Responses to So 2 Pollution in 41 British Herbaceous Species

Abstract

1. Seedlings of 41 British herbaceous species of contrasting functional type were screened for sensitivity to SO 2 pollution in a large-scale 'Solardome' exposure facility. Sand was used as a growing medium and there was an ample supply of water and mineral nutrients. Plants were exposed continuously for 83 days to 100 nll -1 SO 2 (v/v in air), with a series of higher peaks of SO 2 concentration, the frequency and duration of which increased with time. 2. Exposure to SO 2 caused significant (P<0.05) reductions in the dry mass of whole plants, roots and shoots in the cases of 18, 19 and 12 of the species, respectively. Generally, the adverse effect on root growth was greater than the adverse effect on shoot growth. Total leaf area was reduced in seven species in response to SO 2 . 3. Significant correlations were found between per cent response to SO 2 exposure and C-S-R functional type. These were explicitly related to relative growth rate in the seedling phase, a predictor of stress-tolerance. Slow-growing, perennial species (stress tolerators), were less susceptible under exposure to SO 2 than were faster-growing, perennial species (competitors) or faster-growing, annual species (ruderals). 4. The general pattern of species responses to SO 2 was similar to that previously reported for O 3 fumigation but it contrasts markedly with that found among a similar range of species growing under elevated CO 2 .