Journal of Advances in Biology & Biotechnology Volume 25, Issue 11-12, Page 48-54, 2022; Article no.JABB.96922 ISSN: 2394-1081 Taxonomic Significance of Foliar and Stem Anatomy in the Delimitation of Piptadeniastrum africanum (Hook.F.) Brenan and Cathormion altissimum (Hook.F.) Hutch. & Dandy Felix Okponanabofa Youkparigha a, Bio Louis Nyananyo b and Glory Richard c* a Department of Biological Sciences, Faculty of Science, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria. b Department of Plant Science and Biotechnology, Faculty of Science, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria. c Department of Community Medicine, Faculty of Clinical Sciences, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria. Authors’ contributions This work was carried out in collaboration among all authors. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JABB/2022/v25i11-12609 Open Peer Review History: This journal follows the Advanced Open Peer Review policy. Identity of the Reviewers, Editor(s) and additional Reviewers, peer review comments, different versions of the manuscript, comments of the editors, etc., are available here: https://www.sdiarticle5.com/review-history/96922 Original Research Article Received: 20/10/2022 Accepted: 29/12/2022 Published: 31/12/2022 ABSTRACT The current monotypic status of the genus Piptadeniastrum Brenan is reasonably challenged as Cathormion altissimum is claimed to be closely related to Piptadeniastrum africanum – the only species in the genus – by some indigenous people of Bayelsa State. This work systematically _____________________________________________________________________________________________________ *Corresponding author: E-mail: richieglo63@gmail.com; J. Adv. Biol. Biotechnol., vol. 25, no. 11-12, pp. 48-54, 2022 Youkparigha et al.; J. Adv. Biol. Biotechnol., vol. 25, no. 11-12, pp. 48-54, 2022; Article no.JABB.96922 examines this claim by studying some aspects of the foliar and stem anatomy of P. africanum and C. altissimum. Leaf peels and stem sections were made and analyzed according to standard procedures. Anatomical characteristics considered include stomata distribution, stomatal Index, type of stomata, the shape of leaf epidermal cells and anticlinal walls, the outline of the stem, and the arrangement of vascular bundles. Results showed that stomatal distribution in both plants was hypostomatic. Stomatal index and stomata type was 21.5% and mainly anomocytic, respectively, for P. africanum and 14.4% and primarily paracytic, respectively, for C. altissimum. Epidermal cell shape is irregular with undulating anticlinal walls in P. africanum, while epidermal cell shape is rectangular to polygonal with curved or straight anticlinal walls in C. altissimum. The outline of the stem is angular with four pronounced ridges and furrows in P. africanum, while the stem outline is wavy with very mild protrusions in C. altissimum. The differences in anatomical characteristics may justify the placement of these plants in different genera. Piptadeniastrum Brenan is monotypic. Keywords: Piptadeniastrum africanum; Cathormion altissimum; anatomical character; anticlinal walls; paracytic; hypostomatic; stomatal index. they occur in the wild. A survey in the study area showed that one of the trees closely related to P. africanum is C. altissimum [10]. Also of the Fabaceae family, C. altissimum is of great ethnobotanical importance. It is used as food spice [11], medicine [12,13], and wood of choice for caving durable, quality kitchen utensils like mortar, pestle, and spatula that are indispensable in a typical Niger Delta family. These carved utensils are valuable traditional gifts to new couples during marriage ceremonies. 1. INTRODUCTION The species P. africanum is a forest tree of the rain forest, published and widely accepted as the only species in the genus Piptadeniastrum Brenan, a genus that belongs to the family Fabaceae Lindsl, Subfamily Mimosoideae [1-3]. P. africanum (Hook.f.) Brenan is endemic to tropical Africa and occurs in the Niger Delta, especially on riverbanks in the riverine areas of the rainforest [4-6]. This forest tree is of great interest due to its wide range of ethnobotanical uses – medicinal, domestic, social, and agricultural applications. Thus, studies have concentrated on its chemical constituents and their usefulness to man. Consequently, comparatively few taxonomic studies focus on clearing the doubts that surround its monotypic taxonomic status. This research gap is evident because names such as Piptadeniastrum manni Oliver, with an unresolved status and low confidence level, were placed in the Plant List [7] and later placed with an accepted status and medium confidence level [8] but placed as a species of the genus Piptadeniastrum Brenan in TROPICOS [9]. Moreover, reports of varieties