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棒叶落地生根胎生苗对NaCl胁迫的耐受性评价

Evaluation of the tolerance of Kalanchoe delagoensis viviparous seedlings to NaCl stress

  • 摘要: 为探究棒叶落地生根胎生苗对NaCl胁迫下的生长和生理特性的响应机制,选取棒叶落地生根顶端的不定芽为材料,采用营养钵育苗移栽,灌根浇盐法来控制土壤的盐分含量,设定了5个NaCl浓度梯度,分别为0、0.1、0.2、0.3和0.5 mol/L,探究棒叶落地生根胎生苗在不同NaCl浓度胁迫条件下的生长和生理指标变化,并用主成分分析对其进行了评估。结果表明:棒叶落地生根的胎生苗在NaCl胁迫下,其生长和生理呈现出不同程度的响应,特别是随着NaCl胁迫浓度的上升,株高和叶片含水量不断下降,棒叶数先增加后减少,而根系有所伸长,但叶宽与对照相比差异不显著;随着NaCl胁迫浓度的增加,胎生苗叶绿素、可溶性糖、丙二醛含量,SOD和POD活性不断上升,可溶性蛋白、淀粉、脯氨酸含量以及CAT、PAL和PPO活性均先升后降,可见胎生苗通过调控体内渗透调节物质的含量及抗氧化酶活性,从而增强其NaCl胁迫的耐受性。根据耐盐阈值50%的生长量为标准,NaCl浓度为0.5 mol/L时,植株仍可以存活,但大多数生长及生理指标都受到了不同程度的抑制,说明棒叶落地生根胎生苗可适应低于0.5 mol/L浓度的NaCl胁迫。株高、叶片含水量、可溶性蛋白、抗氧化酶活性等均可作为棒叶落地生根耐盐性强弱的评价指标。

     

    Abstract: In order to investigate the mechanisms reflecting the growth and physiological characteristics of Kalanchoe delagoensis viviparous seedlings under NaCl stress, we aimed to provide a scientific and theoretical basis for the stress-resistant cultivation of K. delagoensis plants. Adventitious buds at the top of K. delagoensis leaves were used as materials, using nutrient bags filled substrate cultivation and saline water irrigation for roots method to control soil salinity, and five concentration gradients were set for NaCl, which were 0, 0.1, 0.2, 0.3 and 0.5 mol/L, the changes of growth and physiological indexes of the rooted viviparous seedlings of Stick leaf drop-root were investigated under the stress conditions of different NaCl concentrations, and evaluated by the principal component analysis. The results showed that the growth and physiological performances of the rooted viviparous seedlings under NaCl stress showed different degrees of responses, especially with the increase of NaCl stress concentration, the plant height and leaf water content decreased, the number of rod leaves increased and then decreased, while the root system elongated, but the difference of the leaf width was not significant compared with that of the control (P > 0.05). With the time extension of NaCl stress, the chlorophyll, soluble sugar, malondialdehyde contents, SOD and POD activities were increasing, and soluble protein, starch and proline contents, as well as CAT, PAL and PPO activities were firstly increasing and then decreasing, which showed that the fetal seedling enhanced its NaCl stress tolerance by regulating the contents of osmoregulatory substances and antioxidant enzyme activities in vivo. Based on the growth indicator with a salt tolerance threshold of 50%, seedlings could survive at a NaCl concentration of 0.5 mol/L, but most growth and physiological indicators are inhibited, indicating that the K. delagoensis could adapt to NaCl stress below 0.5 mol/L. Principal component analysis showed that plant height, leaf water content, soluble protein, and antioxidant enzyme activity could be used as indicators for evaluating the strength of salt tolerance in K. tubiflora.

     

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