Pollen variability in species of Dioscorea L. (Dioscoreaceae)

Abstract

Dioscoreaceae is characterised by wide morphological variability, including hermaphrodite genera such as Tacca J.R.Forst. et G.Forst, Trichopus Gaertn., and Stenomeris Planch. and some dioecious species in the genus Dioscorea L. This study aimed to describe the pollen characters of 81 species of Dioscorea occurring in Brazil, contributing to a broader knowledge of Dioscoreaceae by investigating the possibility of using pollen attributes in taxonomic classification. Pollen grains were treated by lactic acetolysis, measured, described, and photomicrographed. The results were subjected to statistical analysis. Unacetolysed pollen grains were mounted on stubs with carbon tape for scanning electron microscopy. Our results showed that the studied species have heteropolar pollen grains, ranging from small to medium, with mainly elliptical, circular, and triangular ambs. Pollen grains with 1, 2, or 1‒2 apertures were recorded in most species, as well as nine types of sexine ornamentation (perforate in 23 species, striate in 23 species, microreticulate in 15 species, reticulate in eight species, rugulate in seven species, bireticulate in two species, rugulate-verrucate in one species, cristate in one species, and gemmate in one species). The sexine had striae in different shapes and directions. Micromorphological results of pollen characters were of great importance for species delimitation. The findings reported herein demonstrate that palynological analysis can provide valuable information to improve taxonomic classification and contribute to a more robust phylogenetic representation of the genus.

Keywords:

• Brazil
• Dioscoreales
• morphology
• ornamentation
• palynology

Acknowledgements

V. Esteves and C. B. F. Mendonça are grateful to the Brazilian National Council for Scientific and Technological Development (CNPq) for the research grant (304910/2019-8, 31618/2021-9). All authors extend their thanks to the Rio de Janeiro State Research Foundation (FAPERJ) (grant nos 26.200.345/2023 and 26.0003/015254/2021). The authors are grateful to the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) and the Post-Graduate Support Programme (PROAP) for awarding scholarships. The authors also thank the herbarium curators for providing access to their collections and the Scanning Microscopy Laboratory, National Museum, Federal University of Rio de Janeiro, Brazil, for their support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Specimens investigated

Dioscorea alata L. – West Indies, Tobago, Botanic Station, WE Broadway 3149 03/XI/1909 (S).

Dioscorea amaranthoides C. Presl – Brazil, Mato Grosso, Juruena, FC Hoehne s/n°, VI/1909 (R53041).

Dioscorea amazonum Griseb. – Brasil, Pará, Oriximiná, Igarapé próximo a cachoeira do ‘Benjamim’, Couto RS 63, 27/X/2007 (RB).

Dioscorea asperula Pedralli – Brasil. Minas Gerais: Nova Ponte, Pedralli G 1436 03/V/1988 (ICN).

Dioscorea baracoensis (R. Knuth) Raz – Cuba, Guantánamo, Oriente, Bayate in Monte Oscuro, EL Ekman 6707, 01/X/1916 (S).

Dioscorea bartlettii C.V. Morton – México, Chiapas, D Álvarez 959, s/n°, V/2002 (MBM).

Dioscorea basiclavicaulis Rizzini et A. Mattos – Brasil, Espírito Santo, Água Doce do Norte, Propriedade Laura Bernardino, FRM Fraga 231, 17/XI/2018 (RB).

Dioscorea bemarivensis Jum. et H. Perrier – Madagascar, Toliara, Manasoa, Mahafaly. Karl Afzelius s/n, 29/I/1913 (S17-42247).

Dioscorea besseriana Kunth – Chile, Santiago, Cerro San Cristóbal in Santiago (excl. Juan Fernandez Islands), M Gusinde 706, X/1920 (S).

Dioscorea birmanica Prain et Burkill – Myanmar, Birma, Rangum, A Meebold 15630, V/1911 (S).

Dioscorea brachybotrya Poepp. – Chile, Juan Fernandez Islands, Valdivia, Payahuinte, Los Lagos, 160 m, P Ath 356, XII/1924 (S).

Dioscorea bradei R. Knuth. – Brasil, Rio de Janeiro, Serra do Itatiaia, AJ Sampaio s/n°, V/1926 (R50932).

Dioscorea buchananii Benth. – Mozambique, Zambézia, Quelimane, District, Namagoa, HK Faulkner 295, 22/IV/1949 (S).

Dioscorea campanulata Uline ex R. Knuth – Brasil, Rio de Janeiro, São Fidélis, Serra Pedra do Marial, Parque Estadual do Desengano, C Baez 447b, 27/I/2016 (RB).

