About Us | Help Videos | Contact Us | Subscriptions



This article in JEQ

  1. Vol. 23 No. 3, p. 613-621
    Received: July 6, 1993

    * Corresponding author(s):
Request Permissions


A White Clover System to Estimate Effects of Tropospheric Ozone on Plants

  1. Allen S. Heagle *,
  2. Joseph E. Miller and
  3. Dorothy E. Sherrill
  1. USDA-ARS Dep. of Plant Pathology, North Carolina State Univ., Raleigh, NC 27606;
    USDA-ARS, Dep. of Crop Science, North Carolina State Univ., Raleigh, NC 27606;
    Dep. of Plant Pathology, North Carolina State Univ., Raleigh, NC 27606.



An ozone-sensitive (NC-S) and an ozone-resistant (NC-R) clone of white clover (Trifolium repens L.) were tested to determine the feasibility of using them to indicate concentrations of tropospheric ozone (O3) and potential effects of O3 on plants. Plants of each clone were exposed daily in open-top field chambers to O3 concentrations ranging from 0.5 to 1.5 times the ambient concentrations for three summer seasons near Raleigh, NC. Foliar injury, foliar chlorophyll, and forage production of both clones were related directly to the O3 concentration. Ozone routinely injured leaves, suppressed foliar chlorophyll, and decreased growth of NC-S more than that of NC-R. Forage production was highly variable over a wide range of weather conditions, but the relative forage production rate of both clones under such conditions was similar and the seasonal O3 response relationship between NC-S and NC-R was relatively stable. The level of response of NC-S to O3 routinely increased from growth period to growth period suggesting an effect of previous exposure. More work is needed to calibrate the system over a wider range of ambient O3 levels and climatic conditions.

Cooperative investigations of the USDA-ARS and the North Carolina State Univ. Funded in part by the North Carolina Agric. Res. Service and the USEPA through Interagency Agreement no. DW123934170-6. The use of trade names in this publication does not imply endorsement by the North Carolina Agric. Res. Service or the USDA of the products named, nor criticism of similar ones not mentioned. This paper has not been subjected to USEPA peer review and should not be construed to represent the policy of the agency.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © .