内源NO参与锌、铁、铜复合处理下小麦幼苗生理生化特性的变化

发布时间：2018-05-08 23:35

本文选题：小麦 + 锌铁铜复合　；参考：《西北师范大学》2015年硕士论文

【摘要】：随着工业化和城市化进程的不断深入,由工业和生活废水的排放、污水灌溉等原因造成的土壤环境污染日益严重。重金属在土壤中的滞留时间长、移动性差,并且通常以多种不同金属复合的形式共存。重金属不仅影响土壤的组成、结构和功能,造成农作物的减产,而且通过食物网迁移到不同生物体内,直接或间接地影响人和动物的健康。锌(Zn)、铁(Fe)和铜(Cu)是生物体必需的微量金属元素,参与植物体内多种生理过程,如生长发育、光合和呼吸作用、元素代谢、生物大分子合成等。然而,重金属过量时会抑制植物生长、引起代谢紊乱、活性氧失衡并驱动植物抗氧化应答。一氧化氮(NO)是广泛分布于生物体内的一种关键信号分子,在植物的生长发育和防御应激反应中发挥重要作用。本实验以西北地区广泛种植的“宁春4号”小麦为材料,研究了NO清除剂2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide(PTIO)的加入对Zn、Fe和Cu复合处理下小麦根生长及其他生理生化特性的影响,以探讨NO对Zn、Fe和Cu复合处理下小麦植物毒性的影响及其响应机制。主要研究结果如下:1.Zn、Fe和Cu复合处理明显抑制小麦幼苗根和茎的生长,且对根的抑制作用强于茎,其中Zn+Fe处理抑制作用最弱,而Zn+Fe+Cu处理抑制作用最强。PTIO的加入对Zn、Fe和Cu复合处理下小麦幼苗根和茎的生长没有显著的影响。2.与对照相比,Zn、Fe和Cu复合处理导致了小麦根中Zn、Fe、Cu和Mn含量的升高,但降低了Na、K和Ca的含量;相关处理下叶片中Zn、Fe和Mn的含量升高而Cu、Na、K和Ca的含量降低。PTIO的使用诱导了Zn、Fe和Cu复合处理的根中Fe、Mn和Ca含量进一步升高、K含量降低以及叶片中Ca含量的升高。3.Zn、Fe和Cu复合处理下小麦根尖NO荧光强度高于对照,其中Zn+Fe处理下NO荧光最亮。PTIO的加入减弱了金属复合处理下根中NO的荧光强度。4.除Zn+Fe处理外,在其他重金属复合处理下,小麦根中脯氨酸含量均显著升高,其中Zn+Cu处理下脯氨酸含量最高,PTIO的加入对金属复合处理下脯氨酸的积累无显著影响。5.Zn、Fe和Cu复合处理下小麦幼苗中总的和质外体中的过氧化氢(Hydrogen peroxide,H2O2)、超氧阴离子(Super anion,O2·ˉ)和羟自由基(Hydroxyl radical,·OH)含量均升高。PTIO的使用进一步诱导重金属复合处理下根中H2O2、O2·ˉ和·OH的积累,其中PTIO和Zn+Fe+Cu共同处理下这三项指标的含量最高。6.Zn、Fe和Cu复合处理下小麦幼苗根中抗坏血酸过氧化物酶(Ascorbate peroxidase,APX)、质外体超氧化物歧化酶(Superoxide dismutase,SOD)和质外体过氧化物酶(Peroxidase,POD)活性的升高,而谷胱甘肽还原酶(Glutathione reductase,GR)和质外体过氧化氢酶(Catalase,CAT)活性降低。PTIO的加入抑制了Zn、Fe和Cu复合处理下小麦根中总的POD、GR和质外体CAT的活性,但促进了质外体SOD和APX的活性的升高。上述结果表明:Zn、Fe和Cu复合处理对小麦的植物毒可能与Zn、Fe和Cu元素在根叶中过度积累以及活性氧自由基(ROS)的大量产生有关。重金属复合处理下脯氨酸含量的增加、NO的产生以及SOD和质外体POD、APX活性的升高在一定程度上缓解ROS诱导的氧化损伤。此外,NO清除剂PTIO的加入不影响Zn、Fe和Cu复合处理对小麦生长的抑制,但进一步诱导ROS的产生,导致总POD、GR和质外体CAT活性的降低,说明NO可能与金属复合处理下小麦幼苗中的酶促抗氧化反应的调控有关。
[Abstract]:As the process of industrialization and urbanization continues to deepen, the soil environmental pollution caused by the emission of industrial and living waste water, sewage irrigation and other causes is increasingly serious. Heavy metals are detained in the soil for long time, poor mobility, and usually coexist in various forms of metal compound. Heavy metals not only affect the composition, structure and structure of soil. Function, resulting in the reduction of crop production, and directly or indirectly affecting the health of humans and animals through the migration of food networks to different organisms. Zinc (Zn), iron (Fe) and copper (Cu) are essential trace metals in organisms, participating in a variety of physiological processes in plants, such as growth and development, photosynthesis and respiration, element metabolism, biological macromolecules. However, excessive heavy metals can inhibit plant growth, cause metabolic disorders, active oxygen imbalance and drive plant antioxidant responses. Nitric oxide (NO) is a key signal molecule widely distributed in organisms and plays an important role in plant growth and defense stress response. This experiment is widely cultivated in the northwest region. The effect of NO scavenger 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (PTIO) on the root growth and other physiological and biochemical characteristics of wheat under the compound treatment of Zn, Fe and Cu was studied. The effect of NO on the toxicity of Zn, Fe and Cu in the compound treatment of wheat under the compound treatment of Zn, Fe and Cu was studied. The results are