Plant species with extremely small populations (PSESP) in China: A seed and spore biology perspective

doi:10.1016/j.pld.2016.09.002

Abstract

Abstract: Approximately one fifth of the world's plants are at risk of extinction. Of these, a significant number exist as populations of few individuals, with limited distribution ranges and under enormous pressure due to habitat destruction. In China, these most-at-risk species are described as ‘plant species with extremely small populations’ (PSESP). Implementing conservation action for such listed species is urgent. Storing seeds is one of the main means of ex situ conservation for flowering plants. Spore storage could provide a simple and economical method for fern ex situ conservation. Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation. But what is known about the seed and spore biology (storage and germination) of at-risk species? We have used China's PSESP (the first group listing) as a case study to understand the gaps in knowledge on propagule biology of threatened plant species. We found that whilst germination information is available for 28 species (23% of PSESP), storage characteristics are only known for 8% of PSESP (10 species). Moreover, we estimate that 60% of the listed species may require cryopreservation for long-term storage. We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.

Key words: Threatened species, Orchids, Storage characteristics, Cryopreservation, ex situ conservation

Ellie Merrett Wade, Jayanthi Nadarajan, Xiangyun Yang, Daniel Ballesteros, Weibang Sun, Hugh W. Pritchard. Plant species with extremely small populations (PSESP) in China: A seed and spore biology perspective[J]. Plant Diversity, 2016, 38(05): 209-220.

References

Aragón, C.F., Pangua, E., 2004. Spore viability under different storage conditions in four rupicolous Asplenium L. taxa. Amer. Fern J. 941, 28-38.
Arditti, J., 1992. Fundamentals of Orchid Biology. John Wiley and Sons, New York, 691 pp.
Arditti, J., 1982. Orchid Biology: Reviews and Perspectives, vol. 2. Cornell University Press, USA, pp. 271-275.
Arditii, J. (Ed.), 1984. Orchid Biology: Reviews and Perspectives, vol. 3. Cornell University Press, USA, 432 pp.
Ballesteros, D., 2010. Conservation of fern spores. In: Kumar, A., Fernández, H., Revilla-Bahillo, A. (Eds.), Working with Ferns. Issues and Applications. Springer, New York, pp. 165-172.
Ballesteros, D., Estrelles, E., Walters, C., et al., 2011. Effect of storage temperature on green spore longevity for the ferns Equisetum ramosissimum and Osmunda regalis. CryoLetters 32, 89-98.
Ballesteros, D., Estrelles, E., Walters, C., et al., 2012. Effects of temperature and desiccation on ex situ conservation of non-green fern spores. Amer. J. Bot. 99, 721-729.
Bowling, J.C., Thompson, P.A., 1972. On storing orchid seed. Orchid. Rev. 80, 120-121.
Campbell, M.W., 1980. Plant Propagation for Reforestation in Nepal. Technical Note 1/80. Department of Forestry, Australian National University.
Cao, J.W., Liu, C.L., Zhang, B., et al., 2010. Seed germination of endangered Cathaya argyrophylla Chun & Kuang. Acta Ecol. Sin. 30, 4027-4034.
Cavender, N., Westwood, M., Bechtoldt, C., et al., 2015. Strengthening the conservation value of ex situ tree collections. Oryx 49, 416-424.
Chen, Z.L., Ye, X.L., Liang, C.Y., et al., 2004. Seed germination in vitro of Paphiopedilum armeniacum and P. micranthum. Acta Hort. Sinica 31, 540-542.
Cheng, G.Y., Tang, X.J., Gao, H.B., et al., 2004. Dormancy mechanism and relieving techniques of seeds of Taxus cuspidata Sieb et Zucc. J. Beijing For. Univ. 26, 5-10.
Cibrian-Jaramillo, A., Hird, A., Oleas, N., et al., 2013. What is the conservation value of a plant in a botanic garden? Using indicators to improve management of ex situ collections. Bot. Rev. 79, 559-577.
Corlett, R.T., 2016. Plant diversity in a changing world: status, trends and conservation needs. Plant Divers. 38, 10-16.
Dang, H.S., Zhang, Y.J., Jiang, M.X., et al., 2005. A preliminary study on dormancy and germination physiology of endangered species, Berchemiella wilsonii (Schneid.)
Nakai var. pubipetiolata H. Qian seeds. J. Wuhan. Bot. Res. 23, 327-331.
