Abstract
Pleurothallidinae orchids have been the focus of many multidisciplinary studies due to their challenging systematics and taxonomy. The synapomorphies already recognized in the group are mostly related to floral characters, the last proposed being the occurrence of alkanes in the floral fragrance. The composition of the floral bouquet varied significantly among the studied species, leading us to hypothesize that the variations in volatiles emitted could be linked to the structure of osmophores, especially when comparing the myophilous and sapromyophilous pollination syndromes. Sepals and labellum at different developmental stages of seven Brazilian Pleurothallidinae species were examined using light, scanning, and transmission electron microscopy. Nectar reabsorption was assessed by Lucifer Yellow CH tracer and imaged under confocal microscopy. Nectaries were restricted to the labellum of the myophilous species, whereas osmophores occurred in the dorsal and/or lateral sepals, varying according to species. In the sapromyophilous species, floral nectaries were not detected and osmophores were restricted to the labellum. Osmophore structure was correlated with the volatiles emitted, being the trichome osmophores notably present on the sepals of both myophilous species that possess nectaries. For the first time, we demonstrated reabsorption of the released nectar in Pleurothallidinae and the occurrence of a unique gland named sticky-exudate glands, which occurred in the lateral sepals and labellum of Echinosepala aspasicensis, a sapromyophilous species, that released a heterogeneous exudate composed of polysaccharides and lipids. Similar glands have been reported in Bulbophyllum, highlighting the convergence between both groups.
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References
Aguiar-Dias ACA, Yamamoto K, Castro MM (2011) Stipular extranuptial nectaries new to Polygala: morphology and ontogeny. Bot J Linn Soc 166:40–50. https://doi.org/10.1111/j.1095-8339.2011.01123.x
Antoń S, Komoń-Janczara E, Denisow B (2017) Floral nectary, nectar production dynamics and chemical composition in five nocturnal Oenothera species (Onagraceae) in relation to floral visitors. Planta 246:1051–1067. https://doi.org/10.1007/s00425-017-2748-y
Bänziger H (1996) The mesmerizing wart: the pollination strategy of epiphytic lady-slipper orchid Paphiopedilum villosum (Lindl.) Stein (Orchidaceae). Bot J Linn Soc 121:59–90. https://doi.org/10.1111/j.1095-8339.1996.tb00745.x
Barbosa AR, Melo MC, Borba EL (2009) Self-incompatibility and myophily in Octomeria (Orchidaceae, Pleurothallidinae) species. Plant Syst Evol 283:1–8. https://doi.org/10.1007/s00606-009-0212-6
Blanco MA, Barboza G (2005) Pseudocopulatory pollination in Lepanthes (Orchidaceae: Pleurothallidinae) by fungus gnats. Ann Bot 95:763–772. https://doi.org/10.1093/aob/mci090
Bogarín D, Fernández M, Borkent A, Heemskerk A, Pupulin F, Ramírez S, Smets E, Gravendeel B (2018) Pollination of Trichosalpinx (Orchidaceae: Pleurothallidinae) by biting midges (Diptera: Ceratopogonidae). Bot J Linn Soc 186:510–543. https://doi.org/10.1093/botlinnean/box087
Bohman B, Flematti GR, Barrow RA, Pichersky E, Peakall R (2016) Pollination by sexual deception—it takes chemistry to work. Curr Opin Plant Biol 32:37–46. https://doi.org/10.1016/j.pbi.2016.06.004
Borba EL, Semir J (1998) Wind-assisted fly pollination in three Bulbophyllum (Orchidaceae) species occurring in the Brazilian Campos Rupestres. Lindleyana 13:203–218
