Flavonoid Chemistry of Diploid and Tetraploid Cytotypes of Tolmiea menziesii (Saxifragaceae)

Abstract

Flavonoid constituents of diploid (2n = 14) and tetraploid (2n = 28) populations were analyzed throughout the range of Tolmiea menziesii. The species contains kaempferol and quercetin 3-0-mono-, di, and triglycosides, as well as myricetin and isorhamnetin 3-0-monoand diglycosides. Minor variation in flavonoid constituents was observed among populations, but this was not correlated with ploidy. The qualitative identity in flavonoid constituents between the diploid and tetraploid cytotypes supports the contention that the tetraploid cytotype is of autopolyploid origin. Flavonoid data are therefore in agreement with evidence from gross morphology, karyology, floral anthocyanins, ribosomal genes, and enzyme electrophoresis, all of which support the hypothesis of autopolyploidy. Tolmiea Torr. & Gray (Saxifragaceae: Saxifrageae) comprises a single species, T. menziesii (Pursh.) T. & G., that ranges along the Pacific coast to the western side of the Cascades from southern Alaska to northern California. Soltis (1984) reported that Tolmiea has both diploid (2n = 14) and tetraploid (2n = 28) populations. Tetrapoloid populations have been detected from the northern limit of the distribution of the species in Alaska, southward through British Columbia and Washington to northern Oregon. All populations for which chromosome counts are available from south of central Oregon are diploid. Evidence from gross morphology and karyology suggests that Tolmiea represents a clear example of autopolyploidy (Soltis 1984). The genus is very distinct in both floral and vegetative morphology among genera of Saxifrageae. The two cytotypes appear to be indistinguishable morphologically and have identical basic and Hy-banded karyotypes (Soltis 1984). Although the flavonoids of Tolmiea were investigated previously by Bohm (1979), it was not known then that T. menziesii comprises both diploid and tetraploid populations. Furthermore, only six populations were sampled by Bohm. In order to provide additional systematic data regarding the hypothesized autopolyploid origin of tetraploid T. menziesii, we conducted a more thorough flavonoid investigation of diploid and tetraploid populations of this species. MATERIALS AND METHODS Twenty-nine population samples representing the range of Tolmiea menziesii were analyzed for flavonoid constituents. Two populations also were analyzed for intrapopulational variation in flavonoid constituents. General location data and ploidal level for the populations analyzed are provided in table 1. Most of the populations investigated herein were analyzed cytologically by Soltis (1984). Six populations from British Columbia and Alaska not investigated by Soltis (1984) were included in this study. Chromosome numbers were determined for these populations following the method of Soltis (1980). Flavonoids were extracted from dried leaves with 80% MeOH. The resultant extracts subsequently were prepared following the procedures of Wilkins and Bohm (1976) and Bohm et al. (1984). Purified flavonoids were analyzed using a combination of UV spectral methods (Mabry et al. 1970), acid hydrolysis, and thin layer chromatography against known compounds, when available (methods and solvent systems of Wilkins and Bohm 1976). Standards available for comparison included mono-, di-, and triglycosides. These three classes of compounds are clearly separated in aqueous-based 20 This content downloaded from 207.46.13.101 on Sun, 09 Oct 2016 04:19:59 UTC All use subject to http://about.jstor.org/terms 1986] SOLTIS & BOHM: TOLMIEA 21 Ipjso:rnj2jAsojAx-o-C +++ ++ +++ + + ++ 0 u 0 r aplsouilni-o-C 0 ts I I I P!SOU!1lJ-O-t + + +++ + + + + O I | p!SoflIelO-o-| + + + ++--+ + + + + u I | | > a ~~~~~~~~3TOUIfolJ-O-s ++ ?++ + + + + + I apot iAsoanj2ll-0I ++ +I+ I C+o aplsouilni-o-+ ++ +++ + + ++ X | I I ap olaeeS-o I ++ + + + + + + + + + 0 I'd | l a Isn-O-. + + + + + + + + 0 II 11 I lsoa {S A SOU fle -O. I + +p+ I + Inj + + + + O fpison| IAsuI cJ -ap os-o + + + + + + -+ + + + + ~i iso:nj2jAp!so)unuI p-o-C + + ++ + ++++ N = 11 1 a pl o la ele S o -t I + + + ++ ++ apTs:n2SOoj1fx-O-C +++ ++ + ++ + + + + 0al X | | I aIsoa + + + + + + + + + + + 0 aPlSOPujLW4.-O-c + ++ + + + ++ + + + + 30 1 1 s=: pu wUv2ao w g? a l:Lf + + + ~~~~~psOfl%O~+ + ?+ + + + + 0 aPjso:)nlIIAsouwLFi!.p-O-C + + + + I+ .b + + + 0 0 0 a~~.pjso)fn11Aso1Ax-Q-C + ++ + + + + + + + + o + ++ + + +++ + + + + o0 0 (D a~pisouUmrnp-o-C + + + ++ + + + + aPisopulug-O-C + + + + ++ + + + + aPjso:)njS-O-C +++ + ++ + + + + 04 'd ~~~~0 dCl4C C'4IC14C14 ci Cfl 4 N 0~~~~~~~~~ 0 CL4~~~~~~~~