Dehgan, B., Schutzman, B., 1989. Embryo development and germination of cycas seeds. J. Amer. Soc. Hortic. Sci. 114, 125-129.
Ding, C.C., Zhang, T., Liu, F.Y., 2005. Rapid propagation of Cymbidium wenshanense Y.S.Wu et F.Y.Liu. J. Wenshan Teach. Coll. 18, 225-226.
Dirr, M.A., Heuser, C.W., 1987. The Reference Manual of Woody Plant Propagation.Varsity Press, Athens.
IUCN/SSC Cycad Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.
ix t 86 pp. In: Donaldson, J.S. (Ed.), 2003. Cycads. Status Survey and Conservation Action Plan.
Gordon, A.G., 1992. Seed Manual for Forest Trees. Forestry Commission Bulletin 83.Her Majesty's Stationery Office, London.
Gosling, P., 2007. Raising Trees and Shrubs from Seed Collection. Forestry Commission, Edinburgh.
Griffith, M.P., Calonje, M., Meerow, A.W., Tut, F., Kramer, A.T., Hird, A., 2015. Can a botanic garden cycad collection capture the genetic diversity in a wild population? Int. J. Plant Sci. 176, 1-10.
Gu, D.Z., Shen, H.M., Yan, Z.X., et al., 2015. Seedling and control technology of morphological development of seed embryonic of Taxus cuspidata Sieb. et Zucc.Hubei Agric. Sci. 2015-07.
Hasegawa, A., Goi, M., Sato, M., et al., 1978. Fundamental studies on the asymbiotic seed germination of Calanthe. Tech. Bull. Fac. Agric. Kagawa Univ. 29, 251-259.
Han, J.W., Zhang, Z.Y., Wang, E.M., et al., 2014. Pinus dabeshanensis seed characteristics and the promotion of seed germination. Chin. Agric. Sci. Bull. 30, 5-10.
Hay, F.R., Merritt, D.J., Soanes, J.A., et al., 2010. Comparative longevity of Australian orchid (Orchidaceae) seeds under experimental and low temperature storage conditions. Bot. J. Linn. Soc. 164, 26-41.
Hu, G.W., Lu, Y.J., Li, H.P., et al., 2012. Study on seed germination characters of Parrotia subaequalis. J. Zhejiang For. Sci. Tech 6, 48-51.
Ibars, A.M., Estrelles, E., 2012. Recent developments in ex situ and in situ conservation of ferns. Fern Gaz. 19, 67-86.
IUCN, 2015. The IUCN Red List of Threatened Species. http://www.iucnredlist.org.
Jian, S., Liu, N., Gao, Z., et al., 2006. Biological characteristics of wild Cycas fairylakea population in Guangdong Province, China. Front. Biol. China 1, 430-433.
Jøker, D., 2000. Pterocarpus Indicus. Seed Leaflet 37. University of Copenhagen.http://curis.ku.dk/ws/files/20648510/pterocarpus_indicus_int.pdf.
Krishnapillay, B., Marzalina, M., Alang, Z.C., 1994. Cryopreservation of whole seeds and excised embryos of Pterocarpus indicus. J. Trop. For. Sci. 7, 313-322.
Lai, J.Y., Huang, K.X., Pan, C.L., et al., 2007. Study on the seed storage and germination of Kmeria septentrionalis. Guangxi For. Sci. 36, 19-21.
Lan, Q.Y., Jiang, X.C., Song, S.Q., et al., 2007. Changes in germinability and desiccation-sensitivity of recalcitrant Hopea hainanensis Merr. et Chun seeds during development. Seed Sci. Technol 35, 21-31.
Lan, Y.T., Wei, X.L., Huang, L., et al., 2014. Study on technology of aseptic sowing and proliferation of protocorms in wild Geodorum eulophioides. J. Anhui Agri. Sci. 42, 395-397, 418.
Langkamp, P., Plaisted, M., 1987. Appendix 1. Native plant seed usage by the mining industry - a survey. In: Langkamp, P. (Ed.), Germination of Australian Native Plant Seed. Inkata Press, Melbourne, Sydney, pp. 135-181.
Le, X.W., Cui, M.Y., Yang, S.Z., et al., 2013. Characters on the seed dormancy and germination of an endangered species, Ostrya rehderiana, in Tianmu Mountain, China. J. East China Norm. Univ. Nat. Sci. 6, 150-158.
Li, D.Z., Pritchard, H.W., 2009. The science and economics of ex situ plant conservation. Trends Plant Sci. 14, 614-621.
