【作者】 陈洁；

【导师】 林栖凤；

【作者基本信息】 华南热带农业大学 ， 作物遗传育种， 2003， 硕士

【摘要】 海南大学生物技术研究所一直致力于通过花粉管通道技术将耐盐或盐生植物总DNA导入农作物进行耐盐作物选育的工作，已经首次获得了能耐海水浇灌的耐盐番茄，通过相关研究已经证明外源DNA转入了番茄。本工作受国家教育部科技研究重点项目(地方02156)和国家海洋局耐海水浇灌的作物新种质培育研究项目(20094)资助。 本研究工作分为三个部分： 第一部分，建立水稻幼苗耐盐性的定量测定。通过在较低浓度的盐胁迫下，对海香稻14个农艺性状及生理生化指标的测定，发现海香稻在一定的盐浓度下(25mmol／L NaCl)具有最佳的生长状态。对于选定的浓度梯度，该盐度下的农艺性状及生理生化指标与其两侧的相比具有显著性，此时的盐浓度为水稻幼苗的最佳生长盐度。以此作为耐盐性定量测定的依据，选取了较为典型和容易测定的7个指标，建立了定量测定水稻幼苗耐盐性的方法，并用该法对其它四种水稻进行了耐盐性的定量鉴定，四种水稻的最适盐度依次为：US茉莉香20mmol／L、316B 15mmol／L、浓香16 15mmol／L和南341-糯12.5mmol／L。 第二部分，外源脯氨酸和盐对水稻耐盐性的影响。通过在不同盐胁迫条件下施加不同浓度的脯氨酸，对其生理生化指标进行测定，结果表明，脯氨酸对水稻幼苗的生长有一定的抑制作用，但在最适生长盐度附近，两者产生互作，对水稻幼苗的根系发育有促进作用。25mmol／LNaCl与0.4g／L Pro互作时，其根长平均数分别是只含25mmol／LNaCl及0.48／L Pro的1.07和1.35倍。因此，脯氨酸对水稻耐盐性的影响决不仅是盐害情况下产生的积累或单纯是调渗物质，胁迫下植物体内增加的脯氨酸可能有其独特的作用，这有待于进一步的研究。 第三部分，体外活性氧对水稻幼苗叶绿素的影响。实验发现，与以往的研究不同的是，短时间或剂量较小的活性氧处理可以促进高体的水稻幼苗叶绿素a向叶绿素b的转化，使叶绿素含量增加，表明活性氧有可能参与了叶绿素的合成。但是长时间和较大浓度的活性氧处理对离休叶绿素有破坏作用，活性氧的“角色”转化可能是盐胁迫信号传递的方式之一。 上述工作对水稻耐盐机制的研究来说只是揭开了“冰山的一角”，还有大量艰苦的工作需要进一步深入地研究，随着科学技术的迅猛发展，植物耐盐机制的神秘面纱终将被揭开。更多还原

【Abstract】 In the Institute of Biological Science and Technology of Hainan University, the pollen tube introduction method had been used to breed salt-tolerant crops with total DNA of halophytes or salt -tolerant plants. The salt-tolerant transformed tomato was firstly obtained and planted on the seashore beach and watered directly with full seawater. It was demonstrated that the introduction of total foreign DNA was successful through correlative researches.This thesis contains three parts. In the first part, the method for quantitative analysis on salt-tolerant property of rice seedling was established. The fourteen kinds of agronomic characters and other physiological and biochemical properties of rice seedlings of variety Haixiang Nol had been measured under lower salt concentration, which Was the most vegetal suitable for their growth. Under selected salt gradient, the tested agronomic characters and physiological and biochemical properties of Haixiang No 1 had a terribly prominent differentia than that of the adjacent area of salt gradient. The salt gradient was determined as a criterion of quantitative analysis on salt-tolerant properties of rice seedling. The method was established with seven properties, which was typical and easily got. With this method, the seedlings of four other rice varieties were analyzed quantitatively.The second part was the influences of foreign proline and salt on the salt-tolerance of rice seedlings. The agronomic characters and physiological and biochemical properties of the seedlings of Haixiang Nol had been measured under different salt and proline gradient. It was found that the rice seedlings were restrained by foreign proline However, when the seedlings growing under their optimum salt concentration, rroline promoted the development of the roots through the interaction between proline and salt. Therefore, besides as an accumulated substance or osmotic responsive to salt stress, the proline should have other functions, which needed to be studied further.The last part was the influences of foreign reactive oxygen species (ROS) on vitro chlorophyll of rice seedlings. It was found that ROS promoted thetransformation from chlorophyll a to b and increased their contents, so they maybe participated in the chlorophyll synthesis. But when acted by higher concentrate and longer time, ROS spoiled chlorophyll. Perhaps, the switching role was one of the methods on the signals transferring of salt stress.These studies on the mechanism of rice saline tolerance were only a bit of ar iceberg, and there are a lot of painstaking efforts to do. With the rapid development of science and technology, the secret veiling of plant salt-tolerant mechanism would be unclosed.更多还原