Borba EL, Semir J (2001) Pollinator specificity and convergence in fly-pollinated Pleurothallis (Orchidaceae) species: a multiple population approach. Ann Bot 88:75–88. https://doi.org/10.1006/anbo.2001.1434
Borba EL, Barbosa AR, Melo MC, Gontijo SL, Oliveira HO (2011) Mating systems in the Pleurothallidinae (Orchidaceae): evolutionary and systematic implications. Lankesteriana 11:207–221. https://doi.org/10.15517/lank.v11i3.18275
Bronner R (1975) Simultaneous demonstration of lipids and starch in plant tissues. Stain Technol 50:1–4. https://doi.org/10.3109/10520297509117023
Cardoso-Gustavson P, Davis AR (2015) Is nectar reabsorption restricted by the stalk cells of floral and extrafloral nectary trichomes? Plant Biol (Stuttgart) 17:134–146. https://doi.org/10.1111/plb.12208
Cardoso-Gustavson P, Aguiar JMRBV, Pansarin ER, Barros F (2013) A light in the shadow: the use of Lucifer Yellow technique to demonstrate nectar reabsorption. Plant Methods 9:20–26. https://doi.org/10.1186/1746-4811-9-20
Cardoso-Gustavson P, Campbell L, Mazzoni-Viveiros SC, Barros F (2014) Floral colleters in Pleurothallidinae (Epidendroideae: Orchidaceae). Am J Bot 101:587–597. https://doi.org/10.3732/ajb.1400012
Cardoso-Gustavson P, Sousa RS, Barros F (2017) Floral volatile profile in Pleurothallidinae, an orchid subtribe pollinated by flies: ecological and phylogenetic considerations. Phytochem Lett 22:49–55. https://doi.org/10.1016/j.phytol.2017.09.005
Chen F, Tholl D, Bohlmann J, Pichersky E (2011) The family of terpene synthases in plants: a midsize family of genes for specialized metabolism that is highly diversified throughout the kingdom. Plant J 66:212–229. https://doi.org/10.1111/j.1365-313X.2011.04520.x
Chiron GR, Guiard J, Van den Berg C (2012) Phylogenetic relationships in Brazilian Pleurothallis sensu lato (Pleurothallidinae, Orchidaceae): evidence from nuclear ITS rDNA sequences. Phytotaxa 46:34–58. https://doi.org/10.11646/phytotaxa.46.1.5
David R, Carde JP (1964) Coloration différentielle des inclusions lipidiques et terpéniques des pseudophylles du Pin maritime au moyen du réactif Nadi. Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences 258:1338–1340
Davies KL, Stpiczyńska M (2008) Labellar micromorphology of two euglossine-pollinated orchid genera; Scuticaria Lindl. and Dichaea Lindl. Ann Bot 102:805–824. https://doi.org/10.1093/aob/mcn155
Davies KL, Stpiczyńska M (2014) Labellar anatomy and secretion in Bulbophyllum Thouars (Orchidaceae: Bulbophyllinae) sect. Racemosae Benth. & Hook.f. Ann Bot 114:889–911. https://doi.org/10.1093/aob/mcu153
Davies KL, Turner MP, Gregg A (2003) A lipoidal labellar secretion in Maxillaria Ruiz & Pav. (Orchidaceae). Ann Bot 91:439–446. https://doi.org/10.1093/aob/mcg038
Davies KL, Stpiczyńska M, Rawski M (2014) Comparative anatomy of floral elaiophores in Vitekorchis Romowicz & Szlach., Cyrtochilum Kunth and a florally dimorphic species of Oncidium Sw. (Orchidaceae: Oncidiinae). Ann Bot 113:1155–1173. https://doi.org/10.1093/aob/mcu045
De DN (2000) Plant cell vacuoles: an introduction. CSIRO Publishing, Collingwood, Australia
Duque-Buitrago CA, Alzate-Quintero NF, Otero T (2014) Nocturnal pollination by fungus gnats of the Colombian endemic species, Pleurothallis marthae (Orchidaceae: Pleurothallidinae). Lankesteriana 13:407–417. 10.15517/lank.v13i3.14429