Li, Y., Zhang, Y.L., Jiang, C.D., et al., 2010. Effect of storage temperature on spore viability and early gametophyte development of three vulnerable species of Alsophila (Cyatheaceae). Australian. J. Bot. 58, 89-96.
Li, Y., Shi, L., 2014. Effect of desiccation level and storage temperature on green spore viability of Osmunda japonica. Cryobiology 68, 446-450.
Li, Y.Y., Guan, S.M., Yang, S.Z., et al., 2012b. Genetic decline and inbreeding depression in an extremely rare tree. Conserv. Gen. 13, 343-347.
Li, Y.Y., Tsang, E.P.K., Cui, M.Y., et al., 2012a. Too early to call it a success: an evaluation of the natural regeneration of the endangered Metasequoia glyptostroboides. Biol. Cons. 150, 1-4.
Liao, Y.J., Li, X., Dong, X.H., 2010. Effect of different temperature stratifications on physiological and biochemical characteristic and seed embryos development of Taxus cuspidata Sieb.et Zucc. J. China Agric. Univ. 2010-01.
Liu, C., 2012. Effects of hot water treatment on germination and seedling growth of Gleditsia japonica. For. Sci. Technol. 2012-01.
Liu, C., Qin, S.F., Hu, X.J., 2015. Dormancy and germination of Paraisometrum mileense and their ecological implications. Plant Div. Res. 37, 278-282.
Ma, Y.P., Chen, G., Grumbine, R.E., et al., 2013. Conserving plant species with extremely small populations (PSESP) in China. Biodiv. Cons. 22, 803-809.
Mikula, A., Tomiczak, K., Makowski, D., et al., 2015. The effect of moisture content and temperature on spore aging in Osmunda regalis. Acta Physiol. Plant 37, 229-240.
Nadarajan, J., Pritchard, H.W., 2014. Biophysical characteristics of successful oilseed embryo cryoprotection and cryopreservation using vacuum infiltration vitrification, an innovation in plant cell preservation. PLoS One. http://dx.doi.org/10.1371/journal.pone.0096169e0096169.
Ouyang, Z.Q., Su, W.H., Zhang, G.F., 2006. Studies on character of seed germination of rare plant Dipteronia dyeriana. Acta Bot. Yunnanica 28, 509-514.
Park, S.Y., Hosakatte, N., Murthy, H.N., et al., 2000. In-vitro seed germination of Calanthe sieboldii, an endangered orchid species. J. Plant Biol. 43, 158-161.
Pence, V.C., 2008. Ex situ conservation of ferns and lycophytes d Approaches and techniques. Pp. 284 e 300. In: Ranker, T.A., Haufler, C.H. (Eds.), Biology and Evolution of Ferns and Lycophytes. Cambridge University Press, Cambridge, UK.
Pence, V.C., 2013a. In vitro methods and the challenge of exceptional species for Target 8 of the Global Strategy for Plant Conservation. Ann. Mo. Bot. Gard. 99, 214-220.
Pence, V.C., 2013b. In vitro methods and cryopreservation: tools for endangered exceptional species preservation and restoration. Acta Hort. 1039, 73-79. http://dx.doi.org/10.17660/ActaHortic.2014.1039.7.
Pennisi, E., 2010. Tending the global garden. Science 329, 1274-1277.
Popova, E., Sylvestre, I., Kim, H.H., et al., 2016. Frozen beauty: the cryobiotechnology of orchid diversity. Biotechnol. Adv. 34, 380-403.
Pritchard, H.W., 2004. Classification of seed storage ‘types’ for ex situ conservation in relation to temperature and moisture. In: Guerrant, E.O., Havens, K., Maunder, M. (Eds.), Ex Situ Plant Conservation e Supporting Species Survival in the Wild. Island Press, Washington DC, USA, pp. 139-161.
Pritchard, H.W., Dickie, J.B., 2003. Predicting seed longevity: use and abuse of seed viability equations. In: Smith, R.D., Dickie, J.B., Linington, S.H., et al. (Eds.), Seed Conservation e Turning Science into Practice. Royal Botanic Gardens, Kew, UK, pp. 653-722.
Pritchard, H.W., Moat, J., Ferraz, J.B.S., Marks, T.R., Camargo, J.L.C., Nadarajan, J., Ferraz, I.D.K., 2014. Innovative approaches to the preservation of tree species.For. Ecol Manag. 33, 88-98.
