黑麦草幼苗对冻融和酸沉降的生理响应特征

发布时间：2018-03-19 03:08

  本文选题：黑麦草幼苗　切入点：冻融　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：冻融现象是指由于季节性或昼夜温度的变化使土壤反复出现冻结-融化的过程。冻融过程所引起的环境改变对植物生长发育产生一系列直接或间接影响,使得植物形态特征和生理功能等方面形成了特殊的适应性。酸沉降现象是指大气中的酸性物质通过降水的方式迁移到地表的过程,酸沉降胁迫对植物的生长发育产生严重不利影响,这已成为全球性环境污染问题之一。本论文以冬牧70黑麦草(Secale Cereale Lolium)为研究对象,采用模拟冻融、模拟酸沉降、模拟冻融和酸沉降复合胁迫3种胁迫试验,研究了黑麦草幼苗叶片的生理生化指标变化,揭示了黑麦草幼苗对冻融和酸沉降胁迫的生理响应特征,为进一步研究牧草和草坪草对冻融和酸沉降逆境胁迫条件下的适应性提供理论依据。主要研究结果如下:1、模拟冻融试验:随着温度变化,黑麦草幼苗叶片中渗透调节物质含量和抗氧化酶活性均呈显著性变化(P0.05)。在融-冻阶段(10~-2℃),当温度降低至-2℃时,可溶性蛋白、可溶性糖和丙二醛(MDA)含量均出现峰值;超氧化物歧化酶(SOD)、过氧化物酶(POD)活性随温度降低,呈上升趋势。在冻-融阶段(-2~10℃),当温度升高至10℃时,可溶性蛋白、可溶性糖和MDA含量均呈下降趋势;SOD、POD活性随温度降低显著升高;温度升高显著降低(P0.05)。2、模拟酸沉降试验:随着酸性增强,黑麦草幼苗叶片中可溶性蛋白、可溶性糖含量呈上升趋势;MDA含量呈下降趋势;SOD、POD活性随酸性增强,不断上升,不同处理组间存在显著性差异(P0.05)。在pH2.5酸沉降处理下,可溶性蛋白、可溶性糖含量出现最小值;MDA含量出现峰值。在pH4.5酸沉降处理下,可溶性蛋白和可溶性糖含量均出现峰值;MDA含量出现最小值。在pH2.5酸沉降处理下,SOD、POD活性均出现最小值。在pH4.5酸沉降处理下,SOD、POD活性出现峰值。3、复合胁迫试验:复合胁迫下的黑麦草幼苗叶片中可溶性蛋白含量大于单一冻融组;可溶性糖、MDA含量均小于单一冻融组。当温度降至-2℃时,可溶性蛋白、MDA含量出现峰值,当温度回升至10℃时,均出现最小值。可溶性糖含量变化规律不明显。SOD、POD活性均大于单一冻融组。当温度降至-2℃时,SOD、POD活性均出现峰值;温度回升至4℃时,SOD活性出现最小值;当温度上升至10℃时,POD活性出现最小值。冻融和酸沉降胁迫对黑麦草幼苗叶片有较敏感的反应,其生理生化指标间存在显著性差异。黑麦草幼苗具有一定的抗寒性和抗酸能力,在逆境胁迫下,黑麦草幼苗叶片可通过激活体内抗氧化酶系统及累积渗透调节物质两种途径进行适应调解,达到抑制膜脂过氧化。
[Abstract]:Freezing and thawing is the repeated freezing and thawing process of soil due to seasonal or diurnal temperature changes. The environmental changes caused by the freezing and thawing process have a series of direct or indirect effects on plant growth and development. This makes the plant form a special adaptability in terms of its morphological characteristics and physiological functions. Acid deposition is a process in which acidic substances in the atmosphere migrate to the earth's surface by precipitation. Acid deposition stress has a serious adverse effect on the growth and development of plants, which has become one of the global environmental pollution problems. The physiological and biochemical changes of the leaves of ryegrass seedlings were studied in order to reveal the physiological response of ryegrass seedlings to freeze-thaw and acid deposition stress. In order to provide theoretical basis for further study on the adaptability of forage and lawn to freezing and thawing and acid deposition stress, the main results are as follows: 1, simulated freeze-thaw experiment: with the change of temperature, The content of osmotic regulators and the activity of antioxidant enzymes in the leaves of ryegrass seedlings showed significant changes. In the thawing and freezing stage, the contents of soluble protein, soluble sugar and malondialdehyde (MDAs) were all peak when the temperature was reduced to 2 鈩，

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