Development of stigmatoid anthers in a tobacco mutant: implications for regulation of stigma differentiation

摘要

We characterized the development of a tobacco floral mutant,Mgr27, previously obtained by selecting for resistance to an inhibitor of an enzyme in the polyamine biosynthetic pathway.Mgr27plants are shorter than the wild type with smaller leaves and a compact inflorescence. The plants have a regular leaf plastochron and a vegetative shoot apex similar to the wild-type vegetative shoot apex. There are frequently more than five floral organs in the first three whorls, and the anthers produce stigmatoids. At the scanning electron microscope level, the stigmatoids appear concurrently on all of the anthers and at approximately the same time that the stigma appears on the pistil. The stigmatoids contain tissue histologically and biochemically similar to transmitting tissue and they permit the germination and growth of pollen tubes. The mutant line has significantly lower levels of free and conjugated spermidine as well as significantly lower levels of conjugated putrescine.Key words: floral development, mutant,Nicotiana tabacum(tobaccco), polyamines, stigmatoid anthers.