【作者】 袁伟丁；

【导师】 朱雪梅；

【作者基本信息】 四川农业大学 ， 土壤学， 2011， 硕士

【摘要】 随着我国工业的快速发展,人口剧增以及城市化进程,土壤重金属污染日益严重。土壤重金属污染不仅抑制农作物生长发育、降低产量,而且经农作物的吸收通过食物链危害人体健康。本实验是作物生产安全性系列研究之一,以成都平原紫色土为供试土壤,以重要农作物大豆为材料,按照国家环境质量标准(GB15618-1995)(旱地pH>7.5)设计重金属锌和铬浓度,采用根袋法栽种作物—大豆。通过研究锌铬复合胁迫大豆根际土与非根际土的土壤呼吸强度、微生物数量、微生物量碳(SMBC)、微生物量氮(SMBN)、微生物量磷(SMBP)、土壤脲酶活性(URASE)、土壤过氧化氢酶活性(CAT)以及土壤蔗糖酶活性(INVERTASE),利用PCR-DGGE技术分析了供试土样的根际土壤微生物多样性,揭示了在锌铬复合胁迫下,根际土壤与非根际土壤微生物学特性,为大豆的安全生产提供一定理论依据。研究结果如下：(1)在锌铬复合胁迫条件下,大豆根际土壤呼吸强度强于非根际土壤呼吸强度。当Zn为0,100mg.kg-1时,随铬浓度的增加,表现为先升再降的趋势。当Zn为250,500 mg.kg-1时,随铬浓度的增加,表现为逐渐降低的趋势；当Cr为0,90mg.kg-1时随锌浓度的增加,都表现为先升后降低的趋势。当Cr为300,400.kg-1时,随着锌浓度的增加,表现为降低的趋势。(2)在锌铬复合胁迫条件下,大豆土壤中,细菌数量为主导地位,其次是放线菌和真菌。当Zn为0,100mg.kg-1时,随铬浓度的增加,根际土壤细菌数量表现为先升后降的趋势；当Zn为250,500 mg.kg-1时,随铬浓度的增加,根际土壤细菌数量均表现降低的趋势；当Cr为0,90mg.kg-1时随锌浓度的增加,都表现为先升后降的趋势；当Cr为300,400 mg.kg-1时,随锌浓度的增加,细菌数量表现为逐渐降低的趋势；当Zn或Cr为0mg.kg-1时,根际土壤放线菌及非根际土壤细菌数量随铬或锌浓度的增加,都表现为先升后降的趋势；当Zn为100,250,500 mg.kg-1时,则随铬浓度的增加,非根际土壤细菌数量及根际土壤放线菌数量都表现为逐渐降低的趋势；当Cr为90,300,400mg.kg-1时,则随锌浓度的增加,非根际土壤细菌数量及根际土壤放线菌数量都表现为逐渐降低的趋势。真菌数量在根际与非根际土壤呈现相同的趋势。根际土壤与非根际土壤以及非根际放线菌数量都随锌或铬浓度增加,逐渐降低。(3)当Zn为0,100 mg.kg-1,根际SMBC、SMBN,随着铬浓度增加,SMBC、SMBN先增后降,当Zn为250,500 mg.kg-1时,SMBC、SMBN随铬浓度增加,逐渐降低。当铬一定时,根际SMBC、SMBN、SMBP以及非根际SMBC、SMBN、SMBP都随锌浓度增加而降低。当锌一定时,根际SMBP随铬浓度的增加而逐渐降低。当锌为0 mg.kg-1时,非根际SMBC、SMBN随铬浓度的增加,先升后降,当Zn为250,500 mg.kg-1,非根际SMBC、SMBN随铬浓度的增加,而逐渐降低。(4)大豆根际土壤酶活性大于非根际土让酶活性。当锌一定时,根际与非根际土壤URASE随着铬浓度的增加而逐渐降低；当铬为0 mg.kg-1时,根际与非根际土壤URASE,随着锌浓度增加,先升后降,当Cr为90,300,400 mg.kg-1,随着锌浓度增加,根际与非根际土壤URASE逐渐降低。当Zn为0 mg.kg-1时,根际与非根际CAT,非根际INVERTASE随着铬浓度增加先升后降,Zn为100,250,500 mg.kg-1,根际与非根际URASE、INVERTASE随着铬浓度增加而逐渐降低。当铬一定时,非根际土壤CAT,根际与非根际INVERTASE随着锌浓度的增加而逐渐降低。Cr为0,90 mg.kg-1,根际土壤过CAT随着锌浓度的增加,先升后降；Cr为300,400 mg.kg-1,根际土壤CAT随着锌浓度的增加,逐渐降低。Zn为0,100 mg.kg-1,根际土壤INVERTASE随着铬浓度增加,先升后降低；Zn为250,500 mg.kg-1,根际土INVERTASE随着铬浓度增加,逐渐降低。(5)根际土壤呼吸商小于非根际土壤呼吸商。当Zn为0,100mg.kg-1,根际与非根际土壤呼吸商随着铬浓度增加而升高,当Zn为250 mg.kg-1时,根际土壤呼吸商随着铬浓度增加,先升后降；当Zn为500 mg.kg-1时,随着铬浓度的增加,根际土壤呼吸商逐渐降低,Zn为250,500 mg.kg-1,随着铬浓度增加,非根际土壤呼吸商逐渐下降。当铬一定,根际与非根际土壤呼吸商随锌浓度先升后降。(6)真菌种群的均匀度介于0.9494-0.9994。聚类分析发现,所有真菌样品之间的相似性在37%-68%之间,真菌的种群结构有差异。细菌的均匀度非常接近,在0.9857-0.9993之间,而多样性指数在2.6368-3.2513之间。细菌之间的相似性在21%-80%之间,细菌的种群结构有差异。更多还原

【Abstract】 With the industrial development,population explosion and acceleration of urbanization,heavy metal pollution becomes more and more severe in soil.The heavy metals contamination in soil could inhibit the crop growth and reduce the yields.The heavy metals could enter into the food chain by the crop’s absorption and eventually threat the human health.This experimeant is one of the crop safety production studies. Purple soil from Sichuan Agricultural University were chosen for pot experiment.Zinc (Zn) and chromium(Cr) were added to the soil according to the national environmental quality standard (GB15618-1995)(dry land pH>7.5).The soybean was planted by root bag method.Soil respiratory intensity,microbial quantity, SMBC, SMBN, SMBP, URASE, CAT and INVERTASE of the rhizosphere and non-rhizosphere soil and the rhizosphere soil microbial diversity by PCR-DGGE were determined.On this basis,the change of the microbiology characteristics of the soybean soil under Zn and Cr stress was studied. Based on this,under Zn and Cr compound stress,the effects and discipline on microbial characteristics in rhizosphere and non-rhizosphere soil were revealed;meanwhile,this could provide theoretical basis for soybean production safety.The results were as follows:(1)The respiration of the rhizosphere soil was stronger than that of the non-rhizosphere soil. When Zn wasO and 100mg.kg’1,with the increase of the Cr concentration,the respiration of rhizosphere and non-rhizosphere soil increased first,and then decreased.When Zn was 250 and 500 mg.kg-1, with the increase of the Cr concentration，it gradually decreased.When Cr was 0 and 90mg.kg-1, with the increase of the Zn concentration,the respiration of rhizosphere and non-rhizosphere soil increased first,and then decreased. When Cr was 300 and 400mg.kg-1 with the increase of the Zn concentration,gradually decreased.(2)The bacteria was dominant in soybean soil followed by actinomycetes and fungi.When Zn was 0,100mg.kg-1,with the increase of the Cr,rhizosphere bacteria increased first,and then decreased;when Zn was 250 and 500 mg.kg-1,with the increase of the Cr,the bacteria gradually decreased.When Cr was 0 and 90mg.kg-1,with the increase of the Zn,bacteria showed an increase first and then a decrease;when Cr was 300 and 400 mg.kg-1, with the increase of the Zn,the bacteria gradually decreased. When Zn or Cr was 0 mg.kg-1, actinomycetes in rhizosphere soil and bacteria in non-rhizosphere demonstrated an increase first and then a decrease with the increase of Cr or Zn concentrations;when Zn was 100,250 and 500 mg.kg-1,with the increase of the Cr concentration,bacteria in the non-rhizosphere soil and the actinomycetes in rhizosphere soil showed a decrease;when Cr was 90,300 and 400 mg.kg-1, with the increase of Zn concentration, bacteria in the non-rhizosphere soil and the actinomycetes in rhizosphere showed a decrease. With the increase of the Zn and Cr,fungi in rhizosphere and non-rhizosphere soil gradually decreased.And the actinomycetes in non-rhizosphere soil decreased with the increase of the Zn or Cr concentration.