Dioscorea bulbifera – plant in flowering. They were washed in cacodylate buffer, post-fixed in 1% buffered osmium tetroxide for 3 h at room temperature and washed again. Scale bars = 1 µm. The effects of Yam (Dioscorea bulbifera) intake on small intestine morphology in streptozotocin‐induced diabetic rats Louise da S. Asht. Borderea), gemmate sexine. 39. Pollen size, however, is very different in both species (Table 1). 18). D. nipponica (sect. 10. Enantiophyllum) distal polar view, disulculate, perforate. Measurements of the shortest equatorial axis (SEA) range from 13 µm (D. nako, D. ovinala, D. sinuata) to 45 µm (D. rupicola), compared with values of between 10 and 34 µm found by Schols et al. Whether Dioscorea has an endexine remains unclear. Pl. Fig. and D. smilacifolia DE WILD. Therefore, aperture number was established from LM observations (Figs 6–14). (2001) were the first to focus on the relevance of pollen morphology in the infrageneric systematics of Dioscorea. The four Enantiophyllum species we have examined for this paper are all disulculate and have a high perforation density, ranging from 10 to 14 µm−2. The only difference is that D. galeottiana is perforate whereas D. glandulosa and D. piperifolia are cerebroid perforate. Enter the email address you signed up with and we'll email you a reset link. She also looked at six species of section Cycladenium which were all perforate and six species of section Monadelpha, in which both ornamentation types occur. To distinguish between the clearly distinct rugulate and cerebroid perforate ornamentation, we adopt Su's terminology. The remaining 15% of the species examined have both disulculate and monosulcate pollen, even within one anther (Table 1). This is supported by our pollen data because they are the only perforate Malagasy species. Moreover, the striate sexine of section Stenophora seems to have arisen independently, given the isolated position of the section in recent molecular and micromorphological analyses (Caddick et al., 2002a). data), a close relative of Dioscorea (Caddick et al., 2002a). This paper adds new data on the pollen and orbicule morphology of 61 Dioscorea L. (Dioscoreaceae) species to the survey of Schols et al. Leaves are alter-nate, simple, three to five veined from base, glabrous, ovate … D. ovinala (sect. This section is remarkably diverse in its pollen morphology. The correlation between pollen size and tuber type, as suggested previously by P. Su (1987), is confirmed by our data. Fig. Invasive Plant Science and Management 9(3): 195-204. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. rotundata Poir. All other data are given for the 61 species observed in this paper. This species appears to show a stronger affinity with D. esculenta (sect. D. antaly (sect. Dioscorea bulbifera Linn. Fig. D. nummularia (sect. Fig. About 54% of the total number of species examined are perforate, 28% are striate, 6% are perforate to microreticulate (features of both ornamentation types are observed in the same grain), and 6% are cerebroid perforate. D. orientalis, perforate to microreticulate sexine. Gemmate or-namentation was not found in the species examined by Schols et al. The results also supported the hypothesis of Su (1987) that pollen of taxa with annual tubers is smaller than that of sections with persistent tubers. Cotinifoliae), in some species of section Stenophora, and in a few New World sections (e.g. All cerebroid perforate species from the New World lack this perforation dimorphism (Figs 23, 24). Embryogenesis was induced by culturing in vitro grown axillary bud meristems on MS medium supplemented with 2.0 mg per liter 2,4-D. After cryopreservation, recovery growth of embryogenic culture up to 53.3 percent was … These species have an average LA of 20 µm and 22.5 µm, respectively. hirtiflora Benth.,D. Cerebroid perforate ornamentation (Figs 23, 24, 26). Fig. The occurrence of yet another ornamentation type in section Stenophora underscores the eurypalynous character of this section. D. anomala (sect. Academia.edu no longer supports Internet Explorer. Seasonal growth, biomass allocation, and invasive attributes manifested by Dioscorea bulbifera L. (air-potato) plants generated from bulbils in Florida. A gemmate sexine is also found in the ant-pollinated D. pyrenaica from southern Europe (Garcia et al., 1995). The plants sometimes also have small underground tubers. 29. A combined molecular–morphological analysis is needed to investigate this hypothesis. José Luis Ramírez Ascheri. The wall structure of Dioscorea pollen is always tectate–columellate and there is little variation in exine thickness (0.6–1.5 µm) for the species examined in this survey, which agrees with that found by Schols et al. Borderea), striate sexine, striations are arranged in concentric polygons. andD. Fig. The evolution of a striate sexine in Madagascar could be linked to a specific Malagasy pollinator but little pollination data exist for Dioscorea. are presented. Fig. Cladistic analyses based on morphological and molecular data suggest that Tamus is nested within Dioscorea (Caddick et al., 2000) and recently Tamus was included in Dioscorea (Caddick et al., 2002b). Fig. 17. Varied morphology of the bioreduced silver nanoparticles included spheres, triangles, and hexagons. Sect. Fig. The former genus Tamus L. Tamus was recognized as a separate genus within Dioscoreaceae, placed close to Dioscorea and Rajania (Dahlgren, Clifford & Yeo, 1985), mainly based on its fruit type (a berry) that differs from that of Dioscorea (a capsule). This is different to Dioscorea, where the thick, channelled intine is concentrated at the apertures (Schols et al., 2001). The mean LA varies from 23 to 27 µm and the perforation size from 0.09 to 0.11 µm. ex Griseb., as the main source of … Vines with tuberous root stocks; Stem terete, twining to left. D. nummularia) (Fig. (2001) that monosulcate pollen is plesiomorphic in Diosocorea, as in monocots in general, because it is mainly confined to the basal section Stenophora, which could be sister to the rest of the genus, although it also occurs in section Borderea and (possibly) section Paramecocarpa (Table 1), which are embedded well within Dioscorea. Dioscorea belongs to the monocotyledons, family Dioscoreaceae, subfamily Dioscoreoideae. (2001) reported perforate (Figs 15–19), striate (Figs 20–22), and microreticulate sexine patterns. We are grateful to Dr Eric Schoeters, Marcel Verhaeghen and Anja Vandeperre for technical assistance and Dr Raymond van der Ham for a detailed review. They occur in Amaryllidaceae (Snijman & Linder, 1996), some Arecaceae (Harley, 1998), and Pontederiaceae (Simpson, 1987; Ressayre, 2001) in monocots, and in Trimeniaceae, some Annonaceae, Eupomatiaceae, Calycanthaceae, and Hydnoraceae (usually placed among magnoliids) in basal angiosperms (Furness, Rudall & Sampson, 2002; Watson & Dallwitz, 2002). Macrogynodium) show a somewhat rugulate sexine pattern. Perforation density (number of perforations per µm2) seems to characterize some sections, especially when combined with perforation size.