入侵植物肿柄菊的化感作用和遗传多样性研究
其他题名Allelopathy and genetic diversity of the Tithonia diversifolia,an alien invasive plant in China
唐玲
学位类型硕士
导师孙卫邦
2009-05-21
学位授予单位中国科学院昆明植物研究所
学位授予地点昆明植物研究所
学位专业植物学
关键词肿柄菊 化感作用 细胞学特征 Issr标记 遗传多样性
摘要肿柄菊(Tithonia diversifolia(Hemsl.) A.Gray)是菊科肿柄菊属植物,原产墨西哥及中美洲地区,现已经广泛分布于亚洲、非洲和太平洋的热带和亚热带地区。目前在东南亚、南非与太平洋一些地区成为入侵草地、河岸、路边的杂草,在我国的云南、广东、广西、福建、海南、香港及台湾等地区的热带和亚热带地区。肿柄菊大量逃逸生长,并逐步向高纬度和高海拔地区扩散,已成为一种危害生物多样性和农林业生产的入侵植物。为了探讨肿柄菊的成功入侵的机理,并为制定控制策略提供依据,本文对其化感作用和遗传多样性进行了研究。 肿柄菊不同器官(嫩叶、成熟叶片、落叶、腐解叶、茎、腐解茎、不定根和花等)水提液对白菜(Brassica chinensis)与外来杂草鬼针草(Bidens pilosa)种子萌发和胚轴与胚根生长有明显的影响。不同器官的水提液对种子萌发有抑制作用,且抑制作用随水提液浓度的增加而加强;相同浓度下,叶片水提液对两种植物种子的发芽率和发芽速度的抑制作用最强。不同器官水提液对两种植物种子胚根和胚轴生长的影响复杂,低浓度的水提液对胚轴与胚根的生长有促进作用。 对分布于我国的13个肿柄菊居群(云南11个,海南和厦门各1个)细胞生物学特性的研究结果表明,13个居群均为二倍体(2n=2x=34),仅在云南河口居群中观察到部分细胞的染色数目为2n=32或68(低于5%),同时部分居群之间的核型存在一定的差异。 采用ISSR分子标记对16个肿柄菊居群(我国14个,老挝2个)的329个个体进行了遗传多样性检测。筛选出的10个ISSR引物共检测到65个位点,多态条带比率PPB=84.62%,Nei’ s基因多样性指数H = 0.3599,Shannon’ s信息指数I=0.5197。居群间的遗传分化系数为GST=0.1845,基因流Nm=2.2071。AMOVA分析结果表明,有81.59% ( P<0.001) 遗传变异存在于居群内。可见,逃逸生长的肿柄菊具有较高的遗传多样性水平,居群间的基因交流频繁。 Mantel检测表明,在我国逃逸生长的肿柄菊居群间的遗传距离和地理距离不存在显著的正相关(相关性系数r=0.1592,P=0.1490>0.05)。利用SPSS13.0软件对经度、维度、海拔、年平均温度和降雨量等5个生态因子与Nei’s基因多样性指数H之间的相关性进行Pearson分析显示,肿柄菊基因多样性随地理纬度由低到高而呈现显著正相关关系(r=0.646,P=0.007),而与其它生态因子相关性不显著。 综上所述,肿柄菊水提液表现出的较强化感作用预示,在自然条件下植物体的化感物质能通过雨水淋溶而进入土壤,从而对其它植物的种子萌发和植物体的生长产生抑制作用。在细胞水平上,肿柄菊的染色体数目恒定,核型差异不明显。在分子水平上,肿柄菊表现出高水平的遗传多样性,说明该物种对环境的适应性强,易于在新的环境条件下构建新居群。
其他摘要Tithonia diversifolia (Asteraceae), a Mexico and central American native, has being widely spred into the tropical and subtropical regions in Asia, Africa and Pacific. The species is now a harmful perenial weed invading the grassland, riparian and agricultural fields in Southeast Asia, South Africa and Pacific. In China, T. diversifolia has been already widely naturalized in the tropical and subtropical areas in Yunnan, Guangxi, Guangdong, Fujian, Hainan, Hong Kong and Taiwan province, and it also has a great trend spreading into the higher altitude and further north latitude. In fact, Tithonia diversifolia has already seriously threatened the biodiversity and agroforestry production in China. In order to further understanding its invasiveness, the allelopathy and genetic diversity of Tithonia diversifolia distributed in China have been studied. The results of effects of water extraction from different organs of T. diversifolia on seed germination, radicle and plumular axis elongation of B. chinensis and Bidens pilosa revealed, that the aqueous extract from different parts of the species could inhibit the seed germination, and the inhabitation was enforced along with the concentration increasement. At same concentration levels, the extractions from the leaves of T. diversifolia presented the highest inhabitation on seed germination rate and seed germination speed of the two species. However, the radicle and hypocotyl growth of the two plants were occasionally promoted at lower concentrations of the extractions or not significantly related with the extractions. Observations on cytologies of 13 T. diversifolia populations from China (11 from Yunnan, and other 2 from Xiamen and Hainan) indicated, that the chromosome numbers of all the populations were 2n = 34 at metaphase, except some chimera cell type 2n = 32 or 68 (less than 5%) in Hekou population of Yunnan, and the basic chromosome number was x = 17. The karyotype variation at the diploid level presented a few distinguishable cytological characters. Genetic diversity of 329 individuals from 16 T. diversifolia populations (14 from China and 2 from Laos) by using ISSR molecular markers was investigated. Ten ISSRprimers were employed and some 65 clear and reproducible DNA fragments were generated. The percentage of polymorphic loci PPB was 84.62%, Nei’s (1973) gene diversity H was 0.3599, and Shannon’s Information index I was 0.5197. The coefficient of genetic differentiation (GST) was 0.1173 and the gene flow (Nm) was 2.2071. Analysis of molecular variance(AMOVA) showed that a large proportion of genetic variation of 81.59% ( P<0.001) occurred within the populations. The higher gene flow imply that gene exchanging between the populations was rather frequent. Furthermore, there was no significant associations between genetic diversity and geographic distance among the investigated T. diversifolia populations(r =0.1592, P=0.1490>0.05). The association test between the five ecological factors (longtitude, latitude, elevation, annual average temperature, annual average pecitation) and Nei’s gene diversity H,suggested that the genetic diversity of T. diversifolia was increased towarding the further north latitude(r=0.646,P=0.007). However, there were no significant correlations between the other four ecological factors and genetic diversity. In summary, allelopathic activity of the water extraction infer that and rain-water could bring the allelopathic compounds of T. diversifolia into the soil, and thus the seed germination and seedling growth of other surrounding plants migh be inhabited. The chromosome numbers from all the investigated populations were same and the karyotype variation was limited. However, genetic diversity T. diversifola investigated by ISSR presented the extremely high level of genetic diversity, and therefore the species has a rather wide adaptability to the environment. The strong allelopathic activity and adaptability to the environment might be the factors associated with its invasiveness.
页数86
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/436
专题昆明植物所硕博研究生毕业学位论文
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唐玲. 入侵植物肿柄菊的化感作用和遗传多样性研究[D]. 昆明植物研究所. 中国科学院昆明植物研究所,2009.
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