Pritchard, H.W., Poynter, A.C., Seaton, P.T., 1999. Interspecific variation in orchid seed longevity in relation to ultra-drying and cryopreservation. Lindleyana 14, 92-101.
Pritchard, H.W., Seaton, P.T., 1993. Orchid seed storage: historical perspective, current status, and future prospects for long-term conservation. Selbyana 14, 89-104.
Pritchard, H.W., Sacandé, M., Berjak, P., 2004. Biological aspects of tropical tree seed desiccation and storage responses. In: Sacandé, M., Jøker, D., Dulloo, M.E., et al. (Eds.), Comparative Storage Biology of Tropical Tree Seeds, pp. 319-341 (IPGRI, Danida).
Qin, Y.T., Li, X., Zhai, Z.X., et al., 2014. Research advances in biological characteristics of Taxus cuspidata seeds. North. Hortic. 2014-2023.
Quintanilla, L.G., Amigo, J., Pangua, E., et al., 2002. Effect of storage method on spore viability in five globally threatened fern species. Ann. Bot. 904, 461-467.
Rasmussen, H.N., 1996. Terrestrial Orchids e from Seed to Mycotrophic Plant.Cambridge University Press, UK.
Ren, H., Zhang, Q., Lu, H., et al., 2012. Wild plant species with extremely small populations require conservation and reintroduction in China. AMBIO 41, 913-917.
Rutherford, C., Donaldson, J., Hudson, A., et al., 2013. CITES and Cycads e a User's Guide. Royal Botanic Gardens, Kew, UK, p. 114, 1 compact disc.
Schopmeyer, C.S. (Ed.), 1974. Seeds of Woody Plants in the United States. Forest Service of the United States Department of Agriculture, Handbook Number, vol. 450, 883 pp.
Schopmeyer, C.S., Leak, W.B., 1974. Ostrya virginiana (mill.). In: Koch, K. (Ed.), Seeds of Woody Plants in the United States. Agriculture Handbook No 450. USDA, Washington DC, Forest Service, pp. 564-565.
Seaton, P., Kendon, J.P., Pritchard, H.W., et al., 2013. Orchid conservation: the next ten years. Lankesteriana 13, 93-101.
Shen, S.K., Wu, F.Q., Yang, G.S., et al., 2015. Seed germination and seedling emergence in the extremely endangered species Rhododendron protistum var.giganteum- the world's largest Rhododendron. Flora 216, 65-70.
Smith, R.D., Dickie, J.B., Linington, S.H., et al., 2003. In: Seed Conservation: Turning Science into Practice. Royal Botanic Gardens, Kew, UK, 1023 pp.
Song, X., Chen, Q., Wang, D., et al., 1984. A study on the principal storage conditions of Hopea hainanensis seeds. Sci. Silvae Sin. 20, 225-236.
Song, X., Chen, Q., Wang, D., et al., 1986. A further study on ultrastructural changes in radicle-tip cells of Hopea hainannensis during deterioration resulted from losing water. Trop. For. 4, 1-6.
Sun, W.B., 2013. Conserving Plant Species with Extremely Small Populations(PSESP) in Yunnan: Practice and Exploration. Yunnan Sci. & Technol. Press, Kunming, Yunnan, pp. 1-100.
Sun, W.B., Zhou, Z.K., Chen, W.Y., et al., 2016. Rescuing plant species with extremely small populations in China: the case of the Xichou oak (Quercus sichourensis).Int. Oaks 27, 163-170.
Suo, J., Chen, S., Zhao, Q., et al., 2015. Fern spore germination in response to environmental factors. Front. Biol. 10, 358-376.
Takakura, K., 2002. The specialist seed predator Bruchidius dorsalis (Coleoptera:Bruchidae) plays a crucial role in the seed germination of its host plant, Gleditsia japonica (Leguminosae). Func. Ecol. 16, 252-257.
Tang, R.Q., Li, X.K., Ou, Z.L., et al., 2001. The fruiting characteristics and reproductive capacity of seeds of Abies yuanbaoshanensis. Bull. Bot. Res. 3, 403-408.
Tang, W.X., Mao, S.Z., Pan, B., et al., 2009. Spatial distribution pattern of seed rain and seed germination characteristics of endangered plant Hopea chinensis.J. Fujian Coll. For. 2, 149-154.
Thammasiri, K., 2000. Cryopreservation of seeds of a Thai orchid (Doritis pulcherrima Lindl.) by vitrification. CryoLetters 21, 237-244.
