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1、124852 Effects of Cd contamination on soil microbial community and physiological-biochemical indexes of Glycine max by JIANG LI A thesis submitted in partial satisfaction of the Requirements for the degree of Master of Science In environmental science and engineering in Central South University of F
2、orestry and Technology 498 Shaoshan South Road, Tianxin District Changsha Hunan 410004, P.R.CHINA Supervisor Professor LIAO Bohan April, 2008 学位论文原创性声明 本人郑重声明：所呈交的论文是本人在导师的指导下独立进行研 究所取得的研究成果。除了文中特别加以标注引用的内容外，本论文 不包含任何其他个人或集体已经发表或撰写的成果作品，也不包含为 获得中南林业科技大学或其他教育机构的学位或证书所使用过的材 料。对本文的研究作出重要贡献的个人和集体，均己在文中以
3、明确方 式表明。本人完全意识到本声明的法律后果由本人承担。 本学位论文作者完全了解学校有关保留、使用学位论文 的规定，同意学校保留并向国家有关部门或机构送交论文的 复印件或电子版，允许论文被查阅或借阅。本人授权中南林 业科技大学可以将本学位论文的全部或部分内容编入有关 数据库进行检索，可以釆用影印、缩印或扫描等复制手段保 存和汇编本学位论文。 本学位论文属于： 作者签名 ： life 74年 月屮曰 学位论文版权使用授权书 1、 保密 , f 2、 不保密 在年解密后适用本授权书。 (请您在以上相应方抿打 摘要 本论文选择黄红壤作为研究材料，采用室内培养和盆栽试验的方法，较系统地研 究了土壤重
4、金属 Cd污染与土壤环境质量生物学指标之间的关系，包括重金属 Cd污 染水平与土壤微生物生物量、土壤酶、土壤代谢熵、微生物熵等之间的关系，同时研 究了重金属Cd污染对大豆生理指标的影响以及重金属 Cd-土壤微生物 -大豆生理指标 之间的相互关系。这一研究为重金属污染土壤的修复、环境质量评价以及建立有效的 土壤重金属污染预警指标体系提供有益的参考。本论文研究所获得的主要结果如下： 1. 室内培养试验表明， Cd处理浓度较低时，土壤基础呼吸没有发生明显的变化 ; 但随着培养时间的延长以及 Cd处理浓度的提高，土壤基础呼吸逐渐增强。较低浓度 Cd离子导致土壤微生物生物量碳、氮和微生物熵的提高，高浓
5、度 Cd则会对其产生严 重的抑制作用。土壤代谢熵和碳氮比随着 Cd浓度的增加而增大。结果还显示，土壤 酸性磷酸酶和脲酶活性在相同培养时间下，随着 Cd处理浓度的增加而降低；在 Cd 处理浓度为 0-2 mg/kg时，土壤这两种酶活性随着培养时间的增长而增加，在 Cd处 理浓度为 2-20 mg/kg时，土壤酸性磷酸酶和脲酶活性随着培养时间的增加而降低。 2. 大豆盆栽试验表明，叶片脱落酸含量随着 Cd浓度的增加而增加；赤霉素含量、 过氧化物酶和脯氨酸活性在 Cd浓度较低时增大，随着 Cd浓度的增加又逐渐降低。 大豆叶片叶绿素 a、 b含量都随着 Cd浓度的增加而降低，与 Cd处理浓度呈极显著的
6、 负线性相关，其相关系数 r分别为 -0.998和 -0.996。结果还显示， Cd污染对土壤微生 物指标的影响与不同的管理方式（大豆种植情况）有关，在种植大豆的土壤中，土壤 微生物各项参数变化要小。未种植大豆土壤中的细菌、真菌和放线菌变化幅度均大于 种植大豆土壤中的微生物数量的变化。在 0-20 mg/kg镉处理浓度下，种植大豆的土 壤微生物生物量碳从 352 mg/kg下降到 333 mg/kg， 下降丙分比为 5.40%;而未种植 大豆的土壤微生物生物量碳从 320 mg/kg下降到 284 mg/kg， 下降百分比为 11.25%; 种植大豆土壤的微生物量 N由 69 mg/kg降至
7、63 mg/kg， 下降幅度为 8.70%;而未种 植的由 62 mg/kg降至 40 mg/kg， 下降幅度为35.48%。在 Cd浓度 5 mg/kg时，未种 植大豆的 Cd污染土壤中土壤基础呼吸和代谢熵增长趋势陡然提高，其基础呼吸和代 谢熵均大于种植大豆土壤，而且增加速率大于种植大豆的 Cd污染土壤。 3. 大豆生理指标与土壤微生物指标的比较表明，叶绿素、脯氨酸和赤霉素与土壤 微生物基础呼吸呈负相关；过氧化物酶活性和脱落酸则与土壤基础呼吸呈正相关；土 壤脱落酸含量与微生物生物量 N呈极显著负相关，赤霉素与微生物生物量 N呈正相 关；过氧化物酶与微生物量氮、脯氨酸与微生物生物量碳的相关系数
8、 r分别为 -0.816 和 0.746; 土壤脲酶和酸性磷酸酶酶活性则与叶绿素、脯氨酸和赤霉素呈正相关；过 氧化物酶活性和脱落酸则与土壤酶活性呈负相关。总体分析，大豆叶片叶绿素与微生 物指标相关性是最为显著的。 本课题来源于国家自然科学基金项目 （ 20677080) 关键词： Cd;黄红壤；微生物；生物量；大豆；生理指标 Abstract This research studied systematically the relationships between soil Cd pollution levels and biological indexes related to the e
9、nvironmental quality in the soils through laboratory incubation and pot experiments and by taking yellow-red soil and Glycine max as experimental materials. The fields of this research involved the relationships between soil Cd pollution levels and microbial biomass, enzymes, metabolic entropies, mi
10、crobial entropies in the Cd pollution soils, the effects of Cd pollution in soil on the physiological-biochemical indexes in Glycine max leaves, and the interactions among soil Cd pollution levels, soil microbial community, and physiological-biochemical indexes in G/jdne /mw. The purposes of this re
11、search were to offer helpfiil data for soil remedy of heavy metal pollution, for evaluation of soil environmental quality, and for establishment of forecast systems of heavy metal pollution in soils. The main results from this research are given as follows. 1. The laboratory incubation experiment of
12、 microbes in Cd-polluted soils showed that no obvious changes were observed for soil base respiration when Cd concentrations were relatively low for the soil treatment, but soil base respiration increased gradually with prolonging in incubation time and with increasing in Cd concentrations. Microbia
13、l biomass carbon and nitrogen and microbial entropy in the Cd-polluted soils increased with the treatments of lower Cd concentrations and seriously decreased with the treatments of higher Cd concentrations. Metabolic entropy and the ratios of biomass carbon to nitrogen increased generally with incre
