Abstract
Chromosome traits may differ between closely related ferns growing in different geological landscapes. Adiantum series Gravesiana (Pteridaceae) includes six species, of which, five species are exclusively distributed in Karst landforms, and one, Adiantum juxtapositum, grows on Danxia landform. Additionally, there are some populations or individuals whose morphology are between different species, which may be the results of polyploidization or hybridization. Here we studied chromosome numbers of species in series Gravesiana primarily using crosiers. Results are: A. longzhouensis and A. juxtapositum were diploids with 2n = 60 and 2n = 64, respectively; A. dentatum was deduced to be diploids with 2n = ca. 60; A. mariesii had two cytotypes, 2n = 60 (diploid) and 2n = ca. 120 (tetraploid), respectively; A. gravesii had four cytotypes including 2n = ca. 60 (diploid), ca. 120 (tetraploid), ca. 150 (pentaploid), and ca. 180 (hexaploid). All these different cytotypes suggest polyploidization and hybridization have occurred in A. gravesii and A. mariesii, so we treated these two species as two “complex group”. All chromosome numbers in this study are the first record.
References
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Bir, S.S. & Verma, S.C. (2010) <em>Chromosome atlas of the Indian pteridophytes (1951–2009)</em>. Bishen Singh Mahendra Pal Singh, Dehra Dun, 111–129.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">de Peer, Y.V., Ashman, T.L., Soltis, P.S. & Soltis, D.E. (2021) Polyploidy: an evolutionary and ecological force in stressful times. <em>The Plant Cell</em> 33: 11–26. https://doi.org/10.1093/plcell/koaa015</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Cao, J., Yuan, D. & Pan, G. (2003) Some soil features in Karst ecosystem. <em>Advance in Earth Science</em> 18: 37–44.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Cheng, X. & Zhang, S.Z. (2010) Index to chromosome numbers of Chinese pteridophyta (1969–2009). <em>Journal of Fairylake Botanical Garden</em> 9: 1–58.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Dong, S.Y. (2011) Taxonomic Studies on <em>Asplenium</em> sect. <em>Thamnopteris </em>(Aspleniaceae) I: Cytological Observations. <em>American Fern Journal</em> 101: 156–171. https://doi.org/10.1640/0002-8444-101.3.156</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Glick, L. & Mayrose, I. (2014) ChromEvol: assessing the pattern of chromosome number evolution and the inference of polyploidy along a phylogeny. <em>Molecular Biology and Evolution</em> 31: 1914–1922. https://doi.org/10.1093/molbev/msu122</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Guerra, M. (2008) Chromosome numbers in plant cytotaxonomy: concepts and implications. <em>Cytogenetic and Genome Research</em> 120: 339–350. https://doi.org/10.1159/000121083</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">He, Z., Yan, Y., Ma, Q. & Lu, Q. (2012) The bryophyte diversity of the Danxia landform in Hunan, China. <em>Biodiversity Science</em> 20: 522–526. https://doi.org/10.3724/SP.J.1003.2012.05216</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Hsieh, T.H., Chang, Y.H., Chiou, W.L. & Huang, Y.M. (2008) Chromosome Numbers of Five Species of the Marattiaceae in Taiwan. <em>Taiwan Journal of Forest Science</em> 23: 377–381.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Irudayaraj, V. & Manickam, V.S. (1987) SOCGI plant chromosome number reports—V.<em> Journal of Cytology and Genetics</em> 22: 156–163.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Kato, M., Nakato, N., Cheng, X. & Iwatsuki, K. (1992) Cytotaxonomic Study of Ferns of Yunnan, Southwestern China. <em>The Botanical Magazine, Tokyo</em> 105: 105–124. https://doi.org/10.1007/BF02489407</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Li, Y.B., Wang, S.J. & Li, R.L. (2004) Some soil features of karst ecosystem.<em> Ecology and Environment</em> 13: 434–438.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Liu, C.C., Liu, Y.G., Guo, K., Fan, D.Y., Li, G.W., Zheng, Y.R., Yu, L.F. & Yang, R. (2011) Effect of drought on pigments, osmotic adjustment and antioxidant enzymes in six woody plant species in karst habitats of southwestern China. <em>Environment and Experimental Botany</em> 71: 174–183. https://doi.org/10.1016/j.envexpbot.2010.11.012</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Liu, Y., Liu, C., Rubinato, M., Guo, K., Zhou, J. & Cui, M. (2020) An Assessment of Soil’s Nutrient Deficiencies and Their Influence on the Restoration of Degraded Karst Vegetation in Southwest China.