Journal Article

The objectives of this study were to determine the gas exchange responses of Heteromeles arbutifolia (Ait.) Roem. to a range of sulphur dioxide (SO 2 ) concentrations applied in various sequences including possible ambient levels. Carbon dioxide and light‐response curves were used to determine the mechanisms of SO 2 responses. These experiments were performed with greenhouse‐grown plants. Net photosynthesis A of H. arbutifolia was shown to be depressed by SO 2 concentrations ranging from 1.5 to 43.8 μmol m −3 (0.04 to 1 μl l −1 ). In most cases on first exposure to SO 2 a larger decrease in stomatal conductance to water vapour (g H ) occurred than on subsequent exposures to either the same or greater SO 2 concentrations. Acclimation of g H to SO 2 appeared to occur with repeated exposure. Light‐response curves determined during exposure to 25 μmol SO 2 m −3 (0.6 μl l −1 ) for a leaf repeatedly exposed to SO 2 indicated that inefficiency of photon utilization in the primary reaction of energy transduction or reduction in photosynthetic capacity was unlikely. The maximum rates of A (A max ) determined from these curves were similar in both SO 2 and SO 2− free air. The limitations of g H to carbon acquisition were removed using CO 2− response curves [photosynthesis expressed relative to the internal CO 2 concentration (C i )]. This analysis shows that A may have been limited during repeated exposures by reduced carboxylation efficiency. It appeared that at similar values of g H , plants exposed to SO 2 would fix less carbon and water use efficiency (WUE) would decrease in polluted plants. Copyright © 1987, Wiley Blackwell. All rights reserved

Full Text

Duke Authors

Cited Authors


Published Date

  • January 1, 1987

Published In

Volume / Issue

  • 106 / 3

Start / End Page

  • 423 - 436

Electronic International Standard Serial Number (EISSN)

  • 1469-8137

International Standard Serial Number (ISSN)

  • 0028-646X

Digital Object Identifier (DOI)

  • 10.1111/j.1469-8137.1987.tb00150.x

Citation Source

  • Scopus