| Abstract Detail
Systematics Section/ASPT Sur, Gary [1], Adolf, Jason [2], Stacy, Elizabeth [3]. Variations in Leaf Micromorphology of Hawaiian Metrosideros Taxa. Studies of leaf micromorphology can be useful for uncovering cryptic variation among closely related plant taxa as well as for inferring ecological differences among taxa. The woody genus, Metrosideros, dominates Hawaii’s native vegetation, where its many forms occupy an expansive range of habitats. On the leeward ridges of Ko’olau Volcano, O’ahu, nine taxa of Metrosideros occur in a predictable sequence from low (dry) elevation to high (wet) elevation. We used scanning electron microscopy to examine the leaf micromorphology of these nine taxa (n=2 trees/taxon) with a follow-on study of stomatal complex (SC) length and density of the five glabrous taxa using nail-polish casts (n=10/taxon). SC densities were photographed at 100x magnification and SC lengths at 400x. Quartz Imaging PCI software and Microsoft Excel were used to measure the SC pixel-lengths and convert them into micrometers, respectively. Both SC density (p=0.000) and mean SC length (p=0.001) differed significantly across taxa. High-elevation, high-precipitation taxa had a higher density of smaller stomatal complexes compared to low-elevation, low-precipitation taxa and the steep windy slope-specialist, M. tremuloides. Thus, SC length and density appear to correlate with water availability/dessication stress in this group. Additionally, large, unidentified leaf structures were found in each of two unnamed taxa from high elevation. Outside of O’ahu, these structures, which may be oil glands, hydathodes, stomatal crypts, or domatia, were found in M. dieterii from Kaua’i only. Combined, the SC characters and presence of the unknown structures were sufficient to distinguish two of four unnamed varieties on O’ahu. Leaf micromorphology may therefore prove useful in distinguishing the many forms of hypervariable Metrosideros in Hawai’i. Log in to add this item to your schedule
1 - University of Hawaii at Hilo, 200 W. Kawili St., Hilo, HI, 96720, United States 2 - University of Hawaii at Hilo, Marine Science, 200 W. Kawili St., Hilo, HI, 96720, United States 3 - University Of Hawaii At Hilo, Department Of Biology, 200 West Kawili Street, Hilo, HI, 96720, USA
Keywords: Hawaiian Metrosideros leaf micromorphology taxonomy ecology Stomatal complex Stomatal density Stomatal length Hydathode Oil gland Unidentified structure Stomatal crypt Domatia.
Presentation Type: Oral Paper:Papers for Sections Session: 19 Location: Salon 9/The Shaw Conference Centre Date: Monday, July 27th, 2015 Time: 4:00 PM Number: 19010 Abstract ID:994 Candidate for Awards:None |