Evert RF (2006) Esau’s plant anatomy, meristems, cells, and tissues of the plant body: their structure, function, and development, 3rd ed. John Wiley & Sons, Hoboken, NJ
Frey-Wyssling A, Häusermann E (1960) Deutung der gestaltlosen Nektarien. Ber Schweiz Bot Gesell 70:151–162
Galetto L, Bernardello G, Rivera GL (1997) Nectar, nectaries, flower visitors, and breeding system in five terrestrial Orchidaceae from central Argentina. J Plant Res 110:393–403. https://doi.org/10.1007/BF02506798
Gontijo SL, Barbosa AR, Melo MC, Borba EL (2010) Occurrence of different sites of self-incompatibility reaction in four Anathallis (Orchidaceae, Pleurothallidinae) species. Plant Spec Biol 25:129–135. https://doi.org/10.1111/j.1442-1984.2010.00277.x
Heil M (2011) Nectar: generation, regulation and ecological functions. Trends Plant Sci 16:191–200. https://doi.org/10.1016/j.tplants.2011.01.003
Humeau L, Micheneau C, Jacquemyn H, Gauvin-Bialecki A, Fournel J, Pailler T (2011) Sapromyophily in the native orchid, Bulbophyllum variegatum, on Reunion (Mascarene Archipelago, Indian Ocean). J Trop Ecol 27:591–599. https://doi.org/10.1017/S0266467411000411
Jeger RN, Lichtenfeld Y, Peretz H, Shany B, Vago R, Baranes D (2009) Visualization of the ultrastructural interface of cells with the outer and inner surface of coral skeletons. J Electr Microscopy 58:47–53. https://doi.org/10.1093/jmicro/dfp005
Jersáková J, Johnson SD, Kindlmann P (2006) Mechanisms and evolution of deceptive pollination in orchids. Biol Rev Biol Proc Cambridge Philos Soc 81:219–235. https://doi.org/10.1017/S1464793105006986
Kaiser R (1993) The Scent of Orchids. Olfactory and chemical investigations. Editiones Roche, Amsterdam, The Netherlands
Karremans AP (2016) Genera Pleurothallidinarum: an updated phylogenetic overview of Pleurothallidinae. Lankesteriana 16:219–241. https://doi.org/10.15517/lank.v16i2.26008
Kivimäenpää M, Jonsson AM, Stjernquist I, Sellden G, Sutinen S (2004) The use of light and electron microscopy to assess the impact of ozone on Norway spruce needles. Environ Pollut 127:441–453. https://doi.org/10.1016/j.envpol.2003.08.014
Knust L, Samuels L (2009) Plant cuticles shine: advances in wax biosynthesis and export. Curr Opin 12:721–727. https://doi.org/10.1016/j.pbi.2009.09.009
Kowalkowska A, Kozieradzka-Kiszkurno M, Turzyński S (2015) Morphological, histological and ultrastructural features of osmophores and nectary of Bulbophyllum wendlandianum (Kraenzl.) Dammer (B. section Cirrhopetalum Lindl., Bulbophyllinae Schltr., Orchidaceae). Plant Syst Evol 301:609–622. https://doi.org/10.1007/s00606-014-1100-2
Kraus JE, Arduin M (1997) Manual básico de métodos em morfologia vegetal. Editora Universidade Rural, Rio de Janeiro, Brazil
Machado S, Paleari L, Paiva E, Rodrigues T (2015) Colleters on the inflorescence axis of Croton glandulosus (Euphorbiaceae): Structural and functional characterization. Int J Plant Sci 176:86–93. https://doi.org/10.1086/678469
Marques JPR, Amorim L, Spósito MB, Appezzato-da-Glória B (2013) Histopathology of postbloom fruit drop caused by Colletotrichum acutatum in citrus flowers. Eur J Plant Pathol 135:783–790. https://doi.org/10.1007/s10658-012-0120-4
McFarlane HE, Watanabe Y, Yang W, Huang Y, Ohlrogge J, Samuel AL (2014) Golgi and TGN-mediated vesicle trafficking is required for wax secretion from epidermal cells. Plant Physiol 164:1250–1260. https://doi.org/10.1104/pp.113.234583
