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Title: A white clover system to estimate effects of tropospheric ozone on plants

Journal Article · · Journal of Environmental Quality
; ;  [1]
  1. North Carolina State Univ., Raleigh, NC (United States)

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 (O{sub 3}) and potential effects of O{sub 3} on plants. Plants of each clone were cloned daily in open-top field chambers to O{sub 3} 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 O{sub 3} 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 O{sub 3} response relationship between NC-S and NC-R was relatively stable. The level of response of NC-S to O{sub 3} 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 O{sub 3} levels and climatic conditions. 40 refs., 3 figs., 3 tabs.

Sponsoring Organization:
USDOE
OSTI ID:
245335
Journal Information:
Journal of Environmental Quality, Vol. 23, Issue 3; Other Information: PBD: May-Jun 1994
Country of Publication:
United States
Language:
English