of P. africanum, such as Piptadeniastrum africanum var. africanum and Piptadeniastrum africanum var. brachysperma Pellergr are cited in the literature [8]. Observation is a critical element of the scientific method. The indigenous people, who are close to the forest and have depended on it for their sustenance over the years, have significant ethnobotanical knowledge about these trees, and the importance of applying appropriate scientific methods to study their observations must be emphasized. Indigenous knowledge, sometimes called Traditional Ecological Knowledge (TEK), and its immense contribution to discoveries in natural sciences and medically valuable substances in plants cannot be controverted [1416]. Moreover, when the identity of even a single plant is not sure and authentic from broad-based, empirical taxonomic evidence, then extant erroneous phylogeny in the relevant taxa is undeniable. This study, therefore, is aimed at describing some leaf epidermal and stem anatomical characteristics that may be significant, at least in serving as supportive taxonomic evidence, in the description and delimitation of P. africanum and C. altissimum as either belonging to different genera (as they are present) or the possibility of belonging to the same genus and thus establishing their degree of relatedness. Similarly, the identification, nomenclature, and taxonomic status of this species (whether it is the only species in the genus Piptadeniastrum Brenan) among some indigenous people in Bayelsa State is unclear. While most of the local people confidently affirm that there are two types of plants, they disagree on the forms in which 49 Youkparigha et al.; J. Adv. Biol. Biotechnol., vol. 25, no. 11-12, pp. 48-54, 2022; Article no.JABB.96922 2. MATERIALS AND METHODS 2.2 Sample Collection and Identification 2.1 Study Area Matured samples of the plants (Fig. 2) were collected from the study area and identified at the Forest Herbarium Ibadan of the Forestry Research Institute of Nigeria (FRIN). Voucher specimens of the plants – P. africanum (FHI 110137) and C. altissimum (110884) – were deposited in the herbarium for reference and further studies. Bayelsa State, where this study was carried out, comprises eight Local Government Areas (Fig. 0 1). The state is located within latitudes 04 15’ 0 0 North and 05 23’ south and longitudes 05 22’ 0 West and 06 45’ East. Delta State bounds it on the North, Rivers State on the East, and on the west and south by the Atlantic Ocean (Fig. 1). Fig. 1. Bayelsa State, showing the Local Government Areas (Inset: Map of Nigeria showing Study Area) Fig. 2. (a-b): (a) C. altissimum (b) P. africanum 50 Youkparigha et al.; J. Adv. Biol. Biotechnol., vol. 25, no. 11-12, pp. 48-54, 2022; Article no.JABB.96922 Cuttings from identical regions were made from fresh leaves of the plants collected from the field. Peels from the adaxial and abaxial surfaces of the leaves were obtained carefully with the aid of pins and forceps. Samples were stained with alcian blue or 1% safranin, rinsed in distilled water to remove excess stain, and mounted on microscope slides with a drop of glycerol. Epidermal features such as the shape of epidermal cells, type of anticlinal wall, stomatal distribution, stomata type, and stomatal index were studied. Stomatal index (SI) was estimated as reported by Obembe [17], while the terminology for stomata type was taken after Metcalfe and Chalk [18]. formaldehyde, 1 part of acetic acid, 18 parts of 70% ethanol) for at least 48 hours. Then, samples were washed with several changes of distilled water, dehydrated through 2-hour incubations in graded alcohol solutions (30%, 50%, 70%, and 100%) at room temperature, and embedded in wax. Hand or hard sections were cut with blades. Thin sections were selected and dewaxed by passing the specimens through a series of 3 hours of incubations in graded ethanol: chloroform solutions (1:3, 1:1, and 3:1), with a final 3-hour incubation in absolute ethanol. Samples were stained with alcian blue, counterstained with 1% safranin, and mounted on microscope slides. Photomicrographs were acquired with a digital camera. 