Iridoid glycoside and allozyme variation within and among populations of Plantago rhodosperma decne. (Plantaginaceae)

Abstract

To compare and contrast the inter- and intra-population variation in Plantago rhodosperma, individuals from four populations in Kansas (Russell, Woodston, Stockton A and Stockton B) were sampled. The following five characteristics were compared: (1) size of the plants, using area of the largest leaf as an index, (2) number of trichomes on the upper and lower leaf surfaces, (3) iridoid glycoside concentration of leaves and scapes, (4) leaf nitrogen concentration, and (5) allozyme variability. The Russell and Woodston populations were significantly smaller than those from Stockton A and B, and had greater trichome densities on the upper leaf surface. The Stockton B population had significantly more aucubin in the leaves than the other populations sampled. However, the aucubin concentration in the scapes did not differ among populations. The Stockton A and B populations had significantly higher leaf nitrogen concentrations than Russell, but Woodston was not significantly different from either of the other two. There was little inter- populational allozyme variation, although the Russell population showed allozyme variability among individuals for the enzyme PGI. The allozyme data suggest that P. rhodosperma is an allopolyploid.