title: Growth response of loblolly pine (Pinus taeda L.) seedlings to ozone fumigation.
abstract: Twenty-two week-old Pinus taeda L. (loblolly pine) seedlings of 30 open-pollinated and five full-sib families, representing a wide range in geographic origin, were grown in charcoal-filtered (CF) air or CF-air supplemented with 160 or 320 nl liter(-1) ozone for 8 h day(-1), 4 days week(-1), for 9 weeks. Visible foliar injury (banded chlorosis, tip burn and premature senescence) was apparent in many families after 3 weeks in 320 nl liter(-1) and 6 weeks in 160 nl liter(-1) ozone. Decreases in relative height and root collar diameter growth rates, total dry weight, root dry weight, shoot dry weight, and root/shoot ratios were evident after 9 weeks of treatment with both 160 and 320 nl liter(-1) ozone. For relative height growth rates, family differences in response to ozone were observed. By the study's end, net photosynthesis rates were 15% less for the 320 nl liter(-1) ozone treatment as compared to the CF-air treatment. Total soluble sugar and total starch content of roots were not changed after 9 weeks of ozone exposure.
authors.affiliation: School of Forest Resources, University of Georgia, Athens, GA 30602, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Wiselogel
authors.forename: J K
authors.initials: JK
authors.lastname: Bailey
authors.forename: R J
authors.initials: RJ
authors.lastname: Newton
authors.forename: F
authors.initials: F
authors.lastname: Fong