In:
New Phytologist, Wiley, Vol. 123, No. 4 ( 1993-01), p. 751-762
Abstract:
The effects of mixtures of ozone and carbon dioxide on growth and physiology of an O 3 ‐sensitive (NC‐S) and an O 3 ‐resistant (NC‐R) clone of white clover (Trifolium repens L.) were determined. The experiment was performed in a greenhouse with O 3 treatments of 5 and 82 nl l −1 (ppb) for 6 h d −1 and CO 2 treatments of 380 (ambient), 490,600, and 710 μl l −1 (ppm) for 24 h d −1 . Enrichment with CO 2 decreased foliar gas exchange (measured as stomatal resistance) of NC‐R more than that of NC‐S whereas O 3 decreased gas exchange of NC‐S more than that of NC‐R. Ozone caused extensive foliar injury of NC‐S but caused only slight injury of NC‐R. CO 2 enrichment suppressed O 3 ‐induced foliar injury of NC‐S as measured after 4 wk of exposure, but this effect diminished after 8 wk of exposure. CO 2 enrichment decreased the relative chlorophyll content (μg of chlorophyll mg −1 of leaf tissue sampled) but not the total chlorophyll (total chlorophyll in the leaves sampled). There were no O 3 × CO 2 interactions for foliar chlorophyll. High concentrations of CO 2 caused reddening of new leaves near the end of the 8 wk exposure period. CO 2 enrichment decreased foliar concentrations of N, P, K, S, Cu, B, and Fe, increased foliar concentrations of Mn, but did not affect Zn, Ca, or Mg. Ozone exposure did not modify the CO 2 effects on foliar nutrient concentration. Ozone decreased growth of NC‐S but not NC‐R while CO 2 enrichment stimulated growth of both clones. The highest CO 2 concentration appeared to decrease the effects of O 3 on growth of NC‐S. However, except for a transitory effect on foliar injury, there was no evidence that CO 2 , at concentrations less than the highest used in this study, will protect white clover from the effects of tropospheric O 3 .
Type of Medium:
Online Resource
ISSN:
0028-646X
,
1469-8137
DOI:
10.1111/nph.1993.123.issue-4
DOI:
10.1111/j.1469-8137.1993.tb03786.x
Language:
English
Publisher:
Wiley
Publication Date:
1993
detail.hit.zdb_id:
208885-X
detail.hit.zdb_id:
1472194-6
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