Genetics, Development and Cell Biology Genetics, Development and Cell Biology Publications 9-2005 Macropattern of Styloid and Druse Crystals in Quillaja (Quillajaceae) Bark and Leaves Nels R. Lersten Iowa State University Harry T. Horner Iowa State University, [email protected] Follow this and additional works at: http://lib.dr.iastate.edu/gdcb_las_pubs Part of the Botany Commons, Other Ecology and Evolutionary Biology Commons, Plant Biology Commons, and the Plant Breeding and Genetics Commons The ompc lete bibliographic information for this item can be found at http://lib.dr.iastate.edu/ gdcb_las_pubs/43. For information on how to cite this item, please visit http://lib.dr.iastate.edu/ howtocite.html. This Article is brought to you for free and open access by the Genetics, Development and Cell Biology at Iowa State University Digital Repository. It has been accepted for inclusion in Genetics, Development and Cell Biology Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Macropattern of Styloid and Druse Crystals in Quillaja (Quillajaceae) Bark and Leaves Abstract Quillaja has been shuffled among tribes and subfamilies of Rosaceae, segregated from it as a separate family, and, most recently, transferred to the Fabales as a separate family. Many anomalous characters have kept it from being settled anywhere permanently. One character never mentioned by systematists, but long known, is the anomalous (for Rosaceae) occurrence of prominent styloid calcium oxalate crystals, reported from the inner bark of stems. We describe in more detail the macropattern of crystal distribution in stem and leaf, using vibratome sections, sodium hypochlorite clearings of leaves, and polarizing and scanning electron microscopy. Styloids are extremely numerous in the phloem of stems, and they continue in phloem of the short petiole and midrib bundle and in main lateral veins of the leaf lamina. Druses, never reported before, occur in cortex and pith of young stems (not seen in old stems) and are numerous in the spongy mesophyll, but not the palisade mesophyll, of the leaf lamina. Styloids occur in three of the four families of the newly constituted Fabales. Styloids in phloem, along with fiber strands, may provide a barrier to protect from bark borers and similar pests. Keywords bark, calcium oxalate, druses, leaf anatomy, phloem, Quillaja, Quillajaceae, styloids Disciplines Botany | Other Ecology and Evolutionary Biology | Plant Biology | Plant Breeding and Genetics Comments This article is from International Journal of Plant Sciences 166 (2005); 705, doi: 10.1086/430195. Posted with permission. This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/gdcb_las_pubs/43 Macropattern of Styloid and Druse Crystals in Quillaja (Quillajaceae) Bark and Leaves Author(s): Nels R. Lersten and Harry T. Horner Source: International Journal of Plant Sciences, Vol. 166, No. 5 (September 2005), pp. 705- 711 Published by: The University of Chicago Press Stable URL: http://www.jstor.org/stable/10.1086/430195 Accessed: 14-06-2016 14:24 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://about.jstor.org/terms JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to International Journal of Plant Sciences This content downloaded from 129.186.1.55 on Tue, 14 Jun 2016 14:24:54 UTC All use subject to http://about.jstor.org/terms Int. J. Plant Sci. 166(5):705–711. 2005. Ó 2005 by The University of Chicago. All rights reserved. 1058-5893/2005/16605-0002$15.00 MACROPATTERN OF STYLOID AND DRUSE CRYSTALS IN QUILLAJA (QUILLAJACEAE) BARK AND LEAVES Nels R. Lersten and Harry T. Horner1 Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011-1020, U.S.A.; and Department of Genetics, Development and Cell Biology, and Bessey Microscopy Facility, Iowa State University, Ames, Iowa 50011-1020, U.S.A. Quillaja has been shuffled among tribes and subfamilies of Rosaceae, segregated from it as a separate family, and, most recently, transferred to the Fabales as a separate family. Many anomalous characters have kept it from being settled anywhere permanently. One character never mentioned by systematists, but long known, is the anomalous (for Rosaceae) occurrence of prominent styloid calcium oxalate crystals, reported from the inner bark of stems. We describe in more detail the macropattern of crystal distribution in stem and leaf, using vibratome sections, sodium hypochlorite clearings of leaves, and polarizing and scanning electron microscopy. Styloids are extremely