ADH isozymes in seed of Nicotiana species and somatic hybrids

Initial studies confirmed the presence of active alcohol dehydrogenase (ADH) in extracts from dry seed of Nicotiana tabacum. Iso- or aliozymes could be separated on horizontal 12 percent hydrolyzed starch gels. ADH zymograms were ascertained for a total of 20 Nicotiana species. Five Nicotiana species yielded banding patterns identical to N. tabacum. Of the remaining 14 species, nine were clearly distinguishable from N. tabacum, two had a multiple banding pattern that included the N. tabacum band, and three expressed bands separated by an insufficient distance to be clearly distinguished from N. tabacum in the hybrid state. Separation distance was improved for one of the three latter species, N. glutlnosa, by altering the pH of the gel system. The dimeric nature of ADH in tobacco was confirmed by the occurrence of a heteropolymer in three different hybrids. Finally, sufficient ADH activity was present in a single seed of N. tabacum to yield a visible band suggesting a quick and inexpensive test for seed stock purity and genetic segregation in hybrids.