<em> Forests </em>11: 797. https://doi.org/10.3390/f11080797</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Liu, Y.G., Liu, C.C., Wang, S.J., Guo, K., Yang, J., Zhang, X.S. & Li, G.Q. (2013) Organic carbon storage in four ecosystem types in the karst region of southwestern China. <em>PLoS ONE </em>8:e56443. https://doi.org/10.1371/journal.pone.0056443</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Manickam, V.S. & Irudayaraj, V. (1988) <em>Cytology of ferns of the Western Ghats (South India)</em>. Today and Tomorrow’s Printers and Publishers, New Delhi, pp. 81.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Manton, I., Sinha, B.M.B. & Vida, G. (1970) Cytotaxonomic studies in the <em>Adiantum caudatum</em> complex of Africa and Asia II. Autoploidy and alloploidy in African representaties of <em>A. incisum</em>. <em>Botanical Journal of the Linnean Society</em> 63: 1–21. [With 3 plates and 7 figures] https://doi.org/10.1111/j.1095-8339.1970.tb02299.x</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Mehra, P.N. & Verma, S.C. (1960) Cytotaxonomic Observations on Some West Himalayan Pteridaceae. <em>Caryologia</em> 13: 619–650. https://doi.org/10.1080/00087114.1960.10797101</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Nakato, N. & Kato, M. (2005) Cytogeography of the <em>Adiantum pedatum</em> complex (Pteridaceae, subfamily Adiantoideae). <em>Acta Phytotaxonomica et Geobotanica</em> 56: 85–96.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Paris, C.A. (1993) <em>Adiantum</em>.<em> In: </em>Flora of North America Edit. Comitt. (ed.) <em>Flora of North America, North of Mexico. </em>Vo1. 2. Pteridophytes and Gyrnnosperms, Oxford University Press, New York, pp. 125–130.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Paris, C.A. & Windham, M.D. (1988) A biosystematics investigation of the<em> Adiantum pedatum</em> complex in eastern North America. <em>Systematic Botany</em> 13: 240–255. https://doi.org/10.2307/2419103</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Perwati, L.K. & dan Purnomo, S. (2002) cytotaxonomy of <em>Adiantum</em> genus in Merapi Mountain, Lawu Mountain and Dieng Plateu. <em>Teknosains</em> 15: 379–390</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Pedro, J.S., Mario, R.M. & Claudio, P.R. (2006) Chromosome numbers of Chilean Pteridophytes: first contribution. <em>Gayana Botanica</em> 63: 115–118. https://doi.org/10.4067/S0717-66432006000100007</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Qi, X.P. & Zhang, X.C. (2011) Cytotaxonomic study of three species of <em>Lepisorus</em> from China (Polypodiaceae). <em>Guihaia</em> 31: 181–183.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Roy, R.P. & Sinha, B.M.B. (1961) Meiotic Studies in the Genus <em>Adiantum</em>. <em>Caryologia</em> 14: 413–428. https://doi.org/10.1080/00087114.1961.10796044</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Saggoo, M.I.S. & Kaur, M. (2016) Irregular Meiotic Behaviour in Maidenhair Fern Adiantum capillus-veneris L. from Northwest India.<em> Cytologia</em> 81: 77–82. https://doi.org/10.1508/cytologia.81.77</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Shao, W. (2013) Cytological methods in fern by using embryo and young sporophyte. <em>Acta Botanica Boreali-Occidentalia Sinica</em> 33: 407–410.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Shing, K.H. & Wu, S.K. (1990) Adiantaceae.<em> In: </em>Ching, R.C. & Shing, K.H. (eds.)<em> Flora Republicae Popularis Sinicae, 3 (1)</em>. Science Press, Beijing, 173–216.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Tindale, M.D. & Roy, S.K. (2002) A cytotaxonomic survey of the Pteridophyta of Australia. <em>Australian systematic botany</em> 15: 839–937. https://doi.org/10.1071/SB00034</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Vijayakanth, P., Sathish, S.S., Rajkumar, D.S., Irudayaraj, V., Kavitha, R. & Mazumdar, J. (2018) Studies on the chromosome numbers of ferns from Kolli Hills, Eastern Ghats, Tamil Nadu, India.