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Main Title Effects of Ultravioloet-B Radiation on Photosynthesis of Different Aged Needles in Field-Grown Loblolly Pine.
Author Naidu, S. L. ; Sullivan, J. H. ; Teramura, A. H. ; DeLucia, E. H. ;
CORP Author Illinois Univ. at Urbana-Champaign. Dept. of Plant Biology. ;Maryland Univ., College Park. Dept. of Botany.;Corvallis Environmental Research Lab., OR.
Publisher c1993
Year Published 1993
Report Number EPA-R814017020; EPA/600/J-94/085;
Stock Number PB94-144730
Additional Subjects Ultraviolet radiation ; Photosynthesis ; Pine trees ; Air pollution ; Ozone ; Damage assessment ; Exposure ; Leaves(Botany) ; Age ; Carbon isotopes ; Nitrogen ; Plant growth ; Stratosphere ; Reprints ; Pinus taeda ; Loblolly pine trees ; Ultraviolet B radiation
Library Call Number Additional Info Location Last
NTIS  PB94-144730 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 14p
A continuing decline in stratospheric ozone concentrations caused by atmospheric pollutants has stimulated interest in consequences of increased penetration of ultraviolet-B radiation to the surface of the earth. The authors examined the effect of supplemental UV-B (290-320 nm) on photosynthetic characteristics of different aged needles of 3-year-old, field-grown loblolly pine (Pinus taeda L.). Needles in four age classes were examined: (1) most recently fully expanded, year 3; (2) first flush, year 3; (3) final flush, year 2; and (4) oldest needles still present, year 2. Enhanced UV-B radiation caused a statistically significant decrease (6%) in the ratio of variable to maximum fluorescence (F sub v)/(F sub m) following dark adaption only in needles from the youngest age class, suggesting transient damage to photosynthesis. Exposure to enhanced UV-B radiation caused a 20% decrease in total biomass and a 4% decrease in needle length of needles in age classes 1, 2, and 4, respectivly.