2.4 Stem Anatomical Studies 3. RESULTS Matured plants from fresh vegetation were used for this study. Cut sections of the stem were fixed 0 0 at room temperature (23 C – 28 C) in Formaldehyde-acetic acid- alcohol (1 part of 40% 3.1 Leaf Epidermal Studies 2.3 Leaf Epidermal Studies Results of the leaf epidermal studies of the plants are presented in Table 1 and Fig. 3. Fig. 3. Adaxial and Abaxial leave epidermis of P. africanum and C. altissimum 51 Youkparigha et al.; J. Adv. Biol. Biotechnol., vol. 25, no. 11-12, pp. 48-54, 2022; Article no.JABB.96922 Table 1. Leaf epidermal characteristics of P. africanum and C. altissimum Characters/ Species P. africanum Stomatal Index (%) 21.5 C. altissimum 14.4 Stomata Type Mainly anomocytic Mainly paracytic Stomata distribution Hypostomatic Epidermal cell shape Irregular Anticlinal wall Undulating Hypostomatic Rectangular/ polygonal Curved/ straight Fig. 4. Cross-section of stems of P. africanum and C. altissimum and outline in different plants, they are affected by environmental factors. Consequently, the shape of epidermal cells should be helpful as confirmatory evidence [18]. However, variations in leaf epidermal characters have been used in the identification and classification of several plant groups because they are primarily controlled by genes and are structurally diverse [19-22]. Nurul-Aini et al. [23] showed that leaf micromorphological features such as stomata characteristics and the presence of trichomes were taxonomically significant in some selected taxa of Acanthaceae. Researchers have found leaf epidermal micromorphological features such as differences in epidermal cell shape and size and the stomatal index, and the pattern of anticlinal walls of epidermal cells to be of taxonomic significance among 43 species of Allium [24]. Reports show that the pattern of the anticlinal walls of epidermal cells was consistent within a species, but there were differences between species. Consequently, micromorphological characteristics of the epidermis of P. africanum and C. altissimum in 3.2 Stem Anatomical Studies Result of anatomical studies of the stems of P. africanum and C. altissimum is shown in Fig. 4. 4. DISCUSSION Stomatal distribution in both the leaves of P. africanum and C. altissimum is Hypostomatic i.e. stomata are found only on the abaxial surfaces of the leaves. The epidermal cell shape is irregular with undulating anticlinal walls in P. africanum, while the epidermal cell shape for C. altissimum is rectangular/polygonal with curved/straight anticlinal walls. The stomatal index is 21.5% in P. africanum with mainly anomocytic stomata type, while the stomatal Index for C. altissimum is 14.4% with mainly paracytic stomata. The taxonomical value of foliar epidermal characters such as hairs, stomata, and epidermal cells has been well established. Though epidermal cells vary considerably in size, shape, 52 Youkparigha et al.; J. Adv. Biol. Biotechnol., vol. 25, no. 11-12, pp. 48-54, 2022; Article no.JABB.96922 2. this study were of taxonomic significance in their delimitation into different genera. The stem of P. africanum has an angular outline with four pronounced ridges and furrows, while the stem of C. altissimum has a wavy outline. Furthermore, although the vascular bundles of both plants are scattered in the ground tissue, they differ in the patterns of grouping and arrangement. In C. altissimum, the vascular bundles are arranged in groups of about five, while in P. africanum, vascular bundles are concentrated at the ridges or protrusions. These anatomical characteristics may be significant in the delimitation of these plants. 3. 4. 5. 6. The significance of using stem anatomical features in collaboration with other lines of evidence in taxonomy is well known [25-29]. Cavente et al. [30] worked on six species of Rhipsalis and found that features of the stem anatomy discriminate between the species. Furthermore, Kaplan & Symoens [31] used stem anatomy to distinguish between two confusing African taxa (Potamogeten schweinfurthii and Potamogeten richardii). 7. 8. 9. 5. CONCLUSION 10. The results of the studies showed no sufficient degree of relationship that could warrant the placement of C. altissimum under the genus Piptadeniastrum Brenan. Consequently, the current monotypic status of the genus Piptadeniastrum Brenan is maintained. 11. 6. SIGNIFICANCE STATEMENT The nomenclatural conflict between P. africanum and C. altissimum, arising from the similar morphology of the leaves, was systematically resolved using evidence from foliar and stem anatomy. Furthermore, the information from the results of this study has enriched the existing literature on the taxonomy of plants. 12. COMPETING INTERESTS 13. The authors have declared that no competing interests exist. REFERENCES 1. Airy Shaw HK. J.C. Willis: A dictionary of flowering plants and ferns 8th ed. Revised. Cambridge: Cambridge University Press; 1985. 14. 53 Brusotti G, Tosi S, Tava A, Picco AM, Grisoli P, Cesari I, Caccialanza G. Antimicrobial and phytochemical properties of stem bark extracts from Piptadeniastrum africanum (Hook f.) Brenan. Industrial Crops and Products. 2013; 43:612-616 Gunn CR. Fruits and Seeds of Genera in the Subfamily Mimosoideae (Fabaceae). US Department of Agriculture, Technical Bulletin. 1984;1681 Brenan JPM. Piptadeniastrum africanum. Kew Bull. 1955; 179. Hutchinson J, Dalziel JM. Flora of West Tropical Africa. (2nd ed.). Vol. 1, Part 2. Revised by Keay RWJ; 1958. Nyananyo BL. Plants from the Niger Delta. Nigeria; 2006 The Plant List. Piptadeniastrum.2010; Accessed 19 May 2013. Available: https://www.theplantlist .org/ The Plant List. Piptadeniastrum. 