【作者】 王西志；

【导师】 彭正萍；

【作者基本信息】 河北农业大学 ， 植物营养学， 2012， 硕士

【摘要】 目前,土壤中有效钾供应不足已严重地限制了玉米生产,为弥补我国钾肥不足和提高玉米种植效益,通过研究作物品种间钾吸收和利用效率的差异,筛选和利用钾高效玉米基因型是提高玉米产量的有效途径之一。本文采用营养液培养试验进行不同钾效率玉米品种的初步筛选后,再通过土壤盆栽的方法,设置施钾肥和不施钾肥处理,以收获时玉米植株生物量为主,并结合钾效率及钾敏感度筛选出典型钾营养高效和钾营养低效基因型玉米品种。继而,通过营养液与石英砂培养相结合的方法,深入研究了不同基因型玉米高效吸收和利用钾的机理,得到的主要结论如下:1、通过营养液培养和土壤盆栽相结合的研究方法证明,豫玉23,具有较高的钾效率且耐低钾能力强,为钾营养高效玉米品种,对低钾胁迫的耐受性较强,且自身产量潜力较高,适用于资源限制性农业发展的需要,是试验筛选的理想类型;兴农998,钾效率低且耐低钾能力差,为钾营养低效玉米品种,虽然对低钾耐受力差,但由于其增产潜力较大,因此适用于地力较好,钾肥不是限制因子的土壤上种植。2、在钾吸收机理方面,缺钾条件下,豫玉23和兴农998玉米品种的株高、总绿叶面积、根干重、地上部干重、根冠比均有不同程度的降低;地上部、根和整株钾含量也有所减少;根长增大,根表面积、根直径、根体积有所下降;根际pH,2品种表现规律不一致;吸收K~+能力和K~+亲合力增大,对低钾耐受力豫玉23增强,兴农998减弱;根系解剖结构,导管数目,木质化程度,中柱径向,中皮层细胞空腔直径均降低。不同基因型间存在显著差异。缺钾时,豫玉23生物量大于兴农998,原因是其具有较大的根长、根表面积和根体积,较小的根直径,较强的根系活力、吸K~+和K~+亲合力,耐低钾能力强,根系分泌质子较多,较大的中皮层细胞空腔,皮层通气组织较发达,较多的皮层细胞数目,细胞分裂旺盛,更有助于养分的吸收。3、在钾利用机理方面,处理10d后,与供钾比,低钾降低了豫玉23和兴农998各器官的干物质积累量、根系吸钾量、各器官钾浓度、钙吸收量,钾吸收效率和木质部运输的钾量,增加了钾利用效率和钾在韧皮部的再循环。2玉米品种被下部叶位活化出的钾主要是通过韧皮部循环至根中后,再经过木质部向上部新生叶运输的,但体内光合产物和钾向上部叶的运输是不完全同步的过程。低钾处理下的豫玉23较兴农998具有较大生物量的原因是具有较高的钾吸收速率、较高的钾利用效率和较发达的根系,木质部中有更大比例的钾被分配到上部叶和根系供其生长,具有更好的分配机制。更多还原

【Abstract】 Insufficient potassium availability has seriously limited maize production. In order to make up the lack of K and improve the planting benefit of maize, studying the difference between crop varieties about K uptake and utilization and screening maize genotype of high ability to absorb K is one of the effective ways to improve the yield of maize. In the present study, different K efficient maize varieties were collected to cultivate in hydroponic culture, then set the levels of application potassium fertilizer and not application potassium fertilizer treatment under the soil culture condition. High and low K nutrition efficient maize varieties were gained by the final biomass and combined with K efficiency and potassium sensitivity. After this, the mechanism of K high uptake and utilization efficiency in different maize varieties were studied under the conditions of nutrient solution and quartz sand. The main results were as followed:1. Results in hydroponic culture and soil potted were both proved that Yuyu 23 was the best in absorbing K and tolerancing the low-K level, it was high-K nutrition efficient maize variety. With strong tolerance to low K stress, high yield potential, and suitable for the needs of development to agricultural resources restrictive,which was the ideal type screening test. Xingnong 998, which has low K uptake efficiency and low tolerance ability under K-deficiency, was the low-K nutrition efficient maize variety. Although Xingnong 998 was weak to tolerance the K-deficiency condition, but with a high yield potential, thus was suitable to plant on the soil with high fertility and K not limiting plant growing.2.For the potassium uptake mechanism, compared with the high-K level, the height, total green leaf areas, shoot, root dry weight and ratio of root to shoot of two maize in low-K level reduced; K conversion in the root, shoot and in the whole plant decreased; root length enhanced, root surface area, diameter and radius depressed; the rhizosphere pH, 2 genotypes were different; K~+ absorption ability and K~+ affinity were increased, the tolerance ability to the K-deficiency, Yuyu 23 enhanced and Xingnong 998 reduced; root anatomic structure, the catheter number, woodiness the degree, column in radial and cortical cells in the cavity diameter all reduced. There were significant differences between the two maize varieties. When lack of K, Yuyu23 had bigger biomass, because compared with Xingnong 998, Yuyu 23 had higher root length, root surface area and root volume, smaller root diameter, stronger root activity, larger K~+ absorption ability and K~+ affinity, stronger tolerance ability to K deficiency, more proton exudation, larger cortical cells in the cavity,and the cortex ventilation organization more developed, has more cortex cell number and the cell division exuberant; these advantages more help Yuyu 23 to the absorption of nutrients.3. For the potassium utilization mechanism, during the study periods, compared with the high-K level, plant dry weight, K absorption of root, K concentration in each organ, calcium absorption, K uptake efficiency and K amount transported in the xylem under the low-K condition were significantly depressed, while the K use efficiency and K amount retranslocated from leaves to the root by phloem increased. The two maize were different leaves activated the potassium mainly through the phloem cycle to the root, and by the xylem of new leaf upward transportation, but photosynthesis product and potassium transported to the up-leaves was not synchronous. The reason why low potassium with the weight of the Yuyu 23 plants are greater than that of Xingnong 998 because in Yuyu 23 there had high K absorption rate, potassium use efficiency and more developed roots, and in the xylem a greater percentage of the potassium assigned to the upper leaf and root for its growth and better distribution mechanism.更多还原