Abstract
Plants of a heterosporous fern, Isoëtes, were collected from a wetland in Pu Rodet Leu, Mondulkiri, Cambodia, in which the flora has not yet been well studied. The characteristics of this quillwort, for example, dimorphic megaspores and small tuberculate ornamentation, were congruent with those of Isoëtes coromandelina L. f. subsp. coromandelina. Unlike most Isoëtes endemic species, this subspecies has a wide geographical range across India and the neighboring regions, and another subspecies, I. coromandelina subsp. macrotuberculata Marsden, grows in Australia. We have provided detailed characteristics for the first record of an Isoëtes species in Cambodia. Moreover, megaspore morphological features and the sequence of the chloroplast trnL intron were investigated to verify infraspecific and regional variation within this species, using specimens from India (Rajasthan and Varanasi), Sri Lanka, and Australia. Dimorphic megaspores were observed in similar proportions in a megasporangium of the Cambodian plant; the large spherical type averaged 378.5 μm in height in 409 megaspores, and the small flattened type averaged 227.7 μm in height in 544 megaspores. Microspores were not observed. The Cambodian Isoëtes plant is a tetrapolyploid (2n = 44 + 1). The morphological characteristics of the Cambodian quillwort are closer to those of a plant from Varanasi, India, than to those of plants from other regions in terms of tubercle size on the megaspore surface and polyploidy of chromosomes. Three haplotypes of the trnL intron showed regional specificity according to the country. However, the phylogenetic monophyly of all the plants examined was supported among the phylogeny of the entire Isoëtes genus. This close molecular relationship indicates that a recent dispersal of I. coromandelina may be related to its present distribution.
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References
Abraham A, Ninan CA (1958) Cytology of Isoetes. Curr Sci 27:60–61
Chandra S, Fraser-Jenkins CR, Kumari A, Srivastava A (2008) A summary of the status of threatened pteridophytes of India. Taiwania 53:170–209
Chen DH, Ronald PC (1999) A rapid DNA minipreparation method suitable for AFLP and other PCR applications. Plant Mol Biol Rep 17:53–57
Chen JM, Liu F, Gituru WR, Wang QF (2008) Chloroplast DNA phylogeography of the Chinese endemic alpine quillwort Isoetes hypsophila Hand.-Mazz. (Isoetaceae). Int J Plant Sci 169:792–798
Choi H-K, Jung J, Kim C (2008) Two new species of Isoetes (Isoetaceae) from Jeju Island, South Korea. J Plant Biol 51:354–358
Daltry JC (2008) Cambodia’s biodiversity revealed. Cambodian J Nat Hist 1:3–5
Ekstrand H (1920) Über die mikrosporenbildung von Isoetes echinosporum. Svensk Bot Tidskr 14:312–318
Hickey RJ (1984) Chromosome numbers of neotropical Isoëtes. Am Fern J 74:9–13
Hickey RJ (1986) Isoëtes megaspore surface morphology: nomenclature, variation, and systematic importance. Am Fern J 76:1–16
Hoot SB, Taylor WC, Napier NS (2006) Phylogeny and biogeography of Isoëtes (Isoëtaceae) based on nuclear and chloroplast DNA sequence data. Syst Bot 31:449–460
Kim C, Bounphanmy S, Sun BY, Choi H-K (2010a) Isoëtes laosiensis, a new species from Lao PDR. Am Fern J 100:45–53
Kim C, Shin H, Chang Y-T, Choi H-K (2010b) Speciation pathway of Isoëtes (Isoëtaceae) in East Asia inferred from molecular phylogenetic relationships. Am J Bot 97:958–969
Lindsay S, Middleton DJ (2012) Ferns of Thailand, Laos and Cambodia. http://rbg-web2.rbge.org.uk/thaiferns/. Accessed 11 Jan 2013
Marsden CR (1976) A new subspecies of Isoetes coromandelina from northern Australia. Contrib Herb Aust 24:1–10
Merrill ED, Perry LM (1940) A new Philippine Isoetes. Am Fern J 30:18–20
Newman M, Ketphanh S, Svengsuksa B, Thomas P, Sengdala K, Lamxay V, Armstrong K (2007) A checklist of the vascular plants of Lao PDR. Royal Botanic Garden Edinburgh, Edinburgh
Ninan CA (1958) Studies on the cytology and phylogeny of pteridophytes V. Observations on the Isoetaceae. J Indian Bot Soc 37:93–103
Pant DD, Srivastava GK (1962) The genus Isoetes L. in India. Proc Natl Acad Sci India B 28:242–280
Pant DD, Srivastava GK (1965) Cytology and reproduction of some Indian species of Isoetes. Cytologia 30:239–251
Pfeiffer NE (1922) Monograph of the Isoetaceae. Ann Mo Bot Gard 9:79–233
Retallack GJ (1997) Earliest Triassic origin of Isoetes and quillwort evolutionary radiation. J Paleontol 71:500–521
Rydin C, Wikström N (2002) Phylogeny of Isoëtes (Lycopsida): resolving basal relationships using rbcL sequences. Taxon 51:83–89
Shukla PK, Srivastava GK, Shukla SK (2002) The quillworts (Isoetes) of India: distribution, endemism and species radiation. Biodivers Conserv 11:959–973
Shukla PK, Srivastava GK, Shukla SK, Rajagopal PK (2005) Two new species of the genus Isoetes L. (Isoetaceae-Lycopsida) from India. Taxon 54:109–116
Srivastava GK, Srivastava M, Shukla PK (1997) Quillworts of Pachmarhi Hills, Central India. Indian Fern J 14:38–50
Srivastava GK, Rai M, Srivastava M (2003) Cytomorphological studies on some Indian population of Isoëtes coromandelina L. f. In: Chandra S, Srivastava M (eds) Pteridology in the New Millennium. Kluwer Academic Publishers, New Delhi, pp 191–203
Thompson JD, Gibson TJ, Plewniak F, Jeanmougin F, Higgins DG (1997) The CLUSTAL_X Windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. Nucl Acids Res 25:4876–4882
Verma SC (1961) Cytology of Isoetes coromandelina. Amer Fern J 51:99–104
Acknowledgments
We thank Dr. Germinal Rouhan (Museum National d’Histoire Naturelle, P), Dr. Sarah Hirst (Department of Land Resource Management, DNA), and Dr. James C. Solomon (Missouri Botanical Garden, MO) for assistance in studying the specimens. The field collection by H. Won in Cambodia was supported by the National Institute of Biological Resources (NIBR), Ministry of Environment, South Korea. This study was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government [Ministry of Education, Science, and Technology (MEST)] (NRF-2011-0016929).
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606_2013_858_MOESM1_ESM.jpg
Fig. S1. Representation of dimorphism in megaspores of Isoëtes coromandelina L. f. subsp. coromandelina from Mondulkiri, Cambodia. A scattered plot of diameter versus height was generated using 953 megaspores in a megasporangium. Open circles (○) and closed circles (●) indicate large spherical type (409 megaspores) and small flattened type (544 megaspores), respectively (JPEG 515 kb)
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Jung, J., Ryu, Y., Won, H. et al. Morphological and molecular characterization of a new record of Isoëtes coromandelina subsp. coromandelina from Cambodia. Plant Syst Evol 300, 43–50 (2014). https://doi.org/10.1007/s00606-013-0858-y
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DOI: https://doi.org/10.1007/s00606-013-0858-y