Dioscorea carionis Prain et Burkill – México, S. Martin, Zaratepequez, Bernoulli 848, II/1878 (K).

Dioscorea carpomaculata Téllez et Schubert – México, ES Martínez 14335, 25/X/1985 (MBM).

Dioscorea cienegensis R. Knuth – Brasil, Paraná, Foz do Iguaçu, Parque Nacional do Iguaçu, Trilha das Cataratas, PLR de Moraes 8750, 13/X/2011 (MBM).

Dioscorea cinnamomifolia Hook. – Brasil, Espírito Santo, Castelo, Topo do Forninho, Inselbergues. Parque Estadual do Forno Grande, CN Fraga 2378, 21/I/2009 (RB).

Dioscorea cochleari-apiculata De Wild. – Zambia, Tanganyika, Msipa, Dist. 15 miles from north Rhodesian border. 1050 m, HM Richards 16840, 15/X/1962 (S).

Dioscorea collettii Hook. f. – Taiwan, Haulien Hsien, Hsiulin Hsiang, Taroko National Park, at road mileage sign 151 km along Provincial Highway 24° 12′ 44″ N/121° 25′ 25″ E 1200 m. Ching-I Peng and A Anderberg 17291, 15/VI/1999 (S).

Dioscorea communis (L.) Caddick et Wilkin – Switzerland, Bern, Schweiz, Spiez, Hj. and A. Hafström s/n°, 20/VI/1894 (S15-2072).

Dioscorea composita Hemsl. – Honduras, Departament Choluteca, Thickets of Cedeños beach, Fonseca gulf. Vine on Jatropha curcas. AR Molina and AR Molina 25874, 11/X/1970 (S).

Dioscorea cordata (L.) Raz – Haiti, Hispaniola, Civ, Haiti, Massif de la Hotte, group. Morne Rochelois, Miragoane, Limestone crag at Quate. 1000 m. EL Ekman 8600, 17/VII/1927 (S).

Dioscorea coriacea Humb. et Bonpl. ex Willd. – Columbia, Huila, La Plata, In silva primaeva 2600 m, Kjell von Sneidern, 2050, 21/III/1939 (S).

Dioscorea cotinifolia Kunth – South Africa, Mpumalanga, Komatie Poort, Barberton, Transvaal. 3100 m. FA Rogers 543, s/data (S).

Dioscorea cyanisticta Donh. Sm. – México, Chiapas, Mpio, Unión Juárez, En Chiquihuite, ES Martínez 20534, 29/IV/1987 (RB).

Dioscorea cynanchifolia Griseb. – Brasil, Rio de Janeiro, Rio de Janeiro, Trilha Paineiras, Mirante da Freira, Parque Nacional da Tijuca, RG Barbosa-Silva 750, 17/IV/2017 (RB).

Dioscorea debilis Uline ex. R. Knuth – Brazil, Minas Gerais, Santana do Riacho, Serra do Cipó, Rodovia Belo Horizonte, Conceição do Mato Dentro, ca. 18 km após Chapéu de Sol, Fazenda Cachoeira da Capivara, VC Souza et. al. 8218, 10/III/1995 (MBM).

Dioscorea delicata R. Knuth – Brasil, Santa Catarina, Joinville, Serra Dona Francisca, Trilha do Castelo dos Bugres, P Schwirkowski 2531, 30/X/2017 (MBM).

Dioscorea deltoidea Wall. ex Griseb. – Pakistan, Kashmir, Hazara, Kaghan, Naran 2500 m, E Emanuelsson 2702, 27/VI/1999 (S).

Dioscorea densiflora Hemsl. – Guatemala, Department of Peten, on old Santa Ana Trail, about 6.5 km S.E.E. of Santa Elena, Elias Contreras 2023, 23/III/1961 (S).

Dioscorea dodecaneura Vell. – Brasil, São Paulo, Pindorama, VC Souza et al. 5721, 15/IV/1994 (ESA).

Dioscorea dregeana (Kunth) T. Durand et Schinz – South Africa, Eastern Cape, south side of Umtamvuma forest, 2 km upstream from Alp Pont Holiday resort, opposite Leopard Beach. R Brand and T Abbatt 621, 19/VIII/2003 (S).

Dioscorea dumetorum (Kunth) Pax – Congo Belge, Brazzaville, Matadi, Dacremont 417,?/?/1933 (S).

Dioscorea elephantipes (L’ Hér.) Engl. – South Africa. Eastern Cape. Uitenhaag: Zwischen Karrogebüsch am Zondagrivier, unter 1000, Ecklon & Zeyher s/n°, s/data (S17-42601).

