Effects of Sulphur Dioxide and Nitrogen Dioxide on Growth and Translocation in Winter Wheat

Abstract

Gould, R. P. and Mansfield, T. A. 1988. Effects of sulphur dioxide and nitrogen dioxide on growth and translocation in winter wheat. —J. exp. Bot 39: 389–99 Winter wheat (Triticum aestivum L. cv. Avalon) was grown under simulated autumn conditions for 4 weeks and exposed to a mixture of SO₂ and NO₂. Biomass was measured after 2, 3 and 4 weeks and the flag leaves of sample plants were labelled with ¹⁴CO₂. Biomass yields revealed an increase in shoot-to-root ratios under polluted conditions. The labelling experiments showed that less assimilate was transported to the roots, whilst more was allocated to the younger components of the plant. It appeared that NO₂ and SO₂ also caused labelled photosynthate to be retained in the labelled leaf. Reducing the photon flux exacerbated the effects of SO₂ and NO₂ as indicated by changes in biomass and by the distribution of ¹⁴C.