Effects of chronic and acute exposure to sulphur dioxide on the growth of hybrid poplar cuttings
Abstract Hybrid poplar clones were fumigated in controlled-environment chambers with either 5 ppm sulphur dioxide for 1 1 2 , 3, and 6 h or with 0·25 ppm sulphur dioxide for six weeks. Multivariate analyses were made from shoot-growth data before and after treatment and on the foliar injury induced by SO 2 . Both short- and long-term fumigation produced similar plant-behaviour responses to the two SO 2 concentrations.