Gynodioecy and floral dimorphism of Glechoma longituba (Nakai) Kuprian. (Lamiaceae) in Korea

  • Jang, Tae-Soo (Laboratory of Plant Systematics, Department of Biology and Institute of Basic Sciences, Kyung Hee University) ;
  • Hong, Suk-Pyo (Laboratory of Plant Systematics, Department of Biology and Institute of Basic Sciences, Kyung Hee University)
  • Received : 2011.08.29
  • Accepted : 2011.09.18
  • Published : 2011.09.30

Abstract

The present study was focused on the careful investigation of Glechoma longituba flowers collected from four populations in Korea to clarify their precise sexual systems. All floral characters of this taxon were examined by using a stereo microscopy. The nutlet size and production were compared between two distinct morphs (i.e., hermaphrodites and females), and pollen viability test of hermaphrodite and intermediate phenotype (i.e., individuals with a mixture of females and perfect flowers) was also observed by light microscopy (LM). All of the investigated floral characters of G. longituba are significantly different from one sexual morph to another. Hermaphroditic plants were larger than the female ones in corolla width and length, calyx length, filament length, anther length, and style length (all P < 0.0001, respectively). However, the nutlet width of the female plants was larger than those of the hermaphrodites (P = 0.013). Nutlet production of females was higher than hermaphrodites in Na-Ju population [H (Hermaphrodite): ca. 17.76%, F (Female): ca. 37.45%], but in Mun-San population was no significant difference between these sexual morphs (H: ca. 57.52%, F: ca. 53.16%). We have found significant differences between the fertile pollen grain of hermaphrodite and sterile pollen grain of intermediate phenotype based on pollen size and viability. The results of the present study suggest that compensation (flower size dimorphism, seed set, and pollen viability) is one of the main mechanisms in order to maintain female plants in gynodioecious G. longituba.

