A distinctive seed coat pattern, which contrasts with that of about 200 other genera of papilionoid legumes, is evident in 47 species of 4 genera of tribe Vicieae. A conspicuous papillose pattern, seen at magnifications of 50X or higher, is caused by protrusions from the tips of malpighian cells of the epidermis. The hilar rim is quite reduced, a rare feature elsewhere in the subfamily. These two characters, and the elongate hilum noted by others, strengthen the definition of this tribe

Lersten, Nels R.

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A Distinctive Seed Coat Pattern in the Vicieae (Papilionoideae; Leguminosae)

University of Northern Iowa

Proceedings of the Iowa Academy of Science Volume 86 Number Article 5 1979 A Distinctive Seed Coat Pattern in the Vicieae (Papilionoideae; Leguminosae) Nels R. Lersten Iowa State University Let us know how access to this document benefits you Copyright ©1979 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Lersten, Nels R. (1979) "A Distinctive Seed Coat Pattern in the Vicieae (Papilionoideae; Leguminosae)," Proceedings of the Iowa Academy of Science, 86(3), 102-104. Available at: https://scholarworks.uni.edu/pias/vol86/iss3/5 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. Proc. Iowa Acad. Sci. 86(3):102-104. 1979 A Distinctive Seed Coat Pattern in the Vicieae (Papilionoideae; Leguminosae) NELS R. LERSTEN Department of Botany, Iowa State University, Ames, Iowa 50011 A distinctive seed coat pattern, which contrasts with that of about 200 other genera of papilionoid legumes, is evident in 47 species of 4 genera of tribe Vicieae. A conspicuous papillose pattern, seen at magnifications of SOX or higher, is caused by protrusions from the tips of malpighian cells of the epidermis. The hilar rim is quite reduced, a rare feature elsewhere in the subfamily. These two characters, and the elongate hilum noted by others, strengthen the definition of this tribe. INDEX DESCRIPTORS: Leguminosae, Papilionoideae, Vicieae, seed coat anatomy, papillose seed coat. Seeds of most Leguminosae are smooth and featureless at low magnification. Topography of the seed surface has, therefore, been ignored in past taxonomic studies. Scanning electron microscopy (SEM), however, has revealed new features. Brisson and Peterson ( 1976) reported that only 9 published studies of legume seeds contained SEM photos, and none of them concerned taxonomy. Since Brisson and Peterson's review, some taxonomic work using SEM has been published. Heyn and Herrnstadt ( 1977) used SEM to reveal some differences in surface patterns of Lupinus seeds that proved to be of taxonomic significance. Newell and Hymowitz (1978) examined seeds of Glycine subg. Glycine of the Phaseoleae by SEM and concluded that surface patterns, particularly of the perisperm (inner pod wall remnants which adhere to the seed), provided useful taxonomic characters. Also in Phaseoleae, Sharma et al (1977) used SEM of seed coat patterns to attempt to distinguish taxa in a species complex within Phaseolus. La Sota' s unpublished dissertation ( 1978) and earlier work by Gutterman and Heydecker ( 1973) show that surface features of Ononis seeds seen by SEM are clearly of taxonomic value. Gunn and La Sota (1978) included a key to 5 Ononis species based on SEM characters. Polhill (1976) used both light microscopy and SEM to show that distinctive seed coat patterns may occur in certain groups of genera within the tribe Genisteae. I am conducting a survey of seed coat anatomy in the legume subfamily Papilionoideae, which includes about 440 genera and 12,000 species. Among approximately 200 genera I have examined to date, representing all but one of the tribes, the singular papillose pattern in the tribe Vicieae differs strikingly from all others encountered. A preliminary report on this previously undescribed seed coat pattern is presented here. MATERIALS AND METHODS This report is based on observations of seeds of representatives of 4 of the 5 genera currently recognized in the Vicieae: Pisum sativum, Lens culinaris, 19 species of Lathyrus, and 26 species of Vicia. The names of the species will be included in a later report. Seeds of the monotypic Vavilovia were not available. Seeds were obtained from the U.S. National Seed Herbarium of the U.S. Department of Agriculture, Beltsville, MD, and secondarily from European botanical gardens and the Seed Testing Laboratory of Iowa State University. Whole seeds, or portions of seeds, were dipped in absolute ethanol and mounted in silver paste on standard brass discs. The specimens were coated with carbon and gold in a vacuum evaporator and viewed in a JEOL JSM-35 scanning electron microscope. Photographs were taken with Polaroid type 665 film. RESULTS AND DISCUSSION Kupicha (1977) described seeds of the Vicieae as generally spherical or oblong, with a more or less linear hilum. She did not mention that the hilar rim is quite reduced, a feature I have not seen in other tribes. Figure l illustrates these features, as well as the often elongate micro-pyle. The papillose topography can also be discerned even at this rather low magnification. At higher magnification (Fig. 2), the papillose pattern shows clearly. The abrupt boundary between hilum and adja-cent seed coat is also apparent. As in other