numerous in the phloem of stems, and they continue in phloem of the short petiole and midrib bundle and in main lateral veins of the leaf lamina. Druses, never reported before, occur in cortex and pith of young stems (not seen in old stems) and are numerous in the spongy mesophyll, but not the palisade mesophyll, of the leaf lamina. Styloids occur in three of the four families of the newly constituted Fabales. Styloids in phloem, along with fiber strands, may provide a barrier to protect from bark borers and similar pests. Keywords: bark, calcium oxalate, druses, leaf anatomy, phloem, Quillaja, Quillajaceae, styloids. Introduction Goldblatt (1976) determined chromosome numbers for the six genera often included in Quillajeae and found that the Quillaja Molina includes two South American species of two species of Quillaja, each with n ¼ 14, differed from the evergreen trees, Quillaja brasiliensis Martius and Quillaja other genera. Although Kageneckia has n ¼ 17, Goldblatt be- saponaria Molina. Quillaja saponaria is the soapbark tree of lieved that it had significant floral similarities to Quillaja and commerce, source of numerous industrial and pharmaceutical therefore concluded that the two genera ‘‘are perhaps best re- products derived from saponins extracted from its inner garded as constituting a distinct subfamily, developed collat- bark. erally with the Maloideae from an ancestral spiraeoidlike Quillaja was originally described in Rosaceae, but Don stock, and retaining many ancestral characteristics’’ (p. 206). (1831) segregated it, along with Kageneckia and Vauquelinia, Zhang (1992) surveyed wood anatomy of Rosaceae and as a separate family, Quillajaceae. Most systematists since reached a different conclusion. He stated that the Quillajoid then have still regarded Quillaja as a member of Rosaceae, genera collectively have ‘‘anatomically quite derived wood’’ but there has never been agreement as to its subfamilial and (p. 110) and suggested that they should be either included in tribal affiliation within this family. In recent decades, one to subfamily Prunoideae or placed next to it as a separate sub- five other genera of somewhat problematic status in the fam- family. ily have been allied with it to form the Quillajeae, a tribe Morgan et al. (1994) reviewed previous systematic treat- that is also of uncertain subfamily affiliation. Authors of ments of the Quillajoid genera and discussed their often three recent publications have reverted to the view that Quil- disparate morphological, cytological, and biochemical char- laja does not belong in Rosaceae. Some of the various sys- acteristics. They added original rbcL data to characteristics tematic opinions deserve mention. that other workers considered significant, concluding not Bate-Smith (1965) analyzed saponins of Quillaja and only that Quillajeae is an unnatural tribe but also that Quil- stated that their chemical components collectively represent laja does not even belong in Rosaceae. They did not assign ‘‘a feature so unusual in Rosaceae that this alone might sug- Quillaja to any other family, but they suggested Fabaceae, gest an isolated position for it in the taxonomy of the family’’ Polygalaceae, and genus Stylobasium within Surianaceae as (p. 538). He concluded that Quillaja is relatively primitive possibilities. Thorne (2001) accepted one of the nonrosa- in Rosaceae and interpreted the Quillajeae as consisting of ceous suggestions of Morgan et al. (1994) and transferred three genera: Quillaja, Kageneckia, and Vauquelinia. Quillaja to Fabaceae but provided no evidence for this deci- sion. Most recently, the family Quillajaceae, including only Quillaja, has been resurrected, and, similar to the views of 1 E-mail [email protected]. Morgan et al. (1994) and Thorne (2001), it has been joined Manuscript received December 2004; revised manuscript received March with the Surianaceae, Polygalaceae, and Fabaceae to form an 2005. expanded order Fabales (Judd and Olmstead 2004). 705 This content downloaded from 129.186.1.55 on Tue, 14 Jun 2016 14:24:54 UTC All use subject to http://about.jstor.org/terms 706 INTERNATIONAL JOURNAL OF PLANT SCIENCES These diverse opinions concerning Quillaja’s classification tioned preparations were observed under bright-field optics, indicate a need for new characters. It is surprising, therefore, with or without crossed polarizers, and images were pro- that no systematist has mentioned its conspicuous styloids, cessed as mentioned by