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| Diaspore characteristics and ecological adaptation of Bromus tectorum L. from different distribution regions |
| YaoBin LIU1, 2, YuanMing ZHANG1*, Robert S NOWAK3, Liliya DIMEYEVA4 |
1 Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China;
2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China;
3 Department of Natural Resources and Environmental Science, University of Nevada-Reno, Reno, Nevada 89557, USA;
4 Institute of Botany and Phytointroduction, Almaty 050040, Kazakhstan |
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Abstract The invasion of nonnative plants is considered one of the main threats to the structure and function of North American ecosystems. Moreover, they can alter ecosystem processes and reduce biodiversity. In arid and semi-arid region of North America, the species of European annual grass Bromus tectorum L. is an outstanding example of these problems, which not only increase the fire density and change the fire regime, but replace native communities. Therefore, there are amount of researches on B. tectorum, including resource acquisition, water use efficiency and growth. Whereas the relevant research on the morphology of diaspore is scare. Diaspores have a fundamental role in seed germination and seedling establishment. Besides, as an important link between different generations, diaspores have a vital significance on individual reproduction and population extension. Hence, diaspores under selection for studying have an important implication. This study compares differences in seed mor-phology for Bromus tectorum collected from the United States, Kazakhstan, and Xinjiang of China. The following indices of B. tectorum diaspores were analyzed: size, thickness of covering layers, and micromorphological characteristics of the base, middle and transition area of diaspores as well as of the awn. Micromorphology of the lemma and the cross-section of the diaspore were observed by scanning electron microscopy. Results showed that thickness of the lemma and the palea of diaspores from B. tectorum-infested grasslands in the United States were reduced (P<0.05), likely because of environmental influences. This reduction facilitated the germination of diaspores and lowered the resistance of B. tectorum to adverse environmental conditions. The length of the awn also increased significantly (P<0.05), which helped in dispersal and anchoring of diaspores. Therefore, B. tectorum adapted ecologically to its new environment in the United States by strengthening its establishment ability. However, the defense capability of B. tectorum decreased. These results fit the evolution of increased competitive ability hypothesis (EICA) of invasive species. Analysis of various cells on the lemma revealed that prickle densities and col-lapsed, long epidermal cells were easily influenced by environmental factors such as temperature and moisture because of the physiologic function of these structures on silicon accumulation. However, the form and the position of silica cells, which were not greatly influenced by environmental factors, might be genetically controlled. Studying these structures at the microscopic level helps define the relationship between the diaspore and its environment. This study has a reference value for future studies on B. tectorum.
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Received: 16 November 2012
Published: 10 September 2013
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| Fund: This study was supported by the International Science and Technology Cooperation Program of China (2010DFA92720-06), with partial support to RSN from the US National Science Foundation (1047575) . |