Volis, S., 2016. 2016. How to conserve threatened Chinese plant species with extremely small populations? Plant Divers. 1, 53-62.
Walters, C., Berjak, P., Pammenter, N., et al., 2013. Preservation of recalcitrant seeds. Sci. 339, 915-916.
Wang, B., Ma, Y.P., Chen, G., et al., 2016a. Rescuing Magnolia sinica (Magnoliaceae), a critically endangered species endemic to Yunnan, China. Oryx 50 (3), 446-449.
Wang, C.J., Zhang, J., Wan, J.Z., et al., 2016b. The spatial distribution of threats to plant species with extremely small populations. Fron. Earth Sci. 1-10. http://dx.doi.org/10.1007/s11707-016-0550-y. April 2016.
Wang, L.F., Ou, M.W., Tan, Y.F., 2014. The study on the seed germination of endangered species Cycas debaoensis. Seed. 33, 26-29.
Wang, S.T., Zhao, Y., Wang, X.R., 2012. Study on the dormancy and accelerating germination technology for Kmeria septenrionalis Dandy seed. J. Anhui Agri. Sci. 40, 4502-4503, 4559.
Wang, X.F., Zhao, T., Yan, M., et al., 2004. Desiccation and storage of Vatica astrotricha, Hopea hainanensis, Podocarpus nagi and Acmena acuminatissma seeds. In:Sacandé, M., Jøker, D., Dulloo, M.E., et al. (Eds.), Comparative Storage Biology of Tropical Tree Seeds, pp. 165-173 (IPGRI, Danida).
Wei, R., Zhang, X.C., 2014. Rediscovery of Cystoathyrium chinense Ching (Cystopteridaceae): Phylogenetic placement of the critically endangered fern species endemic to China. J. Syst. Evol. 52, 450-457.
Wen, B., Lan, Q., He, H., 2002. Effects of illumination, temperature and soil miosture content on seed germination of Hopea hainanensis. J. Trop. Subtrop. Bot. 10, 258-262.
Wildrechner, M.P., 1990. Seed storage for the commercial propagator. Combined Proceedings Inter. Plant Prop. Soc. 40, 571-575.
Wu, C.H., Ye, X.L., Liang, C.Y., 2005. In vitro seed germination in Doritis pulcherrima.Guihaia 25, 149-152.
Xie, Z.Q., Li, Q.M., 2000. Seed characteristics of endangered plant Cathaya argyrophylla. Acta Phytoecol. Sin. 24, 82-86.
Xin, X., Jing, X.M., Sun, H.M., et al., 2004. Ecophysiological charactersitcs of seed germination of the relict plant Metasequoia glyptostroboides. Biodivers. Sci. 12, 572-577.
Yang, Q.E., Zhu, G.H., Hong, D.Y., et al., 2005. World's largest flora completed. Sci. 309, 2163.
Yu, D.P., Li, C.H., Ding, J., et al., 2011. Preliminary report on character of seed and seed culture in vitro of Parakmeria omeiensis Cheng. Res. Devel. 27, 197-199.
Yu, D.P., Peng, D.X., Li, C.H., et al., 2008. Research on the biological characters of the seeds of Acer catalpifolium Rehd. Chin. Wild Plant Resour. 6, 30-33.
Yuan, R.L., Xiang, Z.Y., Yang, W.Z., et al., 2013. Seed dormancy and germination traits of Nyssa yunnanensis. For. Res. 26, 384-388.
Zhang, M.W., Li, W.Q., Wu, Q.S., et al., 2012. The relationship between environmental factors and seed germination of Sonneratia hainanensis, an endangered species in Hainan. Pract. For. Techol. 12, 3-6.
Zhang, R.H., Shen, X.-K., Yang, F.-C., 1990. Study on growth rhythm of Ostrya rehderiana Chun. J. Zhejiang For. Coll. 1990 (1).
Zhang, R.H., Gong, G.W., Shen, X.K., et al., 1988. A study of pollen, seed and seedling of Ostrya rehderiana Chun. J. Zhejiang For. Sci. Technol 8 (4), 7-11.
Zheng, Y.L., Sun, W.B., 2009. Seed germination of Huagaimu, a critically endangered plant endemic to southeastern yunnan, China. HortTechnol. 19 (2), 427-431.
Zhou, L., Li, S.K., Deng, K.Y., et al., 2012. Aseptic sowing and tissue culture propagation of Paphiopedilum gratrixianum. J. Anhui Agri. Sci. 40, 9590-9592.

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