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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.

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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

Hawaiian Metrosideros
leaf micromorphology
Stomatal complex
Stomatal density
Stomatal length
Oil gland
Unidentified structure
Stomatal crypt

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

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