GAS EXCHANGE CHARACTERISTICS OF HETEROMELES ARBUTIFOLIA DURING FUMIGATION WITH SULPHUR DIOXIDE

Published

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

  • ATKINSON, CJ; WINNER, WE

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