Journal of Plant Research

, Volume 117, Issue 4, pp 265–276 | Cite as

Correlation between pollen morphology and pollination mechanisms in the Hydrocharitaceae

Original Article

Abstract

The pollen morphology of 11 genera and 11 species of the Hydrocharitaceae and one species of the Najadaceae was studied using scanning and transmission electron microscopies, and the exine structures and sculptures are discussed in relation to pollination mechanisms and the molecular phylogeny. The pollen grains of the Hydrocharitaceae are spherical, inaperturate, and form monads or tetrads, while those of the Najadaceae are elliptical, inaperturate, and form monads. The entomophilous genera Egeria, Blyxa, Ottelia, Stratiotes, and Hydrocharis share pollen grains that have projections like spines or bacula. The anemophilous genus Limnobium has reticulate pollen grains. The hypohydrophilous genera Thalassia and Najas are characterized by pollen grains with reduced exine structures. The pollen-epihydrophilous genera Elodea and Hydrilla have tightly arranged small spinous pollen grains, and the male flower-epihydrophilous genera Enhalus and Vallisneria have reduced reticulate or gemmate exines. Character state reconstruction of the exine structures and sculptures using a molecular phylogenetic tree suggests that variation in the exine is generally correlated with the pollination mechanism; the selective pressures acting on the pollination mechanisms have reduced the exine structure in hypohydrophilous plants and resulted in various exine sculptures that are adapted to the different pollination mechanisms in entomophilous, anemophilous, and pollen-epihydrophilous plants.

