Webbia Journal of Plant Taxonomy and Geography ISSN: 0083-7792 (Print) 2169-4060 (Online) Journal homepage: http://www.tandfonline.com/loi/tweb20 Systematic significance of foliar epidermis and tendril morphology in three West African genera of Cucurbitaceae: Momordica L., Luffa Mill. and Trichosanthes L Akeem Babalola Kadiri & James Dele Olowokudejo To cite this article: Akeem Babalola Kadiri & James Dele Olowokudejo (2016): Systematic significance of foliar epidermis and tendril morphology in three West African genera of Cucurbitaceae: Momordica L., Luffa Mill. and Trichosanthes L, Webbia, DOI: 10.1080/00837792.2015.1108683 To link to this article: http://dx.doi.org/10.1080/00837792.2015.1108683 Published online: 06 Jan 2016. Submit your article to this journal View related articles View Crossmark data Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tweb20 Download by: [Akeem Kadiri] Date: 06 January 2016, At: 13:55 Webbia: Journal of Plant Taxonomy and Geography, 2016 http://dx.doi.org/10.1080/00837792.2015.1108683 Systematic significance of foliar epidermis and tendril morphology in three West African genera of Cucurbitaceae: Momordica L., Luffa Mill. and Trichosanthes L Akeem Babalola Kadiri* and James Dele Olowokudejo Department of Botany, University of Lagos, Lagos, Nigeria (Received 26 June 2015; accepted 13 October 2015) Momordica, Luffa and Trichosanthes are important cucurbitaceous plants whose foliar epidermal characters are sparsely documented. A combined investigation of leaf epidermis and tendrils of the species was carried out with the aid of light and scanning electron microscopy, and visual assessment. All Momordica species have hypostomatic leaves except M. balsamina whose leaves are amphistomatic. This adds to our knowledge of range of stomatal distribution in Momordica which hitherto, is reported hypostomatic. It also raises doubt about the naturalness of Sect. Momordica. Only M. multiflora is glabrous and M. angustisepala alone is pubescent on the epidermal surfaces. Epidermis of Luffa is amphistomatic and non-cystolithic whereas, it is hypostomatic and cystolithic in Trichosanthes. Tendrils branches arise from the base in Luffa (3–4 in number) and Trichosanthes (2–3 in number) whereas in Momordica they may not branch or are bifurcated, with one being vestigial. These comparative data support classifying the three genera in sepa- rate tribes. In particular, characters of the leaf epidermis will assist in identifying the species even when the leaf sam- ples are fragmentary, or when there is a mix-up, the usual state of herbal materials in the African markets. Keywords: Cucurbitaceae; cuticle; leaf epidermis; microscopy; taxonomy; tendrils Introduction et al. (2006), Kocyan et al. (2007), Ali et al. (2010), The infra-familiar and generic composition in Cucur- Schaefer and Renner (2011), Bharathi, Parida, et al., bitaceae has been reviewed at different times and signifi- (2012a) and Guo et al. (2012). fi cant amendments were made (Hutchinson and Dalziel The latest classi cation by Schaefer and Renner 1958; Jeffrey 1962, 1980, 1990, 2005; Ali et al. 2011; (2011) recognized 15 tribes in the family following the Schaefer and Renner 2011). However, inadequate infor- work of Cogniaux (1881) and Jeffrey (2005). Momor- mation on distribution pattern, insufficiency of materials dica, the primary focus of this work, was formerly in the fi for study and variable morphology of some taxa have tribe Jolif eae (Jeffrey 2005) but is now placed in the been reported as responsible for the limited understand- new tribe Momordiceae and recognized as a mono- ing of certain taxa in this family (Hutchinson and Dalziel phyletic genus (Schaefer and Renner 2011) despite the 1958; Schaefer and Renner 2010, 2011). In addition, inclusion of some poorly known species. Luffa and some species from domesticated and wild populations Trichosanthes L., the secondary concern of the study, are Downloaded by [Akeem Kadiri] at 13:55 06 January 2016 are known to hybridize freely (Schaefer and Renner exo-morphologically distinct; but their tribal position is 2010; Bharathi, Munshi et al. 2012; Guo et al. 2012), not yet clear. Tribal placement of Luffa has been contro- leading to polymorphism and increased confusion in versial. taxon identification. Reversal from dioecy to monoecy Jeffrey (1962, 1980, 1990, 2005) placed Luffa in dif- – and vice versa in genera such as Momordica L., c. 24 ferent tribes Cucurbiteae and Benincaseae at different dioecious and 23 monoecious species in Africa (Schaefer times but Trichosanthes has been consistently placed in and Renner 2010) and genera such as Luffa Mill. (Schae- Trichosantheae. These genera are now placed in an old – – fer and Renner 2011) and Bryonia L. (Volz and Renner tribe Sicyoeae based on molecular data (Schaefer and 2008) is another important reason for misidentification in Renner 2011). In view of these changes, we considered this family. leaf epidermis and tendril morphology for possible useful Many studies focused on the problems above, have taxonomic data that will enhance