Relationship between pectin content of stems of flax cultivars, fungal cell wall‐degrading enzymes and pre‐harvest retting

SUMMARY Of five flax cultivars suitable for fibre production Ariane retted most rapidly and Belinka and Hera were the slowest to ret after treatment with the herbicide glyphosate. Prematurely senescing stems of the different cultivars bore the same populations of saprophytic, filamentous fungi. More polygalacturonase (PG) activity was detected in retting, naturally‐colonised stems of Belinka, Hera and Regina than in stems of Ariane or Natajsa but pectin‐lyase (PL) activities were not significantly different. The pectic substance content of stem cell walls varied between cultivars; Hera and Belinka contained significantly the greatest amount, 34‐0 and 32‐5% w/w respectively and Ariane contained the least, 26‐3% w/w. Significant differences in xylan content of cell walls were not obtained but the highest levels of xylanase activity were detected in colonised stem tissues of Belinka. Fibres of this cultivar were found to be slightly weaker than those of the other cultivars but also the finest.