tribes, the micropyle in mature seeds is closed and covered with a cuticle. Figures 3, 4 show the seed coat in detail. The papillae are seen to be domed protrusions from the tip of individual malpighian cells. The almost complete lack of a hilar rim is also evident (Fig. 3). The papillose pattern was evident in all species examined, e.g. Vicia, Fig. 1-4;Lathyrus, Fig. 5;Pisum, Fig. 6. Seeds of Lens (not illustrated) are similar. Marbach and Mayer (1974) showed an identical pattern in Pisum elatius but made no comment about it. In seeds sectioned with a razor blade, coated, and viewed by SEM, the palisadelike malpighian layer characteristic of all papilionoid tribes can be seen (Fig. 7). Figure 8 shows the tips of some malpighian cells in detail. Because seeds shrink during maturation and drying, the malpighian cells become compressed, and only a vertical line is left to suggest the lumen. The elongate hilum, reduced hilar rim, and especially the papillose surface caused by protrusion of individual malpighian cells, appears to form a trio of seed characters that help to define the tribe Vicieae. None of these features is present in seeds of Abrus, a genus once placed in Vicieae, or in Cicer (Lersten, unpublished), a genus excluded from the Vicieae by Kupicha (1977). My observations on 47 species support Kupicha's delimitation of the tribe. A more comprehensive study is in preparation by Lersten and Fig. 1-8. SEM views of the seed coat of members of the Vicieae. Fig. l. Vicia pannonica. Note the elongate hilum, greatly reduced hilar rim, and elongate micropyle (upper left). Papi/lose seed coat is barely visible. X48. Fig. 2. Vicia sativa. Micropyle, part of hilum, and adjacent seed coat. Papi/lose seed coat is apparent. X200. Fig. 3. Vicia pannonica. Papillae of seed coat are clearly visible at high magnification. Seed coat abuts abruptly on hilum at top with hilar rim virtually lacking. XJOOO. Fig. 4. Vicia atropurpureus. Highly magnified view of papillae, each of which is protruding tip of an epidermal cell. Note ridged cuticle between but not on the papillae. X6000. Fig. 5. Lathyrus hirsutus. Papillose pattern as in Vicia. Hilar rim is reduced but evident (arrow). X480. Fig. 6. Pisum sativum. Papi/lose seed coat as in Vicia and Lathyrus. XJOOO. 1Lersten: A Distinctive Seed Coat Pattern in the Vicieae (Papilionoideae; LPublished by UNI ScholarWorks, 1979SEED COAT PATTERN IN VICIEAE 103 2Proceedings of the Iowa Academy of Science, Vol. 86 [1979], No. 3, Art. 5https://scholarworks.uni.edu/pias/vol86/iss3/5104 PROC. IOWA SCI. 86 (1979) Fig. 7. SEM of sectioned seed coat of Lathyrus latifolius. Elongate epidermal ( malpighian) cells each end in a rounded papilla. X660. Fig. 8. Enlargement of part of Fig . 7 to show detail. Arrow indicates reduced cell lumen in papillose cell that is probably in median longitudinal view. X2000 . Gunn, which will deal with seeds of Vicieae and their bearing on taxonomic relations and evolution of this tribe . ACKNOWLEDGMENTS I thank Dr. Charles R. Gunn, Curator of Seeds, U.S .D.A., for providing seeds and advice . This work was supported by National Science Foundation Grant DEB-78-04-296 and was carried out in the Bessey Microscopy Facility of Iowa State University . REFERENCES BRISSON, J.D., and R.L. PETERSON. 1976. A critical review of the use of scanning electron microscopy in the study of the seed coat. p. 477-496. In Scanning Electron Microscopy/1976 (Part VII), Vol. II, Proceedings of the Works.hop on Plant Science Applications of the SEM. Ill. Inst . Technol. Res. Inst., Chicago, Ill. GUNN, C.R., and L.R. LaSOTA. 1978. Automated identification of true and surrogate seeds. p. 241-256. /n J.A. Romberger, R.H. Foote, L. Knudson, and P.L. Lentz (ed.). Beltsville Symposia in Agricultural Research II. Biosystematics and Agriculture. Allan Held, Osmun and Co ., Montclair, N.J . GUTTERMAN, Y., and W. HEYDECKER. 1973 . Studies of the surfaces of desert plant seeds. I. Effect of day length upon maturation of the seed coat of Ononis sicu/a Guss. Ann . Bot. 37:1049-1050. HEYN, C.C ., and I. HERRNSTADT. 1977. Seed coat structure of Old World Lupinus species. Bot. Not. 130:427-436. KUPICHA, F.K. 1977. The delimitation of the tribe Vicieae (Leguminosae) and the relationships ofCicer L. Bot. J . Linn. Soc. 74:131-162. LaSOTA, L.R. 1978. Comparative testa morphology of the genus Ononis (Leguminosae). Ph.D. dissertation, Univ. of Maryland, College Park. MARBACH, I., andA.M. MAYER. 1974. Permeabilityofseedcoatstowater as related to drying conditions and metabolism of phenolics . Plant Physiol. 54:817-820. NEWELL, C.A., and T. HYMOWITZ. 1978. Seed coat variation in Glycine Willd. subgenus Glycine (Leguminosae) by SEM. Brittonia 30:76-88. POLHILL, R.M. 1976. Genisteae (Adans.) Benth. and related tribes (Legumi-nosae) . Bot. Syst. 1: 143-368. SHARMA, S.K., C.R . BABU, B.M. JOHRI, and A. HEPWORTH. 1977. SEM studies on seed coat patterns in Phaseolus mungo - radiatus -sublobatus complex. Phytomorphology 27: 106-111. 3Lersten: A Distinctive Seed Coat Pattern in the Vicieae (Papilionoideae; LPublished by UNI ScholarWorks, 1979

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A Distinctive Seed Coat Pattern in the Vicieae (Papilionoideae; Leguminosae)

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