2013; Accessed 19 May 2013. Available: https://www.theplantlist.org/ TROPICOS. Piptadeniastrum manni Oliv.2013; Missouri Botanical Garden. Accessed 19 May 2013. Available:fromhttps://www.tropicos.org/Na me/13069459. Youkparigha FO, Nyananyo BL, Oyedeji AA. Morphology and Distribution of Piptadeniastrum africanum (Hook.f.) Brenan and Cathormion altissimum (Hook.f.) Hutch. & Dandy in Bayelsa State, Nigeria. International Journal of Advanced Research in Botany. 2019; 5(2): 8-14. Jolaoso AA, Ajayi JO, Ogunmuyiwa JO, Albert OM. Changes in Functional Properties as a Measure of Biochemical Deterioration of Oso (fermented seeds of Cathormion altissimum). Journal of Emerging Trends in Engineering and Applied Sciences. 2012;3(4):608-613. Burkill HM. The useful plants of West Tropical Africa. Edn. Families J-l. Royal Botanic Gardens, Kew, Richmond, Surrey, England. 1985;2(3). Lemmens RHMJ. Albizia altissima Hook. f. Record for PROTA4U. Louppe, D. OtengAmoako, A.A. and Brink, M. (Editors). PROTA (Plant Resources for Tropical Africa), Waganengen, Netherlands; 2006. Available:https://www.prota4u.org/search.a sp. Brush SB. Indigenous knowledge of biological resources and Intellectual Property Rights: The role of Anthropology. Youkparigha et al.; J. Adv. Biol. Biotechnol., vol. 25, no. 11-12, pp. 48-54, 2022; Article no.JABB.96922 American Anthropologist. 1993;95(3):653- 24. Chen-Yi L Dun-Yan T. The taxonomic significance of leaf epidermal 671 micromorphological characters in 15. Reyes-Garcia V. The relevance of distinguishing 43 species of Allium l. traditional knowledge systems for (Amaryllidaceae) from Central Asia. ethnopharmacological research: theoretical Pakistan Journal of Botany. 2015;47(5): and methodological contributions. Journal 1979-1988. of Ethnobiology and Ethnomedicine. 2010; 6: 32 25. Wiegleb G.The importance of stem 16. Popp J. How Indigenous knowledge anatomical characters for systematics of advances modern science and technology. genus Potamogeton L. Flora. 1990; 184: The Conversation.2018. Accessed 18 April 197-208. 2020. 26. Metcalfe CR. On the taxonomic value of Available:https://theconversation.com/howthe anatomical structure of the vegetative indigenous-knowledge-advances-modernorgans of the dicotyledons: An introduction science-and-technology-89351 with special reference to the anatomy of 17. Obembe OA. Stomata complex in some the leaf and stem. Proceedings of the shrubs and trees. Global Journal of Linnean Society of London. 1942;155(3): Biology, Agriculture and Health Science. 211-223. 2015;4(2):164-172 27. Mbagwu FN, Inyama CN. Stem anatomy of 18. Metcalfe CR, Chalk L. Anatomy of the three Chrysophyllum Species Dicotyledons. Volume 1. Oxford University (Sapotaceae) and their relevance for Press, London; 1950. taxonomy (Systematic Botany). 19. Pant DD, Verma BK. Taxonomy of the International Conference on Plant genus Ephedra: Significance of stem and Physiology and Pathology. June 09-10, leaf epidermis and cuticle. Botanical Dallas, USA; 2016. Journal of the Linnean Society. 1974;69: 28. Aziagba BO, Okeke CU. Taxonomic 287-308. significance of stem and petiole anatomy 20. Wilkinson HP. The plant surface of three varieties of Vigna unguiculata. (mainly leaf). In Metcalfe CR, Chalk L. American Journal of Life Sciences (Eds.). Anatomy of the Dicotyledons Research. 2017;5(1):1-5. nd (2 ed.). Oxford, England: Oxford Press; 29. Goswami S. Anatomy in relation to plant 1979. Taxonomy; 2018. 21. Adegbite AE. Leaf epidermal studies in Available:https://www.biologydiscussion.co three Nigerian species of Aspilia m/plant-taxonomy/30463. (Heliantheae-Asteraceae) and two hybrids. 30. Cavente AM, Andreata RHP, Vieira RC. Nigerian Journal of Botany. 1995;8:25-33. Stem anatomy of Rhipsalis (Cactaceae) 22. Pandey BP. Plant Anatomy: Including and its relevance for taxonomy. Plant Embryology and Morphogenesis of Systematics and Evolution. 2008;276 Angiosperms (6th ed.). New Delhi: S. (1):1-7. Chand; 2004. 31. Kaplan Z, Symoens J. Taxonomy, 23. Nurul-Aini CAC, Noraini T, Latiff A, Amiruldistribution and nomenclature of three Aiman AJ, Ruzi AR, Idris S. Taxonomic confused broad-leaved Potamogeton Significance of Leaf Micromorphology in species in Africa and surrounding islands. Some Selected Taxa of Acanthaceae Botanical Journal of the Linnean Society. (Peninsular Malaysia). AIP Conference 2005;148(3):329-357. Proceedings. 2014;727-733 _________________________________________________________________________________ © 2022 Youkparigha et al.; This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Peer-review history: The peer review history for this paper can be accessed here: https://www.sdiarticle5.com/review-history/96922 54