Dioscorea fandra H. Perrier – Madagascar, Toliara, Manasoa Tanosy. Karl Afzelius s/n°, 11/I/1913 (S17-42616).

Dioscorea flabellispina Couto et al. – Brasil. Serra Pedra do Marial. Área de afloramentos rochosos ao chegar na parte alta da montanha. Parque Estadual do Desengano, RS Couto 235, 28/VIII/2009 (R).

Dioscorea floribunda M. Martens et Galeotti – México, ES Martínes 8595B, 22/X/1984 (MBM).

Dioscorea fordii Prain et Burkill – China, Hainan, Chim Fung Ling near Sam Mo Watt village (Kan-en District), SK Lau 3768, 14/IV/1934 (S).

Dioscorea glabra Roxb. – Vietnam, Ho Chi Minh, Hab. Cochinchina, L. Pierre s/data (S17-42647).

Dioscorea gracillima Miq. – Japan, Yamanashi, Honshu, Yamanaka Lake in Kai, M. Togasi 1060, 05/VII/1954 (S).

Dioscorea hamiltonii Hook. f. – Myanmar, Tenasserim and Andamans, Helfer 5553 1862-1863 (S).

Dioscorea hassleriana Chodat – Brasil, Mato Grosso, Corumbá, FC Hoehne 3775 II/1911 (R).

Dioscorea hastifolia Nees – Australia, Western Australia, Australiae occidentalis. District Swan, Darling Range, E. Pritzel 303, 05/1901 (S).

Dioscorea hispida Dennst. – India, Jammu and Kashmir, West Bengal, Nymensingh-Kangsa, SK Mukerjee 1608, 23/IV/1946 (S).

Dioscorea humifusa Poepp. – Chile, Coquimbo, Coquimbo, Las Cardas, (excl. Juan Fernandez Islands), 400 m, B Sparre 2675, 23/IX/1947 (S).

Dioscorea hyalinomarginata Raz – Haiti, Hispaniola, Montagnes du From d'Eau, edge of Riviere Grande Aochue, EL Ekman 2287, 27/X/1924 (S).

Dioscorea japonica Thunb. – Japan, Honshu, Yamamoto in Settsu, M Togasi 1098, 06/VII/1954 (S).

Dioscorea kamoonensis Kunth – East Tibet and southwest China, south end of the Sengyneh valley, 6000 m, G. Forest 8865 VIII/1912 (S).

Dioscorea laxiflora Mart. ex Griseb. – Brasil, Rio Grande do Sul, Osório, Morro Alto, JL Waechter 2124, 07/VI/1985 (ICN).

Dioscorea leptostachya Gardner – Brasil, Rio de Janeiro, Lagoa Rodrigues de Freitas, CAW Schwacke 1887 s/data (R).

Dioscorea macrostachya Benth. – Brasil, Amazonas, Rio Negro, próximo ao aeroporto de S. Gabriel, JM Pires 146799, 17/III/1975 (IAN).

Dioscorea maianthemoides Uline ex R. Knuth – Brasil, Goiás, Alto Paraíso de Goiás, Chapada dos Veadeiros, A Fonseca Vaz, 870, 28/I/1991 (RB).

Dioscorea medusae F Fraga, R Couto et JMA Braga – Brasil, Espírito Santo, Município de Águia Branca, Comunidade São Pedro, Pedra da Bandeira. Propriedade do Sr. João Ferreira, 800 m. 18.9846114°S, 40.659528°W, FRM Fraga and RS Couto 163, 4/XII/2017 (RB).

Dioscorea minima C.B. Rob. et Seaton – Mexico, Vicinity of Morelia, State of Michoacán, Punguato, 200 m. BroG Arsène 2738, 26/VI/1909 (S).

Dioscorea multinervis Benth. – México, Satet of Michoacan, Damp glades near Patzcuaro, C. G. Pringle 4158, 23/ VII/1892 (S).

Dioscorea nipponica Makino – Japan, Nagano, Honshu, Nobeyama in Shinano, M. Togasi 1214, 13/ VIII/1955 (S).

Dioscorea nummularia Lam. – Pacific Islands, Fiji, Viti Levu, Tailevu, Hills east of Wainimbuka River, in vicinity of Nadkuivuna, along road. 100-200 m, AC Smith 7001, 14-26/IV/1953 (S).

Dioscorea orientalis (J. Thiébaut) Caddick et Wilkin – Lebanon, Liban Littoral, raus mue gorge, prés de Djebail. J. Thiébaut s/n°, I/1934 (S17-42852).

Dioscorea obtusifolia Hook. et Arn. – Chile, Provincia, Coquimbo, Depto, La Serena, Punta de Teatinos a 16 km norte de La Serena cerca del Portezuelo, RH Wagenknecht 417, 20/ VII/1952 (S).

