四种干旱半干旱区适生灌木对几种典型重金属的耐受积累特征研究

发布时间：2018-06-13 14:19

本文选题：重金属镉 + 铅　；参考：《西南大学》2017年硕士论文

【摘要】：随着工业化进程的发展,重金属污染问题已成为全球主要的环境问题之一。我国的重金属污染问题也十分严重,并随着西部大开发战略的深入实施,重金属污染物在西部干旱半干旱地区的道路和工业园区中呈现持续累积现象,镉、铅、锌含量严重超标并影响周边环境和人类健康。当地重金属污染土壤的修复问题急需得到高度重视和切实解决。因此在污染区选择合适的植被修复物种对西部干旱半干旱地区的环境保护和污染物治理具有重要的现实意义。以四种干旱半干旱区适生灌木中华金叶榆(Ulmus pumila‘Jinye’)、水蜡(Ligustrum obtusifolium)、柽柳(Tamarix ramosissima)和银水牛果(Shepherdia argentea)两年生幼树为研究对象,通过向土壤添加外源镉(CdCl2·2.5H2O)的形式设置了CK(0 mg·kg-1)、T1(2 mg·kg-1)、T2(5 mg·kg-1)、T3(10 mg·kg-1)(以纯镉计)4个处理,研究四种干旱半干旱区灌木对镉的耐性、积累特征及生长、生理响应,以探明四种干旱半干旱区灌木是否能有效地用于宁夏乃至整个西部干旱半干旱地区表层土壤镉污染区域的植被修复;以四种干旱半干旱区灌木为研究对象,通过向土壤添加外源铅(Pb(CH3COO)2·3H2O)的形式设置了CK(0 mg·kg-1对照)、T1(2 mg·kg-1)、T2(5 mg·kg-1)、T3(10 mg·kg-1)(以纯铅计)4个处理,考察四种树种对铅的耐性、积累特性和生长生理、光合响应,以期筛选出合适的植被修复物种应用于西部干旱半干旱地区具有典型铅污染的区域;以四种干旱半干旱区灌木为研究对象,采用向土壤添加外源锌(Zn(CH3COO)2·2H2O)的形式设置了CK(0 mg·kg-1)、T1(300mg·kg-1)、T2(500 mg·kg-1)、T3(1000 mg·kg-1)4个处理组(以纯锌计),开展四种干旱半干旱区灌木对锌污染土壤的生长、光合以及耐受适应特征研究,为我国西部干旱半干旱地区耐锌树种的引进与应用提供科学依据。主要结论如下:在土壤镉含量为5.31 mg·kg-1时,中华金叶榆的株高、生物量和耐性指数(Ti)与对照组比无显著性差异。当土壤镉含量升高至10.31 mg·kg-1时,株高和生物量表现为抑制现象。随土壤镉含量的升高,水蜡、柽柳和银水牛果的株高、生物量、耐性指数和净光合速率显著下降。当土壤镉含量不超过5.31 mg·kg-1时,中华金叶榆的净光合速率并未受到限制。中华金叶榆体内的POD和CAT活性则随着土壤镉含量的增加持续增加,SOD、APX活性在镉含量为5.31 mg·kg-1时达到最大值。水蜡、柽柳和银水牛果体内的SOD、POD、CAT、APX活性均呈现了先升后降的趋势,均在土壤镉含量为5.31 mg·kg-1时达到最大值。在土壤镉含量为10.31 mg·kg-1时,中华金叶榆根部累积的最大镉含量为10.47 mg·kg-1 DW,而地上部分的转移系数较小,介于0.07~0.48。柽柳根部积累的最大镉含量为5.03 mg·kg-1 DW,地上部分的转移系数介于0.85~3.57。就水蜡和银水牛果而言,其部分镉含量表现为根茎叶,地上部分的转移系数介于0.11~0.70和0.75~0.81之间。根据本研究可以看出中华金叶榆在土壤镉含量不高于5.31 mg·kg-1时具有高的镉耐受能力和根部积累能力。柽柳在土壤镉含量为5.31 mg·kg-1时具有较好的镉耐受能力与最优的地上部分镉转移能力。因此中华金叶榆和柽柳对宁夏地区乃至整个西部干旱半干旱区土壤表层镉污染严重的地区有较强的推广应用潜力。而水蜡和银水牛果虽然在土壤镉含量为5.31 mg·kg-1时也具有较高的耐受能力,但其根部累积镉的能力和向地上部分转移的能力较差,使之相较于中华金叶榆和柽柳而言应用潜力大大降低。在铅胁迫90 d后,中华金叶榆、水蜡、柽柳的株高、生物量、净光合速率随土壤铅含量的增加呈现显著下降趋势。在土壤铅含量为431.61 mg·kg-1时,银水牛果的株高、根生物量和地上生物量与对照组比无显著性差异。中华金叶榆叶片内SOD,POD,APX在土壤铅含量为831.61 mg·kg-1时达到最大值,CAT活性在土壤铅含量为431.61 mg·kg-1时达到最大值,其中T1,T2处理组间无显著性差异且均显著高于CK,水蜡和银水牛果叶片内的SOD,POD,CAT,APX活性均呈现先升后降的趋势,在土壤铅含量为431.61 mg·kg-1时达到最大值。柽柳叶片内的SOD,POD,CAT,APX活性持续增加,均在土壤铅含量为1231.61 mg·kg-1时达到最大值。四种干旱半干旱区灌木各部分铅含量均表现为根茎叶,中华金叶榆、水蜡和银水牛果的转移系数分别介于0.14~0.2,0.06~0.16,0.40~0.72之间。而柽柳的转移系数介于0.29~0.91之间,在铅含量为1231.61 mg·kg-1时达到最大值0.91。本研究可以看出中华金叶榆在土壤铅含量为831.61 mg·kg-1时具有较好的耐受能力和根部积累铅的能力,水蜡在铅含量为431.61 mg·kg-1时也具有较好的耐受能力和积极的抗氧化能力。在土壤铅含量为431.61 mg·kg-1时,银水牛果的生长和光合均未收到限制,同时表现了较高的铅耐受能力和转移能力,使之在西部干旱半干旱区土壤表层铅污染严重的地区有较强的应用潜力。柽柳在遭受铅胁迫时,虽然限制了其生长和光合作用,但柽柳体内的抗氧化酶活性持续增加,同时具有最优的向地上部分转移铅的能力,使其对西部干旱半干旱地区表层铅污染土壤的修复具有一定的应用潜力。随土壤锌含量的增加四种干旱半干旱区灌木的株高、根生物量、地上部分生物量、叶绿素含量降低。中华金叶榆的根冠比在土壤锌含量为425和625 mg·kg-1时与对照组相比无显著性差异,1125 mg·kg-1时显著降低。当土壤锌含量超过625 mg·kg-1时,水蜡的根冠比显著低于对照。土壤锌含量超过425 mg·kg-1时,银水牛果的根冠比显著低于对照。柽柳的根冠比随土壤锌含量的增加呈上升趋势。四种干旱半干旱区灌木的净光合速率、气孔导度、胞间CO2浓度与对照组相比均显著降低,这说明在高锌胁迫下,气孔关闭导致4种植物的净光合速率下降。随土壤锌含量的增加,中华金叶榆、水蜡、柽柳和银水牛果根部、茎部和叶片中累积的锌含量都显著高于对照组,均在在1125 mg·kg-1时达到最大值,植物各部分累积的锌含量均表现为根部茎部叶片。中华金叶榆的转移系数介于0.84~1.20之间;水蜡的转移系数介于0.63~0.70之间;柽柳的转移系数介于0.82~1.31之间;银水牛果的转移系数介于0.62~1.39之间。本研究可以看出四种干旱半干旱区灌木的生长和光合随锌胁迫浓度的升高受到的抑制程度增加。高锌胁迫下水蜡生长受到限制,叶片衰老加剧,同时不具备较好的锌转移能力,使其对锌污染土壤的修复应用潜力大大降低。但中华金叶榆、柽柳和银水牛果在土壤锌含量为425 mg·kg-1和625 mg·kg-1浓度下均具有较好的锌耐受性和向地上部分迁移能力,因此中华金叶榆和柽柳作为乡土适生树种,应当在西部干旱半干旱锌污染地区大力推广。银水牛果作为外来引进树种,表现了较好的锌污染土壤修复能力,使其在西部锌污染区的研究与推广潜力大大增加。
