In the 1976 News Letter we presented a figure of a thin-layer chromatogram showing some of the more common flavonoids found in W22 seedlings. Quantitative comparisons with other lines are difficult in strains with strong anthocyanin concentrations because the anthocyanin spots tend to overlap those of other flavonoids. In bz seedlings, anthocyanins are rarely present, and then only in trace amounts. Quantitative measurements of other compounds are thus possible, in particular the flavones and flavonols. The bz allele affects flavonol concentrations as well as anthocyanins, of course, but the effect on flavonols seems to differ markedly in different backgrounds. We are presently investigating these background effects, and a summary of our findings so far is as follows (the figure shows those flavonoids specifically referred to in this article):
1. W22 P-WR A A2 R-r bz Pr B-b pl: Flavonols markedly reduced in comparison with Bz strains. Qu1 is the only flavonol present in measurable amounts. Flavone concentrations apparently unaffected by the bz allele.
2. K55 P-WW A A2 R-r bz Pr b pl (kindly supplied by E. H. Coe): Virtually no flavonoids in coleoptile. Other K55 Bz strains from Coe's stocks show only traces of flavones (as expected with the P-WW allele) and mostly Qu1 and Qu2 flavonols.
3. W23 P-WR A A2 R-r bz Pr b pl (again kindly supplied by E. H. Coe): Strong concentrations of flavones. Qu1, Qu11, Qu2, Qu22 and Qu3 all present, as well as several other minor flavonol spots. Some luteolinidin, and traces of cyanidin 3- and 5-glycosides. Other W23 Bz stocks from Coe show mostly Qu1 and Qu11, with Qu2 and Qu22 increasing with increasing anthocyanin concentrations. Some luteolinidin, but no Qu3 or cyanidin 5-glycosides.
4. F1 seedlings from crosses between the K55 and W23 bz stocks described above have approximately half the concentrations of all flavonoids found in the W23 bz parent. Some F2 seedlings have values in excess of those found in the W23 bz stocks. In general, the P-WR segregants have higher concentrations of all flavonoids, including flavonols. Most of the P-WW F2 seedlings, as well as P-WW seedlings from F1 x K55 bz backcrosses, have measurable amounts of all flavonoids, including flavones, in their coleoptiles.
5. P-WR A A2 R-r bz plants extracted from W22 P-WR A A2 R-r bz x P-WW a A2 R-g Bz (ex Co-op) by selfing show segregation for Qu3 concentrations; presence of Qu1 and Qu11 but traces only of Qu2 and Qu22; and conversely, presence of Qu2 and Qu22 but traces only of Qu1 and Qu11. Traces of cyanidin 5-glycosides are present in most plants. P-WW A A2 R-r bz sibs have reduced concentrations of all flavonoids.
6. C-GF1 is the flavone commonly found in most stocks that we have analyzed. A few stocks have C-GF2 as the predominant flavone. The difference appears to result from a single genetic factor, as far as we can tell not one presently recognized as being involved with any other phenotype.
Oldriska Ceska and Derek Styles
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