【作者】 周晓奎；

【导师】 马丹炜；

【作者基本信息】 四川师范大学 ， 细胞生物学， 2008， 硕士

【摘要】 紫茉莉(Mirabilis jalapa L.)为紫茉莉科紫茉莉属植物,是我国的入侵植物之一。采用分子标记技术分析了紫茉莉不同花色的群体的遗传变异,采用人工控制土壤水分和温度的方法,研究了紫茉莉在干旱胁迫和温度胁迫下的生理特征,并采用生物测定法和蚕豆根尖微核技术分析了紫茉莉的化感作用。结果如下:采用简单序列重复区间扩增ISSR分子标记技术对分布于四川省成都市的紫茉莉(Mirabilis jalapa L.)3种不同花色群体进行了遗传变异分析。从100条引物筛选出5条引物进行PCR扩增,共扩增出67条清晰条带,其中62条条带具多态性。紫茉莉的等位多态性位点百分数(PPB)为92. 54%,观测等位基因数(Na)为1. 9254,有效等位基因数(Ne)为1. 2354,Nei’s的基因多样性指数(H)为0. 1562,Shannon指数(I)为0. 2633。3种花色的遗传一致度在0. 9054～0. 9620之间,遗传距离在0. 0388～0. 0994之间,其中白色与黄色的遗传距离最小(0. 0388),表现出最近的亲缘关系,黄色与紫色的遗传距离稍大(0. 0994),亲缘关系稍远;根据遗传距离进行UPMGA聚类分析得出了相似的结论。紫茉莉的遗传变异主要存在于群体内,不同花色群体间的基因流(Nm)为1. 279。在干旱胁迫和温度胁迫下,紫茉莉膜脂过氧化程度、抗氧化酶系统以及渗透调节物质(可溶性糖和可溶性蛋白)发生了不同程度的变化,表明了紫茉莉通过自身调节机制来适应多种生境,这可能是其成为入侵植物,综合分析紫茉莉对逆境的敏感性大小依次为低温、高温、干旱。紫茉莉各个器官水浸提液对小麦(Triticam Aestivum L.)、莴苣(Lactuca sactiva L.)和油菜(Brassica Campestris L.)的种子萌发和幼苗生长以及蚕豆根尖细胞的有丝分裂具有化感作用,各个器官水浸提液均对受体植物种子萌发及幼苗生长产生了不同程度的抑制作用。用蚕豆根尖微核技术研究了干旱胁迫前后紫茉莉水浸提液对蚕豆根尖细胞有丝分裂的影响。结果表明,紫茉莉水浸提液对蚕豆根尖细胞具有化感作用,这种作用具有时间效应和浓度效应,能抑制细胞有丝分裂的正常进行,并随着水浸提液浓度的升高,分裂期细胞数目下降,微核率逐渐升高,同时伴随着染色体桥、染色体断裂、染色体滞后、染色体粘连及三极分裂等异常现象,具有明显的遗传毒性。紫茉莉干旱胁迫后的化感效应大于胁迫前的化感效应。更多还原

【Abstract】 Mirabilis jalapa L. belongs to the Mirabilis genus, which is classified in the familily Nyctaginaceae. It has become a major invasive plant in China. For evaluating its invasion, we estimated the genetic variation of M. jalapa with different color flowers by using inter-simple sequence repeats(ISSR)markers, investigated Ecophysiological characteristics under various environmental stresses by using artificial control soil water and temperature, and studied allelopathy of M. jalapa by bioassay methods and micronucleus test technique of Vicia faba cells. The results were as follows.Of the 100 primers, 5 produced highly reproducible ISSR bands. These primers were carried out on 3 colonys of M. jalapa with purple, white and yellow flowers from Chengdu City, Sichuan Province. High genetic variation was revealed. 67discernable DNA fragments were with 62(92. 54 %)being polymorphic. Observed number of alleles (Na), effective number of alleles (Ne), Nei’s gene diversity (H) and Shannon’s information index (I) was 1.9254, 1.2354, 0.1562 and 0.2633, respectively. The values of genetic identity range from 0. 6330 to 0. 9080. Nei’s genetic distance in the 3 colonys was from 0. 038 to 0. 0994, which was the closest(0. 0388)between colony with white flower, and colony with yellow flower and the farthest(0. 0994) between colony with yellow flower and colony with purple flower. UPGMA cluster analysis based on Nei’s genetic distance showed similar result. The genetic variation mainly occurred in colony of M. jalapa with same color flower, and Nm of different color populations was 1. 279.Under drought and temperature stresses, change of malondialdehyde (MDA) content, antioxidant enzyme system and osmotic adjustment substances (soluble sugar and soluble protein) of M. jalap indicated that M. jalapa had various resistance mechanisms to stress. Comprehensive judgment indicated that sensitivity of this species to stress was in turn low temperature, high temperature, and drought. These results might help to devise innovative approaches to control the spread of this invasive plant.In the present study, we tested the allelopathic effects of aqueous extracts of M. jalapa on seed germination and seedling growth of Triticam Aestivum L. , Lactuca sactiva L. and Brassica Campestris L. The results showed that all aqueous extracts have allelopathy on receptor plants. The aqueous root, stem and leaf extract of M. jalapa inhibited seed germination and seedling growth in a certain extent. The aqueous extracts of M. jalapa produced genetic toxicity and inhibited mitosis of V. faba root tip cells. With the increase of concentration and action time, mitotic indexes decreased and frequencies of micronucleus increased. There were some abnormal phenomenon of root tip cells such as micronucleus, chromosome bridge, chromosome break, chromosome lag, chromosome conglutination, chromosome loop and three pole divide. After drought stress, the allelopathic effect of aqueous extracs of M. jalapa on V. faba root tip cells was stronger than that before stress.更多还原