[Abstract]:With the development of industrialization, the problem of heavy metal pollution has become one of the major environmental problems in the world. The problem of heavy metal pollution in China is also very serious. With the deep implementation of the strategy of western development, heavy metal pollutants have been accumulated in the road and industrial park of arid and semi-arid areas of Western China, cadmium, lead and zinc. In the polluted area, the selection of suitable vegetation restoration species is of great practical significance for environmental protection and pollution control in arid and semi-arid areas of Western China. Four kinds of drought and semi drought are in place. The seedlings of Ulmus pumila 'Jinye', Ligustrum obtusifolium, Tamarix (Tamarix ramosissima) and Silver Buffalo fruit (Shepherdia argentea) were studied in arid areas, and CK (2, CdCl2 2.5H2O) was set in the form of adding exogenous cadmium (CdCl2. 2.5H2O) to the soil. (1) 0 mg. Kg-1) (YISHION cadmium) (YISHION) 4 treatments, study the tolerance, accumulation, growth and physiological response of shrubs in four arid and semi-arid areas to explore whether the shrubs in four arid and semi-arid areas can be effectively used for vegetation restoration in the surface soil of the arid and semi-arid regions of Ningxia and the whole western region; four arid and semi-arid areas are arid and semi-arid. By adding CK (0 mg to kg-1), T1 (2 mg. Kg-1), T2 (5 mg kg-1) and 4 YISHION (YISHION lead), the area shrubs were added to the soil by adding exogenous lead (Pb (CH3COO) 2. 3H2O) to examine the tolerance, accumulation, physiological and photosynthetic response of four species of tree species for the selection of suitable vegetation restoration. The species was applied to the region with typical lead pollution in arid and semi-arid areas in Western China; with four arid and semi-arid shrubs as research objects, CK (0 mg. Kg-1), T1 (300mg. Kg-1), T2 (500 mg kg-1), 4 YISHION zinc (YISHION zinc), four kinds of droughts were set up in the form of adding exogenous zinc (CH3COO) 2H2O to the soil. The study on the growth, photosynthesis and tolerance adaptation of the shrubs to the zinc contaminated soil in the semi-arid area provides a scientific basis for the introduction and application of zinc tolerant tree species in arid and semi-arid areas in Western China. The main conclusions are as follows: when the soil cadmium content is 5.31 mg kg-1, the plant height, biomass and tolerance index (Ti) of the Chinese Golden Leaf elm are not significantly higher than that of the control group. The plant height and biomass were inhibited when the soil cadmium content increased to 10.31 mg. Kg-1. With the increase of soil cadmium content, the plant height, biomass, tolerance index and net photosynthetic rate of the water wax, Tamarix and Silver Buffalo decreased significantly. The net photosynthetic rate of the Chinese Golden Leaf elm was not more than 5.31 mg. Kg-1. The activity of POD and CAT in the Chinese Golden Leaf Ulmus Ulmus increased continuously with the increase of cadmium content in the soil, and the activity of SOD and APX reached the maximum when the content of cadmium was 5.31 mg. Kg-1. The activity of SOD, POD, CAT and APX in the fruit of water wax, Tamarix and