【作者】 崔国贤；

【导师】 李宗道；

【作者基本信息】 湖南农业大学 ， 作物栽培学与耕作学， 1997， 博士

【摘要】 我国是一个土壤缺钾比较严重而钾肥资探比较匮乏的国家，每年花费巨额外汇进口的钾肥仍远远不能满足生产的需求，急待探索缓解我国钾肥资源短缺的新途径，其中最经济有效的途径之一就是筛选并培育钾营养高致、耐低钾基因型农作物。 苎麻是我国的特产和重要的出口创汇作物，种植历史悠久，矿质营养生态环境较为复杂，有可能形成各种矿质营养基因类型，对其钾营养特性进行系统研究，并阐明其产生差异的机制，这对钾营养高效、耐低钾苎麻基因资源的筛选与利用，进一步提高苎麻产量、品质和钾肥使用效率，具有重要的理论和实践意义。 本研究首次以16个苎麻基因型为试验材料，采用土壤微区试验、土壤盆栽试验及溶液培养和筛选试验，比较系统地研究了苎麻不同基因型地上部生物学产量及钾营养特性的差异，并从根系的形态特征、生理及吸收动力学等方面探讨了产生差异的机制。其主要研究结果为： (1)苎麻不同基因型在地上部生物学产量及钾的吸收、累积、分配、利用等方面存在非常明显的差异，且对施钾的效应也不同。在大田供钾水平较低的土壤中，不施钾处理，苎麻不同基因型的单株平均干重、干皮重、钾含量、吸钾量、钾利用效率及钾收获指数变幅分别为13.08—34.58g、1.88—6.90g、1.67％-2.371％、0.285—0.741gK、42.18-59.88g(DW)／gK、0.213-0.330，施钾处理则分别为10.40-32.41g、1.65-6.90g、1.730％-2.690％、0.253-0.729gK、37.18-57.80g(DW)／gK、0.177-0.321。 (2)对大田微区试验结果进行综合分析，初步确定V5和V14是吸钾能力较强的基因类型，而V8和V16是吸钾能力较弱的基因类型，同时V16的钾利用效率也较低，V1为钾利用效率较高的基因类型。这为进一步开展苎麻钾营养基因型差异的机理研究提供了很好的试验材料。 (3)吸钾能力强的基因型具有根量多，特别是细根多，根系总吸收面积及活跃吸收面积大，根系CEC较高，以及适宜的根冠比等特征。更多还原

【Abstract】 Potassium supply in soil is deficiency in China, and it has not plenty of K fertilizer resource. A lot of foreign exchanges have been spent for importing K fertilizer,but it still couldn’t meet the demand of agricultural production. It is imperative to explore a new way for alleviating K resource deficiency. One of the most economic and effective ways is to screen and develop new varieties of high K efficiency and tolerant to low-K.Ramie is a native crop in China, and its fiber is an important export product earning foreign exchanges. It has been planted for thoushands of years in China. Because the ecological environment of mineral nutrition of ramie is relatively complicated,it is possible to develop different mineral nutrition genotypes from it. If the characters of K nutrition and its mechanism are studied and clarified among various genotypes of ramie,it will be very favourable to screen and utilizate ramie genotypic resource of high K efficiency and tolerant to low-K,and to improve fiber output, fiber quality and the efficiency of K fertilizer application.This study has its theoretical and practical significance in the ramie production.The differences of biomass yield and K nutrition characters of ramie were studied for the first time by field microzone experiment, soil pot culture, solution culture and screening experiment. The mechanism of genotypic differences of K nutrition were also studied by investigating root morphology,physiology and K uptake kinetics. The main results are as follows:(l)The biomass of stems and leaves, absorption, accumulation, distribution and utilization of K were significantly different among various genotypes of ramie* and its utilization efficicency of K fertilizer is different too. Under low K condition of soil, the dry更多还原