VIEW ARTICLE

Physiology and Biochemistry

Chemical and Structural Characterization of the Needle Epicuticular Wax of Two Clones of Pinus strobus Differing in Sensitivity to Ozone. J. L. Trimble, Former graduate research assistant, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061, Present address of senior author: Science Applications, Inc., Suite 1000, Jackson Plaza Tower, 800 Oak Ridge Turnpike, Oak Ridge, TN 37830; J. M. Skelly(2), S. A. Tolin(3), and D. M. Orcutt(4). (2)(3)(4)Professor of Plant Pathology, associate professor of plant pathology, and associate professor of plant physiology, respectively, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg 24061. Phytopathology 72:652-656. Accepted for publication 9 September 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-652.

Two clones of eastern white pine (Pinus strobus), one sensitive and one tolerant to ozone (O₃), were exposed to 0.0 and 0.30 ppm O₃ for 6 hr/day for 7 consecutive days. Intact fascicles were excised from the terminal apex of each tree, and fine structure of the epicuticular wax was examined by scanning electron microscopy. All samples were characterized either by a fibrillar wax structure or an amorphous, platelike wax structure, regardless of O₃ exposure or previously determined O₃ sensitivity. Epicuticular wax removed from harvested fascicles was analyzed for alkane content by using gas-liquid chromatography. Hentriacontane (C₃₁) was the predominant alkane. Alkane concentration was significantly greater for the tolerant clone on both a fascicle surface area and fascicle weight basis, regardless of exposure to O₃.