IMPLICATIONS OF NUCLEOLAR DIFFERENCES IN THE ROOT EPIDERMIS AMONG SEVERAL GRASS SPECIES

The nucleolar sizes of root epidermal cells were determined in 10 species of the Gramineae. Festucoid and panicoid roots presented significantly larger nucleoli in hair-producing, as opposed to hairless, cells. The magnitude of the nucleolar size differences between cell types seemed to be species specific and was not related to the type of epidermal cellular pattern. There seemed to be some suggestion that meristematic nucleoli of festucoid species may generally be larger than those of panicoid types. There was also an indication that festucoid grasses might be characterized by a high percent of multinucleolate epidermal cells. In contrast, cells of panicoid roots contained a single nucleolus in most instances. Possible implications of these observations were briefly discussed in terms of development and systematics.