Silver Buffalo showed a tendency to rise first and then descend, all of which were reached when the content of cadmium in the soil was 5.31 mg. The maximum cadmium content accumulated in the root of the Chinese Golden Leaf elm was 10.47 mg. Kg-1 DW when the soil cadmium content was 10.31 mg. Kg-1, while the transfer coefficient of the above ground part was smaller, the maximum cadmium content accumulated in the roots of Tamarix Tamarix was 5.03 mg. Kg-1 DW. The transfer coefficient of the upper part of the ground was between the 0.85~3.57. on the wax and the Silver Buffalo fruit. The partial cadmium content in the ground part is between 0.11~0.70 and 0.75~0.81. According to this study, it can be found that the cadmium tolerance and root accumulation ability of the Chinese Golden Leaf elm in the soil is not higher than 5.31 mg. Kg-1. Tamarix has a better cadmium tolerance in the soil with the content of 5.31 mg. Kg-1. Therefore, the Chinese Golden Leaf elm and Tamarix chinensis have a strong potential for spreading and applying the cadmium pollution in the soil surface of the arid and semi-arid regions of Ningxia and the whole west, while the water wax and the Silver Buffalo have high tolerance to the cadmium content of 5.31 mg. Kg-1 in the soil. The ability of accumulating cadmium in the root and the ability to transfer to the upper part of the earth is poor, so that the application potential is greatly reduced compared to the Chinese Golden Leaf elm and Tamarix. After 90 d lead stress, the plant height, biomass and net photosynthetic rate of Chinese Golden Leaf elm, wax and Tamarix are significantly decreased with the increase of soil lead content. The content of lead in soil is 431.61 m. When g / kg-1, the plant height, root biomass and aboveground biomass were not significantly different from those of the control group. The maximum value of SOD, POD and APX in the leaves of the Chinese Golden Leaf elm leaf was 831.61 mg. Kg-1, and CAT activity reached the maximum value when the lead content of soil was 431.61 mg kg-1. There was no significant difference between the T2 treatment groups and all the T2 treatment groups. Significantly higher than CK, the activity of SOD, POD, CAT and APX in the leaves of water wax and Silver Buffalo showed a tendency to rise first and then descend, and reached the maximum when the soil lead content was 431.61 mg kg-1. The SOD, POD, CAT, and APX activity in the leaves of Tamarix were increased continuously, all of which reached the maximum when the soil lead content was 1231.61 mg. Four kinds of arid and semi-arid shrubs. The partial lead content was the root and stem, the transfer coefficient of Chinese Golden Leaf elm, water wax and silver buffalo were between 0.14~0.2,0.06~0.16,0.40~0.72, and the transfer coefficient of Tamarix was between 0.29~0.91 and the maximum of 0.91. when the lead content was 1231.61 mg. Kg-1, we can see that the lead content of the Chinese Golden Leaf elm in the soil is 831.61. Mg / kg-1 had better tolerance and the ability to accumulate lead in the root. When the content of lead was 431.61 mg. Kg-1, it also had better tolerance and active antioxidant capacity. When the soil lead content was 431.61 mg. Kg-1, the