Dioscorea pallens Schlecht – México, GC Villalobos 228, 21/XI/1987 (MBM).

Dioscorea pedalis (R. Knuth) R. S. Couto et J. M. A. Braga – Brasil, Rio de Janeiro, Itatiaia, Parque Nacional de Itatiaia, Encosta rochosa, úmida na estrada cerca de 50 m antes do abrigo Rebouças. RS Couto et al. 587, 7/XI/2011 (R).

Dioscorea pedicellata Phil. – Chile, Juan Fernandez Islands, Bío-Bío, Talcuhano, WH Harvey s/n°, VI/1856 (S17-42864).

Dioscorea pentaphylla L. – Sri Lanka, Kandy, Flora of Ceylon, District Kadugannawa, 7° 15′ N / 80° 31’ E, Fagerlind and Klackenberg 294, 11/XI/1979 (S).

Dioscorea polygonoides Humb. et Bonpl. ex Willd. – Ecuador, Esmeraldas 15’ al sur Bosque transicional seco-húmedo tropical 0° 53′ N/79° 40′ W. 80 m. X Cornejo and C. Bonifaz 2660, 23/V/1994 (S).

Dioscorea polystachya Turcz. – Japan, Gifu, Foot of Kiso-ontake, Masuda-dun, Hida, Hondo, M Mizushima 13408, 18/VII/1954 (S).

Dioscorea preussii Pax – Tanzania, Ostafrika (Tanganjika Terr.) Bezirk Lindi, 100 km. NW Lindi, 200 m. HJ Schlieben 6044, 21/II/1935 (S).

Dioscorea pyrenaica Bubani et Bordère ex Gren. – França, Midi-Pyrénées, 1500 m, E Wall 39, 28/ VII/1924 (S).

Dioscorea pseudomacrocapsa G.M. Barroso et al. – Brasil, Rio de Janeiro, Maricá, Itaipuaçu, acesso pela Estrada de Itaipuaçu e pela Rua Cinco Monumento Natural Municipal da Pedra de Itaocaia, DNS Machado 753, 17/IV/2014 (RB).

Dioscorea quinquelobata Thunb. – Japan, Kagoshima, Loc. Kyushu, Kagoshima Pref., Tarumizu-shi, Takakuma, the Experimental Forest of Kagoshima University, in the east of Sakurajima Volcano, F Konta and H Noguchi 35754, 24/II/2010, (S).

Dioscorea remotiflora Kunth – México, AV Campos 2570, 05/X/1988 (MBM).

Dioscorea sansibarensis Pax – Tanzania, Tanganyika, Pangani Distr. Bushivi Estate HGK Faulkner 580, 24/V/1950 (S).

Dioscorea saxatilis Poepp. – Chile, Orientalis, El Salto prope Valparaiso (excl. Juan Fernandez Islands), P Dusén 29, 28/ VI/1896 (S).

Dioscorea schimperiana Hochst. ex Kunth – Tanzania, Africa Oriental, Nyassa Hochland, Station Kyimbila, 1300 m, A Stolz 1961,?/1913 (S17-42960).

Dioscorea spiculiflora Hemsl. – México, Carretera Xalapa, Veracruz desviacion para los Banos de Carrizal, Mun. de Emiliano Zapata, JI Calzada 2046 08/X/1975 (RB).

Dioscorea sphaeroidea R Couto et JMA Braga – Brasil. Rio de Janeiro: Teresópolis. Parque Nacional da Serra dos Órgãos. Pedra do sino, próximo ao marco no cume, RS Couto 316, 31/III/2010 (RB).

Dioscorea sylvatica Eckl. – South Africa, Orange Free State, Dist. Harrismith Besters ulei, HG Flanagan 2001, XII/1893 (S).

Dioscorea tokoro Makino ex Miyabe – Japan, Nippon, prov. Schimotsuk in radicibus montis Nahtai-San, in ripa lacus Chutzenji 14 km procula Nikko, SJ Enander s/n°, 14/VII/1913 (S17-42969).

Dioscorea tomentosa J. König ex Spreng. – Sri Lanka, Matale, Flora of Ceylon, District Dambulla, F Fagerlind 1169, 27/XI/1973 (S).

Dioscorea trisecta Griseb. – Brazil, Minas Gerais, JF Widgren s/n°,?/1845 (R 50876).

Dioscorea villosa L. – United States, Hawaii, Illinois, Peoria County, Peoria Heights, Open woods, VH Chase 15310, 30/VI/1958 (S).

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [Proc. 304910/2019-8]; Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro [26.200.345/2023 and 26.0003/015254/2021].