<em> Caryologia</em> 71: 380–396. https://doi.org/10.1080/00087114.2018.1482151</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wagner, W.H. Jr & Boydsten, K.E. (1978) A dwarf coastal variety of maidenhair fern <em>Adiantum pedatum</em>. <em>Canadian Journal of Botany-revue canadienne de botanique</em> 56: 1726–1729. https://doi.org/10.1139/b78-204</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Walker, T.G. (1973) Evidence from cytology in the classification of ferns. <em>Botanical Journal of the Linnean Society</em> 67: 91–110.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wang, A.H., Zhang, W.W., Li, D.L., Li, X.W., Yan, Y.H., Wang, F.G. & Xing, F.W. (2017) Revision of series<em> Gravesiana</em> (<em>Adiantum </em>L.) based on morphologic characters and phylogeny analyses. <em>PLOS ONE</em> 12: e0172729. https://doi.org/10.1371/journal.pone.0172729</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wang, K.L. & Zhang, C.H. (1999) Vulnerable characteristics of ecosystem, environmental problems and comprehensive strategies for ecological construction in the karst mountainous region of west Hunan. <em>Journal of Mountain Research</em> 17: 30–35.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wang, R.X. (2011) Cytotaxonomic Study of 12 Species in the Polypodiaceae from Southern China. <em>American Fern Journal </em>101: 307–316. https://doi.org/10.1640/0002-8444-101.4.307</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wang, R.X., Liu, L., Shao, W., Liu, J. & Deng, X.C. (2013) Cytotaxonomic study on two species of the <em>Arthropteris</em> from Guangxi, China. <em>Guihaia</em> 33: 723–726.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wang, R.X., Lu, S.G. & Deng, X.C. (2007) Cytotaxonomic studies of the Chinese pteridophytes: A review. <em>Acta Phytotaxonomica Sinica</em> 45: 98–111. </span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wang, R.X., Shao, W., Bai, S.M. & Zhou, Z.P. (2018) Cytotaxonomic study of <em>Plagiogyria</em> (Plagiogyriaceae) from China. <em>Flora</em> 243: 53–57. https://doi.org/10.1016/j.flora.2018.04.004</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Windham, M.D. & Yatskievych, G. (2003) Chromosome studies of Cheilanthoid ferns (Pteridaceae: Cheilanthoideae) from the western United States and Mexico. <em>American Journal of Botany</em> 90: 1788–1800. https://doi.org/10.3732/ajb.90.12.1788</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Wu, Z.H. (1984) Cytology summary of Pteridophyte.<em> Guihaia</em> 4: 1–8.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Yan, Y.H., He, Z.X., Ma, Q.X., Zhou, X.L. & Lu, Q.Y. (2012) The pteridophyte diversity of the Danxia landform in Hunan Province, China. <em>Biodiversity Science</em> 20: 517–521. https://doi.org/10.3724/SP.J.1003.2012.05215</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Zhang, G.M., Liao, W.B., Ding, M.Y., Lin, Y.X., Wu, Z.H., Zhang, X.C., Dong, S.Y., Prado, J., Gilbert, M.G., Yatskievych, G.Y., Ranker, T.A., Hooper, E.A., Alverson, E.R., Metzgar, J.S., Funston, M., Masuyama, S. & Kato, M. (2013) Pteridaceae.<em> In: </em>Wu, Z.Y., Raven, P.H. & Hong, D.Y. (eds.)<em> Flora of China</em>,<em> Vols. 2–3</em>. Science Press, Beijing; Missouri Botanical Garden Press, St. Louis, pp. 169–256.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Zhang, X.B., Liu, X.M. & Bai, X.Y. (2011) Application of a <sup>137</sup>Cs fingerprinting technique for interpreting responses of sediment deposition of a karst depression to deforestation in the Guizhou Plateau, China. <em>Science China Earth Science</em> 54: 431–437. https://doi.org/10.1007/s11430-010-4105-x</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Zhang, X.B. & Wang, K.L. (2009) Ponderation on the shortage of mineral nutrients in the soil-vegetation ecosystem in carbonate rock-distributed mountain regions in southwest China. <em>Earth and Environment</em> 37: 337–341.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Zheng, X.J. & Kuang, H.W. (2021) The uncanny workmanship of nature—Yadan, Danxia and Karst. <em>Bulletin of Mineralogy, Petrology and Geochemistry</em> 40: 992–997.</span></span></span></p>
<p align="justify"><span style="color: #000000;"><span style="font-family: Times New Roman, serif;"><span style="font-size: small;">Zhou, L., Wang, X., Wang, Z., Zhang, X., Chen, C. & Liu, H. (2020) The challenge of soil loss control and vegetation restoration in the karst area of southwestern China. <em>International Soil and Water Conservation Research</em> 8: 26–34. https://doi.org/10.1016/j.iswcr.2019.12.001</span></span></span></p>