Abstract
Ten conifer species were grown in an unshaded greenhouse at the University of Maryland under 3 levels of biologically effective ultraviolet‐B radiation. Ultraviolet‐B radiation was supplied by Westinghouse FS‐40 sunlamps and effective daily doses were 0, 12.4, and 19.1 kJ m–2. During the irradiation period, seedling growth and the development of stress symptoms were monitored. After 22 weeks of irradiation, seedlings were harvested and morphological characteristics analyzed. Visual symptoms included needle discoloration and stunting in three of the ten species tested. Seedling height was significantly reduced by supplemental UV‐B in Pinus contorta (lodgepole pine), Pinus resinosa (red pine), and Pinus taeda (loblolly pine). Biomass increased in Picea engelmannii (Engelmann spruce). Abies fraseri (Fraser fir), Pinus edulus (pinyon pine), and Pinus nigra (black pine) were unaffected by UV‐B while biomass reductions exceeding 5% were observed in all other species tested. These deleterious effects occurred despite the presence of morphological characteristics which would tend to reduce UV‐B effectiveness. Generally, the effects of supplemental UV‐B dose were less for those species native to higher elevations, implying the presence of natural adaptations to UV‐B.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