growth and Photosynthesis of the silver water cattle were not limited, while the higher lead tolerance and turn were shown. In the arid and semi-arid areas of Western China, it has a strong potential for application in areas with serious lead pollution in the arid and semi-arid areas of Western China. When Tamarix is subjected to lead stress, the growth and Photosynthesis of Tamarix are limited, but the antioxidant enzyme activity in the Tamarix body continues to increase, and it has the best ability to transfer lead to the upper part of the earth, so that it is drought in the West. With the increase of soil zinc content, the plant height of four arid and semi-arid shrubs, the root biomass, the aboveground biomass and the chlorophyll content decreased with the increase of soil zinc content. The root and crown ratio of the Chinese Golden Leaf elm was not significantly worse than that of the control group when the soil zinc content was 425 and 625 mg. Kg-1. When soil zinc content exceeded 625 mg. Kg-1, the root and crown ratio of water wax was significantly lower than that of control when the content of soil zinc exceeded 625 mg. Kg-1. When soil zinc content exceeded 425 mg. Kg-1, the root crown ratio of silver water cattle was significantly lower than that of control. The net photosynthetic rate of shrubs in four arid and semi-arid areas was increased by the increase of root to crown ratio of Tamarix Tamarix with soil zinc content. The stomatal conductance and intercellular CO2 concentration were significantly lower than those of the control group, which indicated that the net photosynthetic rate of the 4 plants decreased with the stomatal closure under high zinc stress. With the increase of soil zinc content, the accumulation of zinc in the root of Chinese Golden elm, waxes, Tamarix and Silver Buffalo were significantly higher than those in the control group, both at 1125 m. When g / kg-1 reached the maximum, the zinc content accumulated in all parts of the plant was expressed in the root stem leaf. The transfer coefficient of the Chinese Golden Leaf elm was between 0.84~1.20, the transfer coefficient of water wax was between 0.63~0.70, the transfer coefficient of Tamarix was between 0.82~1.31, and the transfer coefficient of silver water cattle was between 0.62~1.39. The growth and Photosynthesis of shrubs in four arid and semi-arid areas increased with the increase of zinc stress. The growth of waxes under high zinc stress was restricted, leaf senescence increased, and no better zinc transfer ability was available, which greatly reduced the potential of zinc contaminated soil remediation. However, Chinese Golden Leaf elm, Tamarix and Silver Buffalo were greatly reduced. Under the concentration of 425 mg. Kg-1 and 625 mg. Kg-1, the fruit had better zinc tolerance and the ability to migrate to the upper part of the earth. Therefore, Chinese Golden Leaf elm and Tamarix, as native species, should be popularized in the arid and semi-arid zinc polluted areas in Western China. The ability of soil remediation has greatly increased its potential for research and popularization in zinc contaminated areas in the West.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X173

【参考文献】