【作者】 保曙琳；

【导师】 丁小余；

【作者基本信息】 南京师范大学 ， 植物学， 2004， 硕士

【摘要】 菱属（Trapa L．）植物是我国原产的水生植物，早在新石器时代的河姆渡遗址就曾掘出过菱实，距今约有7000多年的栽培历史。菱果实鲜嫩可口，茎、叶、果实还可以入药，据《本草纲目》记载，菱具有“安中补脏，养神强志，耳聪目明，轻身耐老”等功效。本文运用rDNA ITS区序列对中国菱属的不同类群进行了鉴别、并对菱属植物间的亲缘关系进行了探讨，为进一步评价菱的种质和系统进化提供DNA分子证据。以重金属镉为污染源、稀土元素铈为缓解因子，对镉胁迫下菱毒害反应以及铈的缓解作用进行了研究，试图为菱应用于水体污染治理提供依据。 通过改良总DNA提取的CTAB法及优化ITS区序列PCR扩增的反应条件，本文共测定了中国菱属11个种类的rDNA ITS区序列，并率先向GenBank递交了该序列。实验表明：乌菱、二角菱、四角菱以及南湖菱等为栽培品种，品种之间的差异很小（?）＜1.2％)；野菱、耳菱、冠菱、格菱、细果野菱等为野生类居群，与栽培类菱鉴别的碱基位点有3个，分别在17、201和606号碱基位上，各类群间的特异性鉴别位共有17处，菱ITS区序列数据库的建立对其各类群的鉴定有着重要意义。通过分析菱的ITS区序列，菱属植物可能起源于同一种野生类群，中国菱属植物的多样性均为种内差别。此外，基于叶绿体基因组的rbcL序列，菱科与干屈菜科的亲缘关系更近些，与柳叶菜科的亲缘关系则稍远。 菱是水体净化中浮水植物的优良物种，在环境污染治理中能发挥重要作用。用单稀土元素铈处理菱发现：在低浓度0-5mg／L Ce³⁺处理范围内，菱长势良好，SOD、POD保护酶活性被激起，体内抗胁迫能力比较强，而当浓度超过5mg／L后，Ce³⁺对菱的作用就类似重金属的毒害作用，菱的生长也被抑制，铈对菱的作用存在低促高抑的剂量效应。此外，用5mg／L Ce³⁺处理受镉胁迫的菱时，发现一定浓度的铈可以缓解菱的镉毒害，Ce³⁺能有效的激起体内的保护酶系统参与活性氧等自由基的清除，降低膜脂过氧化水平，减轻镉毒害对膜的损伤，使植株的抗胁迫能力增强。电镜的组化定位可以在菱叶细胞的泡状体中发现沉淀的镉颗粒，且大部分镉分布在膜内侧，少部分以游离形式存在。菱叶细胞的镉解毒过程是通过泡状体的区域化隔离作用达到的。更多还原

【Abstract】 Trapa L., whose fruit was excavated on the Hemu site early in neolite era whose cultivating history covered at least 7000 years, is one of important domestic aquatic plants. Besides it’s delicious fruit, nearly all parts of Trapa L. including stem, leaf and fruit could be used for officinal function. Recorded by "Compendium of Materia Medica". Trapa L. has its remedy function on securing innards, reposing, hearing and seeing well, lightening body and old-defended. Here, we will assess idioplasm and systematic evolution of Trapa by analyzing it’s rDNA ITS sequences and investigate it’s mechanism of anti-toxication of heavy metal by using rare earth element-cerium with the aim of offering academic foundation for fathering environmental pollution of Trapa L.ITS sequence is a good molecular marker of authenticating the different varieties in Trapa L. ITS sequences of 11 species in China were determined by modified method of CTAB for DNA extracting and PCR for ITS amplifying. And results showed: intraspecific substitution diversity varied wee among cultivars of T. acornis Nakano, T. bispinosa Boxb, T. bicornis Osbeck (less than 1.2%). Three authenticate genetic sites between wild and cultivars were located at 17 201 and 606. The origin of Trapa L. might be derived from one wild species by analyzing ITS sequences, which would be another evidence for the controversial theme for academy. The variety among Trapa L. in China is intraspecific. Compared with Onagrariceae, Trapaceae has more close genetic relationship with Lythraceae based on rbcL sequences.Trapa L. is also a fine environmental friendly sanctifier. Cerium is handled to Trapa with the following results: low concentration of Ce3+(0-5mg/L) could excite SOD and POD , which enhanced the ability against menace, and boost the growth of Trapa. When high concentration of Ce3+ was treated, the growth of Trapa L was restrained as heavy metal did. Adding 5mg/L Ce3+ could relieve the toxication of Cadmium to Trapa. The photosynthetic systems, protective enzyme systems were subsequently generated to protect membrane system and eliminate free radical like O2-, H2O2. Deposit of heavy metal was found in vacuolar bodies by means of electron microscopic histochemistry with most grains attached tightly by inner side of membrane and partially scattered in the cytoplast. It indicated that the procedure for Trapa to detoxicate Cadmium is to phagocytize the ion into the vacuolar bodies.更多还原