A mechanical study of retting in glyphosate treated flax stems (Linum usitatissimum)

The process of retting (the dissociation of the fibre bundles from the central stele by the action of microbes) in two varieties of flax (Linum usitatissimum; cvs. Laura and Escalina) was investigated by studying the morphology and mechanics of plants after treatment with a translocated herbicide, glyphosate. The mechanical changes in the stems were measured on a weekly basis, by carrying out a series of mechanical peel and tear tests on the stem tissue of mature plants. There was a pronounced drop in the moisture content of the stem 14 days after application of the herbicide, from a moisture content of ~60 to 10%. This was consistent with the onset of senescence and subsequent dehydration of the plant tissues. The dehydration of the stem tissues corresponded with an increase in the work required to peel the fibre bundles from the secondary phloem tissue, from 212±7.9 to 539±22 J m−2 (P