Keywords

References

  1. Agren, J. and M. F. Willson. 1991. Gender variation and sexual differences in reproductive characters and seed production in gynodioecious Geranium maculatum. Am. J. Bot. 78: 470-480. https://doi.org/10.2307/2445256
  2. Bai, Y.-P., Y.-W. Zhang, R. W. Gituru, J.-M. Zhao, and J.-D. Li. 2011. Sexual differences in reproductive characters and pollinator attractiveness in gynodioecious Glechoma longituba (Lamiaceae). Plant Spec. Biol. 26: 33-42. https://doi.org/10.1111/j.1442-1984.2010.00298.x
  3. Baker, H. G. 1948. Corolla-size in gynodioecious and gynomonoecious species of flowering plants. Proc. Leeds Philos. Lit. Soc. 5: 136-139.
  4. Charlesworth, B. and D. Charlesworth. 1978. A model for the evolution of dioecy and gynodioecy. Am. Naturalist 112: 975-997. https://doi.org/10.1086/283342
  5. Darwin, C. R. 1877. The different forms of flowers on plants of the same species. Murray, London.
  6. Delph, L. F. 1996. Flower size dimorphism in plants with unisexual flowers. In Floral biology: Studies on floral evolution in animal-pollinated plants. D. G. Lloyd and S. C. H. Barrett (eds.). Chapman and Hall, New York, Pp. 217-237.
  7. Delph, L. F. and D. G. Lloyd. 1991. Environmental and genetic control of gender in the dimorphic shrub Hebe subalpina. Evolution 45: 1957-1964. https://doi.org/10.2307/2409844
  8. Eckhart, V. M. 1999. Sexual dimorphism in flowers and inflorescences. In Gender and sexual dimorphism in flowering plants. M. A. Geber, T. E. Dawson and L. F. Delph (eds.). Springer, Berlin. Pp. 123-148.
  9. Harley, R. M., S. Atkins, A. L. Budantev, P. D. Cantino, B. J. Conn, R. Grayer, M. M. Harley, R. De Kok, T. Krestovskaja, R. Morales, A. J. Paton, O. Ryding and T. Upson. 2004. Labiatae. In Flowering plants, dicotyledons: Lamiales (except Acanthaceae including Avicenniaceae). J. W. Kaderoeit (ed.). Springer, Berlin, Pp. 167-275.
  10. Hong, S.-P. and H.-K. Moon. 2003. Gynodioecy in Lycopus maackianus Makino (Lamiaceae) in Korea: floral dimorphism and nutlet production. Flora 198: 461-467. https://doi.org/10.1078/0367-2530-00119
  11. Jang, T.-S. 2008. Systematics of the genus Glechoma L. and related genera (Nepetinae, Lamiaceae). M.Sci. Thesis, Kyung Hee University, Seoul, Korea.
  12. Jang, T.-S. and S.-P. Hong. 2010. Comparative pollen morphology of Glechoma and Marmoritis (Nepetinae, Lamiaceae). J. Syst. Evol. 48: 464-473. https://doi.org/10.1111/j.1759-6831.2010.00101.x
  13. Kawakubo, N. 1994. Gynodioecy in Cirsium chikushiense Koidz. (Compositae). Ann. Bot. 74: 357-364. https://doi.org/10.1006/anbo.1994.1128
  14. Koelewijn, H. P. and J. M. M. Van Damme. 1996. Gender variation, partial male sterility and labile sex expression in gynodioecious Plantago coronopus. New Phytol. 132: 67-76. https://doi.org/10.1111/j.1469-8137.1996.tb04510.x
  15. Krohne, D. T., I. Baker and H. G. Baker. 1980. The maintenance of the gynodioecious breeding system in Plantago lanceolata L. Am. Midl. Naturalist 103: 269-279. https://doi.org/10.2307/2424625
  16. Lafuma, L. and S. Maurice. 2006. Reproductive characters in a gynodioecious species, Silene italica (Caryophyllaceae), with attention to the gynomonoecious phenotype. Biol. J. Linn. Soc. 87: 583-591. https://doi.org/10.1111/j.1095-8312.2006.00597.x
  17. Lloyd, D. G. and C. J. Webb. 1977. Secondary sex characters in plants. Bot. Rev. 43: 177-216. https://doi.org/10.1007/BF02860717
  18. Miller, J. S. and D. L. Venable. 2003. Floral morphometrics and the evolution of sexual dimorphism in Lycium (Solanaceae). Evolution 57: 74-86.
  19. Owens, S. J. and J. L. Ubera-Jimènez. 1992. Breeding systems in Labiatae. In Advances in Labiate Science. R. M. Harley and T. Reynolds (eds.). Royal Botanic Gardens, Kew, Pp. 257-280.
  20. Rodriguez-Riano, T. and A. Dafni. 2007. Pollen-stigma interference in two gynodioecious species of Lamiaceae with intermediate individuals. Ann. Bot. 100: 423-431. https://doi.org/10.1093/aob/mcl168
  21. Ross, M. D. 1977. The evolution of gynodioecy and subdioecy. Evolution 32: 174-188.
  22. Shykoff, J. A., S. O. Kolokotronis, C. L. Collin and L. V. Manuela. 2003. Effects of male sterility on reproductive traits in gynodioecious plants: a meta-analysis. Oecologia 135: 1-9.
  23. Slade, A. J. and M. J. Hutchings. 1989. Within- and between population variation in ramet behaviour in the gynodioecious clonal herb, Glechoma hederacea (Labiatae). Can. J. Bot. 67: 633-639. https://doi.org/10.1139/b89-085
  24. Spira, T. P. 1980. Floral parameters, breeding system and pollinator type in Trichostema (Labiatae). Am. J. Bot. 67: 278-284. https://doi.org/10.2307/2442337
  25. Sun, M. and F. R. Ganders. 1986. Female frequencies in gynodioecious populations correlated with selfing rates in hermaphrodites. Am. J. Bot. 73: 1645-1648. https://doi.org/10.2307/2443933
  26. Thompson, J. D., A. G. Rolland and F. Prugnolle. 2002. Genetic variation for sexual dimorphism in flower size within and between populations of gynodioecious Thymus vulgaris. J. Evol. Bio. 15: 362-372. https://doi.org/10.1046/j.1420-9101.2002.00407.x
  27. Ubera-Jiménez, J. L. and P. J. Hidalgo-Fernández. 1992. Temporal Gynodioecy in Rosmarinus officinalis. In Advances in Labiate Science. R. M. Harley and T. Reynolds (eds.). Royal Botanic Gardens, Kew, Pp. 281-289.
  28. Van Damme, J. M. N. and W. Van Delden. 1984. Gynodioecy in Plantago lanceolata L. IV. Fitness components of sex types in different life cycle stages. Evolution 38: 1326-1336. https://doi.org/10.2307/2408638
  29. Widen, M. 1992. Sexual reproduction in a clonal gynodioecious herb Glechoma hederacea. Oikos 63: 430-438. https://doi.org/10.2307/3544969
  30. Widen, B. and M. Widén. 1999. Sex expression in the clonal gynodioecious herb Glechoma hederacea (Lamiaceae). Can. J. Bot. 77: 1689-1698. https://doi.org/10.1139/cjb-77-12-1689
  31. Zhang, Y.-W., C.-F. Yang and W. R. Gituru. 2008a. Within-season adjustment of sex expression in females and hermaphrodites of the clonal gynodioecious herb Glechoma longituba (Lamiaceae). Ecol. Res. 23: 873-881. https://doi.org/10.1007/s11284-007-0451-3
  32. Zhang, Y.-W., Y. Wang, Q. Yu and J.-M. Zhao. 2008b. Sex expression, female frequency, and reproductive output in a gynodioecious clonal herb, Glechoma longituba (Lamiaceae). Plant Ecol. 199: 255-264. https://doi.org/10.1007/s11258-008-9430-1
  33. Zhang, Y.-W., J.-M. Zhao and Y. Wang. 2011. The dynamics of pollen removal and deposition, and its effects on sexual phases in a protandrous plant: Glechoma longituba (Lamiaceae). Nord. J. Bot. 29: 105-111. https://doi.org/10.1111/j.1756-1051.2010.00798.x