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采用旱棚试验,对3个品种谷子进行抽穗期干旱胁迫,分析谷子生理生化及产量指标的变化,筛选影响谷子抗旱的关键因素。研究发现:干旱可引起谷子旗叶相对含水量(RWC)降低、气孔导度减小、蒸腾速率和光合效率(Pn)显著下降,使株高和穗长降低,长农35和晋谷20产量下降,但晋谷34产量与非干旱对照组无显著差异;干旱组旗叶组织中过氧化氢(H2O2)含量升高,抗坏血酸过氧化物酶(APX)活性和脯氨酸(Pro)含量增高,丙二醛(MDA)含量和相对电导率在长农35和晋谷20中显著升高,晋谷34中与对照组相当。相关分析表明,产量与APX活性、Pn、叶绿素相对含量及Pro和可溶性蛋白含量呈极显著正相关,与MDA含量呈极显著负相关。主成分分析表明,第一主成分的各指标(H2O2、超氧化物歧化酶、APX、过氧化氢酶、过氧化物酶、细胞间隙CO2浓度、光合速率、水分利用率、RWC、束缚水/自由水、Pro、可溶性糖和可溶性蛋白)的变化与谷子的抗旱性密切相关,可作为谷子抽穗期抗旱性品种选育和抗旱性研究的主要指标。第二主成分各指标MDA、相对电导率、株高、茎粗、穗长、蒸腾速率和气孔导度则是次要参考指标。
The drought-shed experiment was conducted to study the drought-response of three varieties of millet at heading stage. The changes of physiological, biochemical and yield indices of millet were analyzed, and the key factors affecting millet drought resistance were selected. The results showed that: drought could cause the decrease of relative water content (RWC), stomatal conductance, transpiration rate and photosynthetic efficiency (Pn) of millet flag leaf decreased significantly, the plant height and spike length decreased, the yield of Changnong 35 and Jingu 20 , But the production of Jingu 34 had no significant difference with that of the non-arid control group. The contents of hydrogen peroxide (H2O2), ascorbate peroxidase (APX) and proline (Pro) , Malondialdehyde (MDA) content and relative conductivity were significantly increased in Changnong 35 and Jingu 20, and Jingu 34 was comparable with that in control group. Correlation analysis showed that there was a significant and significant positive correlation between yield and the activities of APX, Pn, chlorophyll, Pro and soluble protein, and significantly negative correlation with the content of MDA. Principal component analysis showed that the indexes of the first principal component (H2O2, superoxide dismutase, APX, catalase, peroxidase, intercellular CO2 concentration, photosynthetic rate, water use efficiency, RWC, irreducible water / Free water, Pro, soluble sugar and soluble protein) were closely related to the drought resistance of millet, which could be used as the main index to study the selection and drought resistance of drought-resistance cultivars at the heading stage of millet. The second principal component indicators MDA, relative conductivity, plant height, stem diameter, spike length, transpiration rate and stomatal conductance were the secondary reference indexes.