McManus JFA (1948) Histological and histochemical uses of periodic acid. Stain Technol 23:99–108. https://doi.org/10.3109/10520294809106232
Melo MC, Borba EL, Paiva EAS (2010) Morphological and histological characterization of the osmophores and nectaries of four species of Acianthera (Orchidaceae: Pleurothallidinae). Plant Syst Evol 286:141–151. https://doi.org/10.1007/s00606-010-0294-1
Millner HJ, Baldwin TC (2016) Floral micromorphology of the genus Restrepia (Orchidaceae) and the potential consequences for pollination. Flora 225:10–19. https://doi.org/10.1016/j.flora.2016.09.007
Nepi M (2007) Nectary structure and ultrastructure. In: Nicolson SW, Nepi M, Pacini E (eds) Nectaries and nectar. Springer, Dordrecht, the Netherlands, pp 129–166
Nepi M, Stpiczyńska M (2007) Nectar resorption and translocation in Cucurbita pepo L. and Platanthera chlorantha Custer (Rchb.). Plant Biol (Stuttgart) 9:93–100. https://doi.org/10.1055/s-2006-924287
Nepi M, Stpiczyńska M (2008) Do plants dynamically regulate nectar features through sugar sensing? Plant Signal Behav 3:874–876. https://doi.org/10.4161/psb.3.10.6228
Nunes C, Castro M, Galetto L, Sazima M (2013) Anatomy of the floral nectary of ornithophilous Elleanthus brasiliensis (Orchidaceae: Sobralieae). Bot J Linn Soc 171:764–772. https://doi.org/10.1111/boj.12024
Pacek A, Stpiczyńska M, Davies K, Szymczak G (2012) Floral elaiophore structure in four representatives of the Ornithocephalus clade (Orchidaceae: Oncidiinae). Ann Bot 110:809–820. https://doi.org/10.1093/aob/mcs158
Pais MSS, Chaves das Neves HJ (1980) Sugar content of the nectary exudate of Epipactis atropurpurea Rafin. Apidologie 11:39–45. https://doi.org/10.1051/apido:19800105
Pais MS, Figueiredo ACS (1994) Floral nectaries from Limodorum abortivum (L) Sw and Epipactis atropurpurea Rafin (Orchidaceae): ultrastructural changes in plastids during the secretory process. Apidologie 25:615–626. https://doi.org/10.1051/apido:19940612
Pansarin ER, Pansarin LM, Martucci MEP, Gobbo-neto L (2016) Self-compatibility and specialisation in a fly-pollinated Acianthera (Orchidaceae: Pleurothallidiinae). Aust J Bot 64:359–367. https://doi.org/10.1071/BT15177
Pedersen MW, LeFevre CW, Wiebe HH (1958) Absorption of 14C-labelled sucrose by alfalfa nectaries. Science 127:758–759. https://doi.org/10.1126/science.127.3301.758-a
Poustka F, Irani NG, Feller A, Lu Y, Pourcel L, Frame K, Grotewold E (2007) A trafficking pathway for anthocyanins overlaps with the endoplasmic reticulum-to-vacuole protein-sorting route in Arabidopsis and contributes to the formation of vacuolar inclusions. Plant Physiol 145:1323–1335. https://doi.org/10.1104/pp.107.105064
Pridgeon AM, Stern WL (1983) Ultrastructure of osmophores in Restrepia (Orchidaceae). Am J Bot 70:1233–1243. https://doi.org/10.2307/2443293
Pridgeon AM, Stern WL (1985) Osmophores of Scaphosepalum (Orchidaceae). Bot Gaz 146:115–123. https://doi.org/10.1086/337505
Pridgeon AM, Solano R, Chase MW (2001) Phylogenetic relationships in Pleurothallidinae (Orchidaceae): combined evidence from nuclear and plastid DNA sequences. Am J Bot 88:2286–2308. https://doi.org/10.2307/3558390
Pridgeon AM, Cribb PJ, Chase MW, Rasmussen FN (2010) Genera Orchidacearum (vol. 4): Epidendroideae - part 1. Oxford University Press, New York, USA
Raguso RA (2004) Why are some floral nectars scented? Ecology 85:1486–1494. https://doi.org/10.1890/03-0410