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| Beckstead J, Meyer S E, Molder C J, et al. 2007. A race for survival: can Bromus tectorum seeds escape Pyrenophora semeniperda-caused mortality by germinating quickly? Annals of Botany, 99(5): 907−914.Bekenov A, Blank D, Grachev Y A, et al. 2001. Kazakhstan. Antelopes. Part 4: North Africa, the Middle East, and Asia. Global Survey and Regional Action Plans, 134.Black J. 1958. Competition between plants of different initial seed sizes in swards of subterranean clover (Trifolium subterraneum L.) with particular reference to leaf area and the light microclimate. Australian Journal of Agricultural Research, 9(3): 299−318.Blossey B, Notzold R. 1995. Evolution of increased competitive ability in invasive nonindigenous plants: a hypothesis. Journal of Ecology, 83(5): 887−889.Blum A. 1985. Photosynthesis and transpiration in leaves and ears of wheat and barley varieties. Journal of Experimental Botany, 36(3): 432−440.Caldwell M M, Eissenstat D M, Richards J H, et al. 1985. Competition for phosphorus: differential uptake from dual-isotope−labeled soil interspaces between shrub and grass. Science, 229(4711): 384−386.Challaiah, Burnside O C, Wicks G A, et al. 1986. Competition between winter wheat (Triticum aestivum) cultivars and downy brome (Bromus tectorum). Weed Science, 34(5): 689−693.Chambers J C, MacMahon J A. 1994. A day in the life of a seed: movements and fates of seeds and their implications for natural and managed systems. Annual Review of Ecology and Systematics, 25: 263−292. Chambers J C. 1995. Relationships between seed fates and seedling establishment in an alpine ecosystem. Ecology, 76(7): 2124−2133.Debeaujon I, Léon-Kloosterziel K M, Koornneef M. 2000. Influence of the testa on seed dormancy, germination, and longevity in Arabi-dopsis. Plant Physiology, 122(2): 403−414.Decker H F. 1964. An anatomic-systematic study of the classical tribe Festuceae (Gramineae). American Journal of Botany, 51(4): 453−463.Drake J M. 2004. Allee effects and the risk of biological invasion. Risk Analysis, 24(4): 795−802.Ellis R P. 1979. A procedure for standardizing comparative leaf anatomy in the Poaceae.Ⅱ. the epidermis as seen in surface view. Bothalia, 12: 641−671.Evans L, Rawson H M. 1970. Photosynthesis and respiration by the flag leaf and components of the ear during grain development in wheat. Australian Journal of Biological Sciences, 23(2): 245−254.Evans R A, Young J A. 1987. Seedbed microenvironment, seedling recruitment, and plant establishment on rangelands. In: Frasier G W, Evans R A. Seed and Seedbed Ecology of Rangeland Plants. Tucson: USDA-Agricultural Research Service, 212−220.Fenner M. 1980. The inhibition of germination of Bidens pilosa seeds by leaf canopy shade in some natural vegetation types. New Phytologist, 84(1): 95−101.Garnier L K M, Dajoz I. 2001. Evolutionary significance of awn length variation in a clonal grass of fire-prone savannas. Ecology, 82(6): 1720−1733.Harper J L, Lovell P, Moore K. 1970. The shapes and sizes of seeds. Annual Review of Ecology and Systematics, 1: 327−356.Hodson M, Sangster A, Parry D W. 1982. Silicon deposition in the inflorescence bristles and macrohairs of Setaria italica (L.) Beauv. Annals of Botany, 50(6): 843−850.Hull A. 1963. Competition and water requirements of cheatgrass and wheatgrasses in the greenhouse. Journal of Range Management, 16(4): 199−204.Jacobs S. 2001. The genus Lachnagrostis (Gramineae) in Australia. Telopea, 9(3): 439−448.Jiang Q, Roche D, Durham S, et al. 2006. Awn contribution to gas exchanges of barley ears. Photosynthetica, 44(4): 536−541.Kaufman P B, LaCroix J D, Rosen J J, et al. 1972. Scanning electron microscopy and electron microprobe analysis of silicification pat-terns in inflorescence bracts of Avena sativa. American Journal of Botany, 59(10): 1018−1025.Kaufman P B, Dayanandan P, Franklin C, et al. 1985. Structure and function of silica bodies in the epidermal system of grass shoots. Annals of Botany, 55(4): 487−507.Klemmedson J O, Smith J G. 1964. Cheatgrass (Bromus tectorum L.). The Botanical Review, 30(2): 226−262.Kumar D, Rangaswamy N. 1984. SEM studies on seed surface of wild and cultivated species of Vigna Savi. Indian Academy of Sciences, 93(1): 35−42.Leger E A, Espeland E K, Merrill K R, et al. 2009. Genetic variation and local adaptation at a cheatgrass (Bromus tectorum) invasion edge in western Nevada. Molecular Ecology, 18(21): 4366−4379.Leishman M R, Wright I J, Moles A T, et al. 2000. The evolutionary ecology of seed size. Seeds: the Ecology of Regeneration in Plant Communities, 2nd ed. New York: CABI Publishing, 31−57.Link S O, Keeler C W, Hill R W, et al. 2006. Bromus tectorum cover mapping and fire risk. International Journal of Wildland Fire, 15(1): 113−119.Ma J, Li J Z, Chao Z, et al. 2003. A study on microstructural feature of the seeds of desert plants in northwest China. Journal of Zhejiang Normal University: Natural Science, 26(2): 