sharp discrimination of improved our knowledge of taxon relationships in Cucur- the taxa. fi bitaceae, e.g. morphology by Hutchinson and Dalziel The genera cannot be identi ed using fragmented (1958), Jeffrey (1962, 1980, 1990, 2005), Schaefer and leaf samples because of limited information on the sub- fi Renner (2010) and Omar (2009); anatomy by Sawhney ject and lack of materials to be used as an identi cation (1920), Metcalfe and Chalk (1950, 1979), Ali et al. guide. In West Africa, there is an old account on mor- (2011) and, Aguoru and Okoli (2012); cytology by phology (Hutchinson and Dalziel 1958), limited anatomi- Bharathi et al. (2011) and molecular studies by Zhang cal information (Metcalfe and Chalk 1950, 1979; Aguoru *Corresponding author. Email: [email protected] © 2016 Dipartimento di Biologia, Università di Firenze 2 A.B. Kadiri and J.D. Olowokudejo and Okoli 2012) and minimal data on leaf epidermal Line drawings of the epidermis were obtained using a morphology (Kadiri 2003). This situation has hampered camera lucida drawing apparatus. Photomicrographs were the optimal use of the species in crude drug discovery in obtained with a digital camera attached to a CE Olympus spite of the high medicinal potency reported in certain compound microscope. Images were produced and edited folkloric accounts (Oliver 1960; Agoha 1963; Burkhill on the computer. The formula for stomatal index of Cutter 1985). Furthermore, when there is mix-up of leaves due (1978) was adopted,namely: Stomatal Index (%) = (NS × to fragmentation (the condition in which medicinal plants 100/(ES + NS), where NS is the number of stomata and are available in African markets), misidentification of ES is the number of epidermal cells. Tendrils of all the taxa persists. This study therefore, reflects the pattern of herbarium specimens were examined while those of other inter- and intra-generic relationships in the three genera, samples were assessed in situ in their natural populations. so as to contribute useful data that can be combined with Three morphological characters such as number of other data for a meaningful phylogenetic interpretation. branches, point of branching and twisting pattern, whether The work also attempts to validate the existing infra- lax or deep, were studied. generic classification of Momordica by Schaefer and For electron microscopy, small pieces (c. 7 mm2)of Renner (2011). We addressed these concerns using com- the leaf were fixed on scanning electron microscope bined data from tendrils and leaf epidermis correlated on stubs with double-sided tape and sputter coated with the maximum likelihood phylogenetic tree branches of gold. Specimens were examined and photographed in a Schaefer and Renner (2011). Jeol JSM 35 scanning electron microscope. The three genera (Momordica, Luffa and Trichosan- thes) are either cultivated or grow in the wild. They have pantropical distribution worldwide (Willis 1966; Schaefer Results and Renner 2010, 2011) and the species have culinary, The seven West African species of Momordica in the medicinal and many other commercial values (Oliver tribe Momordiceae, were investigated. In the genus, the 1960; Agoha 1963; Welihinda et al. 1982; Burkhill leaves are hypostomatic in all species except Momordica 1985; Jiratchariyakul et al. 2001; Grover and Yadav balsamina L. which is amphistomatic (Figure 1C, D; 2004). Table 1). The leaves of Momordica multiflora Hook.f. are glabrous whereas in other species, they are pubescent (Table 1). The anticlinal walls are undulate on the abaxial Materials and methods surface of all species; although a slightly curved pattern Both herbarium and field specimens were used for the may be found in Momordica charantia L. (Figure 1G, H; study. Provenances of the herbarium samples are shown Table 1) and Momordica cissoides Planch. ex Benth. in Appendix I. Herbarium abbreviations follow Holm- (Figures 2A, B, 3G, H; Table 1). Curved, undulate and gren et al. (1990). For light microscopy, the approach straight anticlinal walls were found on the adaxial surface adopted followed Kadiri (2003), Kadiri and Ayodele of all species (Table 1). The cell shape is irregular on (2003), Kadiri et al. (2009) with some modifications. A both surfaces of the epidermis in all species except whole leaf or 1- to 5-cm² portions sectioned from the Momordica cabraei (Cogn.) C. Jeffrey, which has polyg- standard median portion of the lamina (i.e. near the mid- onal cell shape on the adaxial surface (Figure 1E; rib) were examined in three to five specimens. Dried Table 1). Stomatal type is generally anomocytic in the Downloaded by [Akeem Kadiri] at 13:55 06 January 2016 leaves were swollen by boiling in water for 30 minutes, genus. The trichome types recorded were long or short and then soaked in concentrated trioxonitrate (v) acid conical in Momordica angustisepala Harms (Figure 5B; (HNO3) in capped specimen bottles for about 2–5 hours Table 1) and Momordica foetida Schumach. (Figure 5H; to macerate the mesophyll. Tissue disintegration was Table 1) on the adaxial suface, and also in M.