(3)When Zn was 0 and 100 mg.kg-1,with the increase of Cr concentration,SMBC and SMBN in rhizosphere soil increased first and then decreased;when Zn was 250 and 500 mg.kg-1,SMBC and SMBN gradually decreased with the Cr increase.When the Cr concentration is certain,SMBC,SMBN and SMBP in rhizosphere and non-rhizosphere soil gradually decreased with the Zn increase. When the Zn is certain,SMBP in the rhizosphere soil gradually decreased with the Cr increase.When Zn was 0 mg.kg-1,SMBC and SMBN in non-rhizosphere soil increased first and then decreased with the Cr increase;when Zn was 250 and 500 mg.kg-1,SMBC and SMBN in non-rhizosphere soil gradually decreased with the Cr increase.(4) Soil enzyme activities in rhizosphere soil were higher than those in the non-rhizosphere soil.When Zn was certain, URASE in rhizosphere and non-rhizosphoere soil increased first and then decreased with the Cr increase;when Cr was 0 mg.kg-1, URASE in the rhizosphere and non-rhizosphoere soil increased first and then decreased with the Zn increase;when Cr was 90,300 and 400mg.kg-1,with the Zn increase, URASE in the rhizosphere and non-rhizosphoere soil decreased.When the Zn wasO mg.kg-1,CAT in the rhizosphere and non-rhizosphoere soil and I in the non-rhizosphoere soil increased first and then decreased with the Cr increase;when Zn was 100,250 and 500 mg.kg-1, URASE and INVERTASE in rhizosphere and non-rhizosphoere soil gradually decreased with the Cr increase.When Cr was certain,CAT in the non-rhizosphoere soil, URASE and INVERTASE in rhizosphere and non-rhizosphoere soil gradually decreased with the Zn increase.When Cr was 0 and 90 mg.kg-1,CAT in the rhizosphere soil increased first and then decreased with the Zn increase;when Cr was 300 and 400 mg.kg-1,that gradually decreased with the Zn increase.When Zn was 0 and 100 mg.kg-1, INVERTASE in the rhizosphere soil increased first and then decreased with the Cr increase;when Zn was 250 and 500 mg.kg-1,that gradually decreased with the Cr increase.(5) MQ in rhizosphere soil was weaker than that in the non-rhizosphere soil.When Zn was 0 and 100 mg.kg-1,MQ in rhizosphere and non-rhizosphere soil increased with the Cr increase;when Zn was 250 mg.kg-1, MQ in the rhizosphere soil increased first and then decreased with the Cr increase;when Zn was 500 mg.kg-1,MQ in the rhizosphere soil gradually decreased with the increase of Cr;when Zn was 250 and 500 mg.kg-1,MQ in the non-rhizosphere soil gradually decreased with the increase of Cr.When Cr was certain,MQ in rhizosphere and non-rhizosphere soil first increased and then decreased with the Zn increase.(6) The evenness of the fungi species was among 0.9494-0.9994.The cluster analysis found the similarity of all the sample fungi was among 37%-68%,which meant that the difference existed in fungi species structure.The evenness of the bacteria species(0.9857-0.9993) was very close,and the H was among 2.6368-3.2513.The similarity of the bacteria was 21%-80%,which meant the difference existed in bacteria species structure.更多还原