109−115.Martin A, Benayas J. 1997. Silica deposition in the inflorescence bracts and caryopsis of Gramineae of Central Spain. Primer Encuentro Europeo sobre el Estudio de Fitolitos: first European Meeting on phytolith Research. Madrid: CSIC, 146−158.Melgoza G, Nowak R S, Tausch R J. 1990. Soil water exploitation after fire: competition between Bromus tectorum (cheatgrass) and two native species. Oecologia, 83(1): 7−13.Melgoza G, Nowak R S. 1991. Competition between cheatgrass and two native species after fire: implications from observations and measurements of root distribution. Journal of Range Management, 44(1): 27−33.Meyer S E, Allen P S, Beckstead J. 1997. Seed germination regulation in Bromus tectorum (Poaceae) and its ecological significance. Oikos, 78(3): 475−485.Meyer S E, Allen P S. 1999. Ecological genetics of seed germination regulation in Bromus tectorum L. Oecologia, 120(1): 27−34.Ortúñez E, de la Fuente V. 2010. Epidermal micromorphology of the genus Festuca L. (Poaceae) in the Iberian Peninsula. Plant Systematics and Evolution, 284(3): 201−218.Parry D W, Hodson M. 1982. Silica distribution in the caryopsis and inflorescence bracts of foxtail millet [Setaria italica (L.) Beauv.] and its possible significance in carcinogenesis. Annals of Botany, 49(4): 531−540.Peart M H. 1984. The effects of morphology, orientation and position of grass diaspores on seedling survival. The Journal of Ecology, 72(2): 437−453.Pellant M. 1990. The cheatgrass-wildfire cycle–are there any solutions? General Technical Report-Intermountain Research Station, USDA Forest Service, INT-276, INT-276: 11−18.Ponzi R, Pizzolongo G. 2005. Cytological and anatomical observations on the awn and lemma of wheat (Triticum aestivum L. cv. Ofanto). Plant Biosystems-An International Journal Dealing with all Aspects of Plant Biology, 139(3): 345−348.Ray-Mukherjee J, Jones T A, Adler P B, et al. 2011. Immature seedling growth of two North American native perennial bunchgrasses and the invasive grass Bromus tectorum. Rangeland Ecology & Man-agement, 64(4): 358−365.Rice K J, Dyer A R. 2001. Seed aging, delayed germination and reduced competitive ability in Bromus tectorum. Plant Ecology, 155(2): 237−243.Sangster A, Hodson M, Parry D. 1983. Silicon deposition and ana-tomical studies in the inflorescence bracts of four Phalaris species with their possible relevance to carcinogenesis. New Phytologist, 93(1): 105−122.Shu P, Zhong W Y. 1990. A systematic and evolutionary study of Zizania L. (Gramineae) epidermal features of Pistillate lemma. Guihaia, 10(2): 107.Stewart G, Hull A. 1949. Cheatgrass (Bromus tectorum L.) −an ecologic intruder in southern Idaho. Ecology, 30(1): 58−74.Takahashi N, Isogai A, Ling P, et al. 2008. Effects of elevated atmospheric carbon dioxide concentration on silica deposition in rice (Oryza sativa L.) panicle. Plant Production Science, 11(3): 307−315.Whisenant S G. 1990. Changing fire frequencies on Idaho's Snake River Plains: ecological and management implications. General Technical Report-Intermountain Research Station, USDA Forest Service, INT-276, INT-276: 4−10.Wicks G A. 1984. Integrated systems for control and management of downy brome (Bromus tectorum) in cropland. Weed Science, 32(1): 26−31.Xie X M, Yun J F, Gao Y C, et al. 2002. Variation patterns on micro-morphological characteristics of lemmas of Agropyron Mongolicum. Bulletin of Botanical Research, 22(2): 168−174.Yang F J, Zhang Z H, Wang W J, et al. 2007. Anatomical and physio-logical diferences of eight exotic species from Asteraceae. Acta Ecologica Sinica, 27(2): 442−449.Young J A, Allen F L. 1997. Cheatgrass and range science: 1930−1950. Journal of Range Management, 50(5): 530−535. Zhang J G, Duan A G, Zhang J P, et al. 2006. A study on seed characteristics of large berry cultivars of sea buckthorn. Forest Research, 19(6): 700−705.Zhang X Q, Zhou F, Xie X M. 2010. Lemma micro-morphological characteristics of MT-1 elephant grass and its closely related varie-ties. Acta Prataculturae Sinica, 19(4):159−165.Zhou Y. 2003. Preliminary study on geographic populations of Trigonobalanus doichangensis and its effect on seed germination and seedling. Seed, 4: 3−4.Zhu Z H. 1992. Root length, leaf area and biomass of Agropyron desertorum and Bromus tectorum. Grassland and Turf, 1(1): 31−33. |
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