中文摘要：

【目的】钾是植物生长发育所必需的营养元素之一,缺钾影响棉花的生长。钠与钾有一些相同的生理功能,钠钾替代和协同作用是提高作物钾效率有效途径之一。研究钠钾替代对不同基因型棉花钾效率的影响,旨在为生产中科学高效利用钾肥提供依据。【方法】于2013-2014年在华中农业大学利用盆栽试验,筛选并获得了钾高效高增产潜力棉花基因型103和钾低效低增产潜力棉花基因型122为试验材料,采用营养液培养对不同K^＋、Na^＋浓度处理条件下棉花苗期农艺性状（株高、根长和叶片数）、干物质积累与分配、各部位（根、茎、叶和柄）钾钠含量和钾钠积累量等进行了研究,探讨了钠钾替代作用对其钾素利用效率的影响。【结果】缺钾的条件下,施钠增加了两个基因型的根长,且103增加的幅度大于122;增加了103和122各部位干重和根冠比,而减少了根和茎的钾含量,对各部位钾积累量影响不明显,施钠还能显著提高基因型棉花103的钾利用效率,其为不施钠时的1.37倍。另外,适钾的条件下施钠,两个基因型的根长都有所增加,且103增加的幅度大于122;103和122各部位干重和总干重都显著增加,但二者根和叶钾含量显著降低,除了叶和柄其他各个部位的钾积累量都不同程度的提高;同时,103和122的钾利用效率均增加,103增加了28%,大于122的19%。此外,钾钠交互作用对根长和株高的相对生长速率,各部位干物重和根、叶中钾、钠含量和积累量以及全株钾利用效率都有显著影响。【结论】无论是否施钾、施钠均能增加两个基因型棉花的根长,通过促进根系的伸长来提高棉花对钾的吸收和生物量的积累。缺钾时施钠显著增加了103的钾效率,且适钾时施钠高效基因型103的钾效率增加幅度大于低效基因型122,表明钠钾替代和协同效应对钾高效基因型103比低效基因型122更显著。

英文摘要：

【Objectives】Potassium（ K） is one of the important nutritional elements,and is necessary for plant growth and development. While proportion of bioavailabe K in soil K pool is relatively low and it is difficult for crop to effectively use,and shortage of K resources is a problem that the world needs to solve. K deficiency can affect cotton growth but sodium（ Na） can share some physiological functions with K, so studying synergistic and substitution effects of Na and K is an effective way to improve the crop K efficiency. In this research,a solution experiment was conducted to study the substitution effects of Na and K on K use efficiency of two typical K-efficiency cotton genotypes, and to provide scientific and rational use of potash in the production process.【Methods】To study the agronomic traits（ root length,stem length and leaf numbers）,dry weights,K and Na contents,K and Na accumulation and distribution in plant organs respectively and to explore the substitution effects of Na and K on K use efficiency of two typical K- efficiency cotton genotypes,a hydroponics experiment was conducted with different K and Na treatments in Huazhong Agricultural University. 【Results】In deficient K,Na can increase the root lengths of both genotypes,and the increase amplitude in cultivar 103 is higher than in cultivar122. The dry weights of each part of 103 and 122 are increased by the Na application. The K contents in both the roots and stems of 103 and 122 are also reduced,but the difference in the K accumulation between the two cultivars is not significant. Na application significantly improves the whole plant K use efficiency of 103,which is about 1.37 times of that under the lack of sodium. In adequate K condition,Na could also increase the root lengths of both genotypes,and the dry weights of each part of both genotypes are significantly increased. Meanwhile,the K content in roots and leaves is significantly reduced,the K accumulation amounts in all the parts except for leaves and stalks are increase