14、asing in Cd concentrations. The results also indicated that activities of acid phosphatase and urease in soils decreased with increasing in Cd concentrations treated with a same incubation time. However, with increasing in incubation time, activities of these two soil enzymes increased when Cd conce
15、ntrations were in a range of 0-2 mg/kg, and decreased when Cd concentrations were in a range of 2-20 mg/kg. 2. The pot experiment of (7/yc/?e wax planting in Cd-polluted soils showed that contents of abscisic acid (ABA) in Glycine max leaves increased with increasing in Cd concentrations. Contents o
16、f gibbrellins (GA3) , activities of peroxidase (POD) and proline (MDA) , however, increased when the soils were treated with lower Cd concentrations and decreased when the soils treated with higher Cd concentrations. Contents of chlorophyll a or b in Glycine max leaves reduced with increasing Cd con
17、centrations, and a extremely negative linear relation was observed for contents of chlorophyll a or b in Glycine max leaves and Cd concentrations in soils (r=-0.998*, or r =-0.996* ) . From the experiment, effects of Cd pollution on microbial indexes in soils depended on the patterns of soil managem
18、ent. For example, the change scopes of amounts of bacteria, epiphytes, and actinomycetes were lower in the Glycine max planted soils than those in the unplanted soils. In the range of Cd concentration from 0 up to 20 mg/kg, microbial biomass carbon decreased from 352 to 333 mg/kg in the planted soil
19、s (a decrease of 5.40%) and from 320 to 284 mg/kg in the unplanted soils (a decrease of 11.25%) ; meanwhile, microbial biomass nitrogen decreased from 69 to 63 mg/kg in the planted soils (a decrease of 8.70%) and from 62 to 40 mg/kg in the unplanted soils (a decrease of 35.48%) . When Cd concentrati
20、on higher than 5 mg/kg, soil base respiration and metabolic entropy enhanced suddenly in the unplanted soils, and those two indexes were much higher than those in the planted soils. 3. A comparison of physiological-biochemical indexes in Glycine max leaves and soil microbial indexes indicated that c
21、ontents of chlorophyll, MDA, and GA3 in Glycine max leaves were negatively related to soil base respiration, and activities of POD and ABA positively related to soil base respiration. Microbial biomass nitrogen was extremely negatively related to ABA content, but positively related to GA3 in Glycine
22、 max leaves. The correlation coefficient of POD activities in Glycine max leaves and biomass nitrogen in soils was -0.816, and that of MDA in Glycine max leaves and biomass carbon in soils was 0.746. The positive relations were also observed between activities of acid phosphatase or urease in soils
23、and contents of chlorophyll, MDA, or GA3 in Glycine max leaves; while the negative relations were observed between activities of acid phosphatase or urease in soils and activities of POD or ABA in Glycine max leaves. Generally, the relativities of chlorophyll contents and soil microbial indexes were
24、 the most remarkable among all of these relations. The subject comes from State Natural Sciences Foundation (20677080). Keywords: cadmium (Cd) ; yellow-red soil; microbe; biomass; Glycine max; physiological-biochemical indexes 目录 m w . I Abstract . Ill 1猶 . 1 1.1镉的物化性质及其危害 . 1 1.2我關污染土壤现状 . I 1.3 3
25、1.4国内外研究现状 . 3 1.4.1重金属污染对土壤微生物影响的研究进展 . 3 1.4.2重金属污染对土壤微生物生物量影响的研究进展 . 4 1.4.3重金属污染对土壤微生物生物活性影响的研究进展 . 5 1.4.4 土壤环境因子对微生物的影响 . 8 1.4.5重金属污染对土壤微生物群落 结构影响 . 9 1,5全文研究目的意义 . 11 1.5.1研究依据 . 11 1.5.2研究 g的 . 11 1.53 11 2材料和方法 .12 2.1供试材料 . 12 2.2 mZMi. . 12 2.2.丨土壤基本理化性质分析 . 12 2.2.2 土壤微生物生物量的测定 . 12 2.2.3 土壤微生物活性的测定 . 13 2.2.4大豆幼苗时期生理指标测定 . 13 3镉污染对土壤微生物及其活性的影响 .14 3.1 14