干旱胁迫对不同抗旱类型芜菁苗期生理特性的影响

Effects of drought stress on physiological traits ofdifferent drought-resistant turnip seedlings

以干旱敏感型芜菁(WJC106)和抗旱型芜菁(WJC129)为试验材料,采用盆栽自然干旱方法,研究干旱胁迫对不同抗旱类型芜菁苗期丙二醛含量、相对电导率、抗氧化酶活性、渗透调节物质、光合荧光以及叶片气孔形态特征的影响。结果表明:干旱胁迫显著增加芜菁苗期丙二醛含量和相对电导率,WJC106的增幅分别为59.71%和27.05%,WJC129分别为54.52%和20.06%,其细胞膜受损程度较大。WJC129有较强的调节能力,在干旱胁迫下其抗氧化酶活性和渗透调节物质的含量显著高于WJC106。干旱胁迫下WJC106和WJC129脯氨酸增幅分别为85.22%和88.97%,可溶性蛋白增幅分别为32.51%和58.26%,脯氨酸和可溶性蛋白起主要渗透调节作用。干旱胁迫除对芜菁有效光量子产量影响不明显之外,对叶绿素含量、光合及荧光参数均造成负面影响,其中WJC106受影响较大,WUE下降了71.5%,而WJC129光合及荧光各项指标相对比较稳定,WUE反而增加了18.2%。干旱胁迫使两个不同抗旱类型的芜菁苗期叶片气孔变小,保卫细胞变薄,气孔开度和气孔张开率显著减小。在干旱胁迫下,抗旱型芜菁的气孔开度、气孔张开率和气孔保卫细胞厚度著大于干旱敏感型,仍能维持较高的光合作用。WJC129抗旱型芜菁叶片表面有蜡质层覆盖,使其抗旱性增加。

Drought sensitive variety(WJC106)and drought resistant variety(WJC129)were used as experimental materials in this study to examine the physiological response of different drought resistant types of turnips to drought stress at seedling stage.The effects of drought stress on malondialdehyde,relative conductivity,antioxidant enzyme activity,osmoregulation substances,photosynthetic fluorescence and leaf stomatal morphological characteristics were examined.The results showed that drought stress significantly increased the MDA content and relative conductivity of turnip seedlings.Drought-sensitive increases were 59.71%and 27.05%.The drought-resistant types were 54.52%and 20.06%,and their cell membranes were damaged to a large extent.And drought resistant varieties had strong regulation ability.Under drought stress,the activity of antioxidant enzymes and the content of osmoregulation substances were significantly higher than those of drought sensitive varieties.The increases of WJC106 and WJC129 proline under drought stress were 85.22%and 88.97%and soluble protein increments were 32.51%and 58.26%.Proline and soluble protein played the main role in osmoregulation.Drought stress had a negative impact on chlorophyll content,photosynthesis and fluorescence parameters,except that it had no obvious impact on yield of effective light quanta of turnips.WJC106 was greatly affected,and WUE decreased by 71.5%,while WJC129 had relatively stable photosynthetic and fluorescence indicators,and WUE increased by 18.2%.Drought stress reduced leaf stomata,guard cells,stomatal opening and stomatal opening rate of two different drought resistant types of turnips at seedling stage.The stomatal characteristic value of drought resistant turnip was significantly higher than that of drought sensitive turnip while still maintaining high photosynthesis.The leaf surface of drought-resistant turnip(WJC129)was covered with a waxy layer,which increased its drought resistance.The surface of the leaf was covered with a waxy layer,which increased its drought resistance.