the optimumnumber of plantlets was found with 5.5 ml per anther. A smallvolume (0.5 ml per anther) almost completely suppressed embryoinduction. Removal of specific components of the culture atmosphere(ethylene, carbon dioxide, oxygen) influenced the response ofthe anthers but did not produce a satisfactory explanation ofthe inhibition of pollen embryogenesis by the small cultureatmosphere volume. In particular, the influence of ethyleneabsorption on embryo induction and growth depended both on theculture atmosphere volume and on the stage of development ofthe pollen at the start of culture. Using anthers containingpollen at a stage after the first pollen grain mitosis. ethyleneabsorption was found to increase the survival of induced embryos.Treatment of anthers for 3 d with silver nitrate, a known antagonistof ethylene action, was not an efficient means of increasingthe yield of pollen plantlets. |
