蒋奇峰,员海燕.不同基因型玉米自交系苗期根系抗旱性向水性及解剖结构研究[J].干旱地区农业研究,2016,34(5):1~8
不同基因型玉米自交系苗期根系抗旱性向水性及解剖结构研究
Study on drought resistance, hydrotropism and anatomic structure of root system of maize inbred lines with different genotypes
  
DOI:10.7606/j.issn.1000-7601.2016.05.01
中文关键词:  玉米自交系  根系  苗期  根向水性  解剖结构  抗旱性
英文关键词:maize inbred line  root system  seedling stage  root hydrotropism  anatomic structure  drought resistance
基金项目:陕西省攻关项目(2014K02-01-01)
作者单位
蒋奇峰 College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China 
员海燕 College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China 
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中文摘要:
      试验旨在研究旱胁迫下不同基因型玉米自交系苗期根系形态、生理生化、解剖结构的差异变化,为玉米自交系抗旱种质的筛选提供可借鉴的指标、方法,为玉米自交系苗期根系抗旱遗传机理研究提供依据。试验选用了14份玉米自交系,采用PEG-6000胁迫处理,测定玉米自交系苗期13个与抗旱紧密相关的根系形态与生理生化指标,并通过方差分析、关联分析及聚类分析,对各自交系的抗旱性进行综合评价,并对其中两个抗旱性差异明显的自交系,通过石蜡切片-显微镜观察根系横切面结构的差异。结果表明:干旱胁迫下,不同玉米自交系苗期的单株根干质量、单株地上部干质量、根系长度、根直径、根伸长速率、根失水率、根系还原力均呈不同程度的下降趋势,根系可溶性糖、脯氨酸均呈不同程度的上升趋势,且不同自交系的变化幅度差异较大。随着诱导物倾斜角的增大,不同自交系根系的向水性弯曲增强,不同自交系间的差异较大,高湿度梯度条件下,自交系Mo17向水性弯曲较对照增加134%,增加幅度最大,WN897向水性弯曲增加20%,增加幅度较小。利用不同抗旱指标的加权抗旱指数,综合评价不同基因型玉米自交系的抗旱性,并将14个玉米自交系种质聚类划分为强抗旱型、中抗旱型和旱敏感型、高旱敏感型4个抗旱级别。石蜡切片结果显示,抗旱性差异明显的自交系根系解剖结构差异较大,抗旱性自交系昌7-2皮层占根系直径比例较低,不抗旱自交系WN897皮层占根系直径比例大于昌7-2,且WN897的导管直径较大。结论:采用方差分析、关联分析及聚类分析等相结合的方法对不同玉米自交系苗期抗旱性进行评估,可以较好地揭示根系性状与抗旱性的关系。根系还原力、根系可溶性糖、根系长度、根向水性对干旱胁迫的反应较其他指标敏感,可作为玉米苗期的抗旱能力和抗旱自交系选育时优先考虑的鉴定指标。旱胁迫下,抗旱性差异明显的玉米自交系根系解剖特征差异显著,强抗旱型自交系苗期根系皮层厚度较小,皮层占根系直径比例较低,根系导管直径也较高旱敏感型自交系小。
英文摘要:
      To study the different changes in root morphology, physiology and biochemistry, anatomic structure of maize inbred lines with different genotypes at the seedling stage under dry stress, to provide reference index and method for screening of drought resistant maize germplasms, and also to investigate the genetic mechanism of drought resistance for inbred lines at the seedling stage, this research was carried out. 14 maize inbred lines were employed by PEG-6000 stress treatment to determine 13 indexes which are closely related to morphological and physiological and biochemistry characteristics of drought resistance for root of maize inbred lines at the seedling stage. Through the analyses of variance, correlation and cluster, a comprehensive evaluation on the drought resistance of different maize genotypes was carried out, and two obvious differences inbred lines in drought resistance were selected for further observation on the differences in root structure by paraffin section and microscope. Under drought stress, root dry mass per plant, shoot dry mass per plant, root length, root diameter, number of lateral roots, root elongation rate, root dehydration rate, and root reducing capacity of different maize inbred lines at the seedling stage showed a trend of becoming declined at varying degrees. Soluble sugar content and proline content in roots showed a trend of being increased at varying degrees, and had obvious variations in different inbred lines. With the increase of the slope angle, root hydrotropism of different inbred lines was increased, and had obvious differences between different inbred lines. Under the condition of high humidity gradient, root hydrotropism of Mo17 was increased by 134%, which was the biggest among all, and that of WN897 was increased by 20%, which was increased less. Using weighted drought index, a comprehensive evaluation of drought resistance of different genotype maize inbred lines was given and 14 inbred lines were classified into four groups including strong drought resistant, moderate drought resistant and drought sensitive, and drought highly sensitive ones. According to the results of paraffin sections, cultivars showing significant variations in drought resistance had obvious different root system structures. The ratio of root cortex width to root diameter of the drought resistant inbred line Chang 7-2 was lower than that of the non-drought resistant inbred line WN897 that also had larger root vessel diameter. Through the combination of the methods including the analysis of variance, correlation analysis and cluster analysis, an evaluation on drought resistance of different maize inbred lines at seedling stage was given, which can better reveal the relationship between root traits and drought resistance. Root reducing capacity, soluble sugar content, root length, and root hydrotropism were sensitive to drought stress than other indexes, which can serve as the prior identification indexes for drought resistant ability and breeding selection for drought resistant inbred line. Under drought stress, the differences in root anatomy between maize inbred lines were significant. In the seedling stage, the root cortex width of the strong drought resistance was small, and the ratio of root cortex width to root diameter was lower, and the root vessel diameter was higher than the drought sensitive inbred lines.
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