Assessing the effects of atmospheric ethylene on epinasty and tuber yield of potato (Solanum tuberosum L.) near polyethylene manufacturing plants

A multi-year programme was performed to assess the effects of atmospheric e thylene on potato (Solanum tuberosum L.) in the vicinity of polyethylene ma nufacturing plants. There was a strong temporal variation of the hourly eth ylene concentrations measured close to the sources from 1982 through 1991. Growing seasonal means exceeded 12 mu g m(-3) ethylene, the threshold for p hytotoxic effects under laboratory conditions. Young test plants of potato showed an epinastic response to enhanced levels of ethylene. This response was reversible and did not occur when atmospheric ethylene was not detected . Based on hourly observations for the growing seasons of 1984 through 1991 , epinasty occurred on average during circa 5% of the growing season and va ried from circa 1% in 1985 to circa 18% in 1991. At night, ethylene concent rations were higher and epinasty was more frequent than during daylight hou rs. The intermittent exposures to ethylene did not affect tuber yield for t he growing seasons of 1982 through 1990. The occurrence of epinasty indicat ed that ethylene exposure levels in the vicinity of the industrial sources might be sufficiently high to affect sensitive plants.