Keywords

Exine Hydrocharitaceae Hydrophily Phylogeny Pollen Pollination 

References

  1. Angiosperm Phylogeny Group (2003) An update of the angiosperm phylogeny group classification for the orders and families of flowering plants: APG II. Bot J Linn Soc 141:399–436Google Scholar
  2. Cook CDK (1982) Pollination mechanisms in the Hydrocharitaceae. In: Symoens JJ, Hooper SS, Compere P (eds) Studies on aquatic vascular plants. Royal Botanical Society of Belgium, Brussels, pp 1–15Google Scholar
  3. Cook CDK (1985) A revision of the genus Apalanthe (Hydrocharitaceae). Aquat Bot 21:157–164CrossRefGoogle Scholar
  4. Cook CDK (1988) Wind pollination in aquatic angiosperms. Ann Mo Bot Gard 75:768–777Google Scholar
  5. Cook CDK (1996) Aquatic plant book. SPB, AmsterdamGoogle Scholar
  6. Cook CDK, Luond R (1982a) A revision of the genus Nechamandra (Hydrocharitaceae). Aquat Bot 13:505–513CrossRefGoogle Scholar
  7. Cook CDK, Luond R (1982b) A revision of the genus Hydrocharis (Hydrocharitaceae). Aquat Bot 14:177–204CrossRefGoogle Scholar
  8. Cook CDK, Luond R (1983) A revision of the genus Blyxa (Hydrocharitaceae). Aquat Bot 15:1–52CrossRefGoogle Scholar
  9. Cook CDK, Urmi-Koenig K (1983) A revision of the genus Limnobium including Hydromystria (Hydrocharitaceae). Aquat Bot 17:1–27CrossRefGoogle Scholar
  10. Cook CDK, Urmi-Koenig K (1984) A revision of the genus Egeria (Hydrocharitaceae). Aquat Bot 19:73–96CrossRefGoogle Scholar
  11. Cook CDK, Urmi-Koenig K (1985) A revision of the genus Elodea (Hydrocharitaceae). Aquat Bot 21:111–156CrossRefGoogle Scholar
  12. Cook CDK, Symoens J, Urmi-Koenig K (1984) A revision of the genus Ottelia (Hydrocharitaceae). I. Generic considerations. Aquat Bot 18:263–274CrossRefGoogle Scholar
  13. Crane PR, Fris EM, Pedersen KR (1995) The origin and early diversification of angiosperms. Nature 374:27–33Google Scholar
  14. Dahlgren RMT, Clifford HT, Yeo PF (1985) The families of the monocotyledons. Structure, evolution, and taxonomy. Springer, Berlin Heidelberg New YorkGoogle Scholar
  15. Erdtman G (1960) The acetolysis method. A revised description. Sven Bot Tidskr 54:561–564Google Scholar
  16. Furness CA, Rudall PJ (1999) Inaperturate pollen in Monocotyledons. Int J Plant Sci 160:395–414CrossRefGoogle Scholar
  17. Grayum MH (1992) Comparative external pollen ultrastructure of the Araceae and putatively related taxa. Missouri Botanical Garden, St. Louis, MissouriGoogle Scholar
  18. Harley MM, Kurmann MH, Ferguson IK (1991) Systematic implications of comparative morphology in selected Tertiary and extant pollen from the Palmae and the Sapotaceae. Pollen Spores 44:225–238Google Scholar
  19. Heslop-Harrison J (1976) The adaptive significance of the exine. In: Ferguson IK, Muller J (eds) The evolutionary significance of the exine. Linnean Society Symposium Series 1. The Linnean Society of London, London, pp 27–37Google Scholar
  20. Hesse M (2000) Pollen wall stratification and pollination. Plant Syst Evol 222:1–17Google Scholar
  21. Karnovsky MJ (1965) A formaldehyde-glutaraldehyde fixative of high osmolality for use in electron microscopy. J Cell Biol 27:137A–138AGoogle Scholar
  22. Kaul RB (1970) Evolution and adaptation of inflorescences in the Hydrocharitaceae. Am J Bot 57:708–715Google Scholar
  23. Kress WJ (1986) Exineless pollen structure and pollination systems of tropical Heliconia (Heliconiaceae). In: Blackmore S, Ferguson IK (eds) Pollen and spores: form and function. The Linnean Society of London, London, pp 329–345Google Scholar
  24. Kress WJ, Stone DE (1978) Ultrastructure of exine-less pollen; Heliconia (Heliconiaceae). Am J Bot 65:1064–1076Google Scholar
  25. Les DH, Cleland MA, Waycott M (1997) Phylogenetic studies in Alismatidae. II. Evolution of marine angiosperms (seagrasses) and hydrophily. Syst Bot 22:1–21Google Scholar
  26. Madisson WP, Maddison DR (1992) MacClade: analysis of phylogeny and character evolution. Version 3.0. Sinauer, Sunderland, Mass.Google Scholar
  27. Mayo SJ, Bogner J, Boyce PC (1997) The genera of Araceae. Royal Botanic Gardens, KewGoogle Scholar
  28. Nilsson S (1990) Taxonomic and evolutionary significance of pollen morphology in the Apocynaceae. Plant Syst Evol 5[Suppl]:91–102Google Scholar
  29. Pettitt JM (1980) Reproduction in seagrass: nature of the pollen and receptive surface of the stigma in the Hydrocharitaceae. Ann Bot 45:257–271Google Scholar
  30. Pettitt JM (1981) Reproduction in seagrasses: pollen development in Thalassia hemprighii, Halophila stipulacea and Thalassodendron ciliatum. Ann Bot 48:609–622Google Scholar
  31. Pettitt JM, Jermy AC (1975) Pollen in hydrophilous angiosperms. Micron 5:377–405CrossRefGoogle Scholar
  32. Proctor M, Yeo P, Lack A (1996) The natural history of pollination. Harper Collins, LondonGoogle Scholar
  33. Scribailo RW, Posluszny U (1984) The reproductive biology of Hydrocharis morsus-ranae. I. Floral biology. Can J Bot 62:2779–2787Google Scholar
  34. Skvarla JJ, Rowley JR (1970) The pollen wall of Canna and its similarity to the germinal apertures of other pollen. Am J Bot 57: 519–529Google Scholar
  35. Spurr AR (1969) A low-viscosity epoxy resin embedding medium for electron microscopy. J Ultrastruct Res 26:31–43PubMedGoogle Scholar
  36. Takahashi M (1982) Pollen morphology in North American species of Trillium. Am J Bot 69:1185–1195Google Scholar
  37. Takahashi M (1983) Pollen morphology in Asiatic species of Trillium. Bot Mag (Tokyo) 96:377–384Google Scholar
  38. Takahashi M (1987) Development of omniaperturate pollen in Trillium kamtchaticum (Liliaceae). Am J Bot 74:1842–1852Google Scholar
  39. Takahashi M (1994) Pollen development in a submerged plant, Ottelia aismoides (L. ) Pers. (Hydrocharitaceae). J Plant Res 107:161–164Google Scholar
  40. Takahashi M (1995) Development of structure-less pollen wall in Ceratophyllum demersum L. (Ceratophyllaceae). J Plant Res 108:205–208Google Scholar
  41. Tanaka N (2000) Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains. Ann Tsukuba Bot Gard 19:7–12Google Scholar
  42. Tanaka N (2003) Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains. II. Air bubbles cause the male flower to surface. Ann Tsukuba Bot Gard 22:11–13Google Scholar
  43. Tanaka N, Setoguchi H, Murata J (1997) Phylogeny of the family Hydrocharitaceae inferred from rbcL and matK gene sequence data. J Plant Res 110:329–337Google Scholar
  44. Verhoeven JTA (1979) The ecology of Ruppia dominated communities in western Europe. I. Distribution of Ruppia representatives in relation to their autecology. Aquat Bot 6:197–268CrossRefGoogle Scholar
  45. Walker JW (1976) Evolutionary significance of the exine in the pollen of primitive angiosperms. In: Ferguson IK, Muller J (eds) The evolutionary significance of the exine. Linnean Symposium Society Series 1. Academic, New York, pp 251–308Google Scholar
  46. Whitehead DR (1968) Wind pollination in the angiosperms: evolutionary and environmental considerations. Evolution 23:28–35Google Scholar
  47. Wodehouse RP (1935) Pollen grains. McGraw-Hill, New YorkGoogle Scholar
  48. Zavada MS (1983) Comparative morphology of monocot pollen and evolutionary trends of apertures and wall structures. Bot Rev 49:331–379Google Scholar

Copyright information

© The Botanical Society of Japan and Springer-Verlag  2004

Authors and Affiliations

  1. 1.Tsukuba Botanical GardenNational Science MuseumTsukuba 305-0005Japan
  2. 2.Laboratory of Plant Morphology, Faculty of HorticultureChiba UniversityChibaJapan
  3. 3.Botanical Gardens, Graduate School of ScienceUniversity of TokyoTokyoJapan

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