as follows: 1.Zn, Fe and Cu compound treatment obviously inhibit the growth of root and stem of wheat seedlings, and the inhibition effect on root is stronger than that of stem. The inhibition effect of Zn+Fe treatment is the weakest, while the strongest inhibition effect of Zn+Fe+Cu treatment.PTIO on the growth of root and stem of wheat young seedlings under Zn, Fe and Cu compound treatment has no significant effect on.2. compared with control, Zn Fe and Cu compound treatment resulted in the increase of Zn, Fe, Cu and Mn content in the wheat roots, but decreased the content of Na, K and Ca; the content of Zn, Fe and Mn in the leaves increased. The fluorescence intensity of NO in root tip of wheat was higher than that of control under the combined treatment of.3.Zn, Fe and Cu. The addition of the brightest.PTIO of NO fluorescence under Zn+Fe treatment weakened the fluorescence intensity of NO in the root of the metal compound treatment and.4. except Zn+Fe treatment, and the proline content in the root of wheat increased significantly under the compound treatment of other heavy metals, which was under Zn+Cu treatment. The content of proline was the highest, and the addition of PTIO had no significant effect on the accumulation of proline in the compound treatment of.5.Zn. The hydrogen peroxide (Hydrogen peroxide, H2O2) in the total and the outer mass of wheat seedlings was treated with Fe and Cu, and the content of superoxide anion (Super anion, O2.) and hydroxyl radical (Hydroxyl radical,. The accumulation of H2O2, O2 and OH in the roots of heavy metals was further induced, in which the highest content of these three indexes was.6.Zn with PTIO and Zn+Fe+Cu, and the ascorbic acid peroxidase (Ascorbate peroxidase, APX) in the roots of Wheat Seedlings under the combined treatment of Fe and Cu, and the superoxide dismutase (Superoxide), and the extracellular superoxide dismutase (Superoxide), and in the root of the wheat seedlings were treated with Fe and Cu. The activity of Peroxidase (POD) increased, while the activity of glutathione reductase (Glutathione reductase, GR) and extracellular catalase (Catalase, CAT) reduced.PTIO to inhibit Zn, Fe and Cu, the activity of the total POD in wheat roots and the extracellular matrix, but promoted the activity of the extracellular and extracellular matrices. The above results show that the plant toxicity of Zn, Fe and Cu on wheat may be related to the excessive accumulation of Zn, Fe and Cu elements in the root leaves and a large number of reactive oxygen radicals (ROS). The increase of proline content, the production of NO, and the increase of POD and APX activity of the Zn, and the increase of POD and APX activity under the compound treatment of heavy metals are to a certain extent mitigate ROS. In addition, the addition of NO scavenger PTIO does not affect the inhibition of Zn, Fe and Cu on the growth of wheat, but further induces the production of ROS, which leads to the decrease of the CAT activity of the total POD, GR and the extracellular matrix, indicating that NO may be related to the regulation of the antioxidant activity of the wheat seedlings under the metal compound treatment.

【学位授予单位】：西北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X503.231;S512.1

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