Developmental and Structural Section
Lersten, Nels R. , Horner, Harry T. .
An overview of leaf crystal forms and macropattern diversity in Oleaceae.
The eudicot family Oleaceae (Lamiales), with 25 genera and 600 species of trees, shrubs and woody vines distributed in five tribes, occurs on all continents except Antarctica. Crystal macropatterns (types of crystals and their specific cell and tissue distribution in a leaf) are uncharted for Oleaceae, but scanty references, mostly to olive leaf (Olea europea),indicate unusual crystal forms occur. We are sampling 250 species from 23 genera, using bleached and cleared leaf samples from herbarium specimens, in order to provide a substantial survey of crystal macropatterns. When complete, it will provide results of interest both for systematics of family and for basic crystal biology. Our present incomplete results show remarkable diversity of both crystal types and macropatterns, some are described as follows. Tiny raphides (“slivers”), one to a few per cell, are unusual in angiosperms but are widespread in some Oleaceae tribes; in others, e.g. Jasmineae, exceedingly tiny sphaerites and druses (perhaps smallest known) are common, one per cell, which in some species occupy virtually every extra-vascular cell. In contrast, Fraxinus species commonly have large styloids (some of which are more-or-less flat plates) along all vascular bundles, and tiny single raphides in other cells. Tiny raphides or crystal sand arranged in a radiating circle from trichome bases are also unusual features. Tiny raphides, miniscule or sometimes larger prisms, sphaerites or druses, or mixtures of all these, are common in epidermis of many species, whereas most families have crystal-free foliar epidermi. In several Oleaceae species, crystals only occur in epidermis, while in other species crystals occur only in epidermis and along vascular bundles, with none in mesophyll. Also unusual is the absence of foliar crystals in parenchyma or sclerenchyma fibers within major vascular bundles of all species examined so far; all bundle-associated crystals occur instead only along periphery.
Log in to add this item to your schedule
1 - Iowa State University, Ecology, Evolution and Organismal Biology, 253 Bessey Hall, Ames, IA, 50011, USA
2 - Iowa State University, Genetics, Development and Cell Biology & Microscopy and NanoImaging Facility, Ames, IA, 50011-1020, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 8:30 AM