Sakai WS (1973) Simple method for differential staining of paraffin embedded plant material using toluidine blue O. Stain Technol 48:247–249. https://doi.org/10.3109/10520297309116632
Shuel RW (1961) Influence of reproductive organs on secretion of sugars in flowers of Streptosolen jamesonii Miers. Plant Physiol 36:265–271. https://doi.org/10.1104/pp.36.2.265
Singer R, Cocucci A (1999) Pollination mechanism in four sympatric Southern Brazilian Epidendroideae orchids. Lindleyana 14:47–56. https://doi.org/10.1007/BF00984924
Singer RB, Flach A, Koehler S, Marsaioli AJ, Amaral MDCE (2004) Sexual mimicry in Mormolyca ringens (Lindl.) Schltr. (Orchidaceae: Maxillariinae). Ann Bot 93:755–762. https://doi.org/10.1093/aob/mch091
Solovchenko A (2010) Localization of screening pigments within plant cell and tissues. In: Solovchenko A (ed) Photoprotection in plants: optical screening-based mechanisms. Springer Verlag, Hildeberg, pp 67–70
Stpiczyńska M (1993) Anatomy and ultrastructure of osmophores of Cymbidium tracyanum Rolfe (Orchidaceae). Acta Soc Bot Pol 62:5–9. https://doi.org/10.5586/asbp.1993.001
Stpiczyńska M (2001) Osmophores of the fragrant orchid Gymnadenia conopsea L. (Orchidaceae). Acta Soc Bot Pol 70:91–96. https://doi.org/10.5586/asbp.2001.012
Stpiczyńska M (2003) Incorporation of [3H] sucrose after the resorption of nectar from the spur of Platanthera chlorantha (Custer) Rchb. Can J Bot 81:927–932. https://doi.org/10.1139/b03-085
Tholl D, Kish CM, Orlova I, Sherman D, Gershenzon J, Pichersky E, Dudareva N (2004) Formation of monoterpenes in Antirrhinum majus and Clarkia breweri flowers involves heterodimeric geranyl diphosphate synthases. Plant Cell 16:977–992. https://doi.org/10.1105/tpc.020156
Urru I, Stensmyr MC, Hansson BC (2011) Pollination by brood-site deception. Phytochemistry 72:1655–1666. https://doi.org/10.1016/j.phytochem.2011.02.014
Van der Pijl L, Dodson CH (1966) Orchid flowers--their Pollination and Evolution. University of Miami Press, Coral Gables, Florida, USA
Vogel S (1990) The role of scent glands in pollination. Smithsonian Institute, Washington, USA
Wester P, Johnson SD, Pauw A (2019) Scent chemistry is key in the evolutionary transition between insect and mammal pollination in African pineapple lilies. New Phytol 222:1624–1637. https://doi.org/10.1111/nph.15671
Woodcock T, Larson BMH, Kevan PG, Inouye DW, Lunau K (2014) Flies and flowers II: floral attractants and rewards. J Pollinat Ecol 12:63–94. https://doi.org/10.26786/1920-7603(2014)5
Acknowledgements
P.C.G. thanks the staffs of Núcleo de Pesquisa Orquidário do Estado and Núcleo de Pesquisa em Anatomia, Instituto de Botânica, for assistance with cultivated material and histology laboratories, and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES–Brazil, 0588/12-1) for funding. “Science without Borders” (Brazilian CAPES/CNPq 0469-13-0) enabled P.C.G. to conduct part of this study’s TEM at the University of Saskatchewan, where A.R.D. held a Discovery Grant from NSERC of Canada for laboratory operation and supplies.
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Arévalo-Rodrigues, G., de Barros, F., Davis, A.R. et al. Floral glands in myophilous and sapromyophilous species of Pleurothallidinae (Epidendroideae, Orchidaceae)—osmophores, nectaries, and a unique sticky gland. Protoplasma 258, 1061–1076 (2021). https://doi.org/10.1007/s00709-021-01624-2
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DOI: https://doi.org/10.1007/s00709-021-01624-2