【作者】 孙彩霞；

【导师】 沈秀瑛；

【作者基本信息】 沈阳农业大学 ， 作物栽培学与耕作学， 2001， 博士

【摘要】 本文以抗旱性不同的玉米品种为试材，着眼于抗旱性的复杂性、系统性和整体性，分别从形态学、生理学、解剖学等角度对玉米抗旱性鉴定指标进行了系统研究。在研究结果的数量分析过程中借引了灰色系统理论及灰色关联度分析法，以及隶属函数值法、系统聚类法等科学统计分析方法，并在此基础上建立了玉米抗旱性鉴定指标体系。同时探讨了部分抗旱性鉴定指标的遗传特性。主要研究结果如下： 1.水分胁迫下，不同生长发育时期的玉米根系的生长发育受抑、生理活性下降。表现在根长、根数、根体积、根干重、根系的总吸收面积、根系的活跃吸收面积、根系的氧化力等指标在干旱情况下明显下降。对根的导管数和导管大小的研究结果表明，根系的解剖结构和抗旱性的关系密切。定义并测定了离体根系失水速率，其与抗旱性的相关性强于离体叶片失水速率。 2.水分胁迫下玉米叶片的叶形值、叶夹角、叶向值均发生了改变，但无强规律性。不同品种玉米叶片的气孔密度、叶脉多少及大小不同，这是品种间抗旱性形成差异的原因之一。 3.在渗透胁迫下玉米种子的吸水速率减小、胚根长、胚芽长、胚根干重均明显下降，因而发芽时间延迟、发芽率下降。根据PEG处理的种子萌发抗旱指数可以鉴定玉米芽期抗旱性。 4.在干旱条件下，水分在玉米各器官中的分配发生了变化，表现在根、茎、叶、鞘的含水量下降的幅度不同，其中鞘、叶含水量下降幅度大于茎、根含水量。 5.水分胁迫下玉米叶片细胞膜受到伤害，MDA含量、电解质渗出量均有增加。反应耐热性的热稳定百分率与玉米抗旱性关联密切，是一个好的抗旱性鉴定指标。 6.在干旱条件下，玉米叶片的饱和渗透势下降，同时叶片内渗透调节物质增加，其中Pro含量、ABA含量增加明显，可溶性糖含量、K⁺含量、Ca²⁺含量 有上爿口的趋势，说明玉米叶片确实具有渗透凋节能力。 7．水分胁迫下玉米叶片内的S（）D、f，（）D、CAT同工酶谱发生了变化。P（）D 同工酶谱的变化最为明显，谱带颜色深浅和条数均有变化，舰分酶分子失去了 酶活性而谱带消失，另一部分酶分子活性则明显提高或出现新的谱带。SOD、CAT 同工酶谱的变化相对不强。同时卜（）D、CAT同工酶谱在不同玉米基因型间差异 较明显，SOD则无太大差异。说明从抗旱育种角度出发，可将其作为抗旱性鉴 定的生化指标。 8．根据研究结果建立了玉米抗旱性鉴定指标体系。 9．对辽宁省生产上推广使用的丹408等近30个玉米品种的芽期、苗期、 生育中期及全生育期的抗旱性进行了鉴定。 10．遗传分析的结果表明，ROC、叶片失水速率、P，O含量、外渗电导率、 热稳定百分率、CAR含量、ASI均符合加性一显性模型。其中CAR含量、ASI、 RWC以加性效应为主，其它指标均以显性效应为主并且存在超显性。更多还原

【Abstract】 Abstract Considering the complexity of drought resistance, the morphological, physiological and anatomical characteristics of drought resistance in maize (Zea mays L.) varieties with different drought resistance were studied. The indexes systems of drought 梤esistance identification were estahl ished quantitative analyzing with methods of grey correlation degree, subordinate function values and systematic analysis of clustering. Another experiment was conducted to study the inheritance speciality of part of identification indexes of maize drought resistance. The results were as follows: 1. The growth and physiological activity of root systems were inhibited or decreased at different development stages, such as length, number, volume, dry weight, total absorbing area, active absorbing area, and oxidate ability of roots decreased evidently under water stress. The study on number and diameter of root vascular showed that the relationship between root anatomical structure and drought resistance was close. Water losing rate of uncontacted roots was defined and determined, and the relationship between it and drought resistance was closer than that of uncontacted leaves. 2. The leaf shape, leaf angle, and leaf orientation value of maize changed under water stress and the changes had not significant law. Drought resistance differed in maize cultivars partially because of differences in stomata density, size and density of vein of maize leaves; 3. Water absorbing rate of seeds, embryo-shoot length, and length and dry weight of embryo-root of maize decreased evidently, so germination was delayed and germination percentage decreased under osmotic stress. At the same time, the germination percentage of seeds was an effective index for determining drought resistance within maize germinating period. 4. Water contents in maize organs changed under water stress. The reduction of water contents was greater in leaves and vaginas than in stems and roots. 5. Cell membrane in maize leaves was injured and both of MIDA content and electrolyte leakage were increased under water stress. Percentage of thermo instability used as heat resistance had a significant correlation with the drought -12 1- resistance in different maize varieties. This trait is likely to be important in determining drought resistance. 6. The saturated osmotic potential decreased and more proline and ABA accumulated than soluble sugar, k~ and ca 2-~ This result showed that maize leaves did have the ability of osmotic adjustment. 7. The changes of bands and activities in peroxidase isozymes were more significant than others. At the same time, the differences of peroxidase and catalase isozymes in different genotypes maize were obviously than superoxide dismutase. Such results would facilitate maize breeding for improving drought resistance. 8. Establishing indexes systems of drought resistance identification of maize under water stress by the results of this study. 9. Identifying the drought resistance at germinating, seedling and other development stages, of twenty-nine maize cultivars popularly planted in Liaoning province were examined such as Dan 408. 10. Genetic analysis showed that RWC. leaves water l更多还原