Phragmites die-back: sulphide- and acetic acid-induced bud and root death, lignifications, and blockages within aeration and vascular systems.

Phragmites rhizome cuttings, and plantlets raised from seed, were exposed to the phytotoxins acetic acid or dissolved sulphide in unstirred solution cultures to determine whether die-back symptoms found in field-grown plants, and attributed to phytotoxin damage, could be induced. Many of the die-back symptoms associated with field sites, namely stunted adventitious roots and laterals, bud death, callus blockages of the gas-pathways, and vascular blockages, were all reproduced, and were particularly acute at the higher concentrations of the phytotoxins: acetic acid (1.67 mm), sulphide (1.4 mm). The results accord with the hypothesis that phytotoxins may play a critical role in Phragmites australis die-back.