钼硒单施与配施对铅胁迫下小白菜生长及生理特性的影响

摘要

重金属作为土壤污染的主要污染因子，严重影响到生态安全和人体健康。利用植物营养元素与重金属离子间的拮抗作用修复重金属污染土壤，成为重金属污染治理的一项重要技术手段。硒和钼是已被证实的重金属拮抗离子。本文通过盆栽试验研究了钼硒配施对不同铅污染水平(0、5、50 mg·kg)上小白菜铅毒害的缓解作用。通过分析小白菜鲜重和干重、不同部位微量元素含量、抗氧化指标以及土壤相关元素含量的变化，初步探讨了钼硒缓解铅毒害的生理机制。主要研究结论如下:
　　 1.低浓度的铅(5 mg·kg)对小白菜的生长代谢视乎没有太大的影响，但是施用高浓度铅（50mg·kg）显著地抑制了小白菜的生长，降低了小白菜地上地下部的生物量。高浓度铅胁迫下，硒钼单施及配施均显著缓解了铅的毒害作用。施硒对正常生长条件下的小白菜产量有着显著地降低作用，但是施硒能显著地增加5 mg kg-1及50 mgkg-1两个铅水平上小白菜的产量。施钼增加了正常生长条件下小白菜的产量，但是却降低了50 mg kg铅水平上小白菜的产量。钼硒配施的处理显著地增加了所有铅水平上小白菜的产量，甚至在50 mg kg铅水平上小白菜的产量也达到了显著性水平。
　　 2.随着土壤铅水平的提高，小白菜地上部及地下部铅含量均得到了显著增加。在施铅的处理上，施硒显著地降低了小白菜铅的含量，但是施钼显著地增加了施铅处理上小白菜铅的含量;钼硒交互对降低50 mg kg铅水平上小白菜铅含量有着显著的交互效应;在正常生长条件下的小白菜体其体内累积的铅较少。
　　 3.在铅胁迫环境下，钼硒配施二者之间有着显著地交互作用。小白菜体内钼的含量随着铅水平的提高有呈现出显著地降低，同时施钼也显著的增加了小白菜体内硒的含量。在施铅处理上，钼硒配施对小白菜硒含量均有着交互效应。钼对硒有着协同作用，因为施钼促进了硒的吸收。
　　 4.与不施铅的处理相比，土壤添加50 mg kg的铅降低了小白菜地上部镁的含量;小白菜地上部钙的含量则随着铅水平的增加而增加;小白菜地上部铁的含量受施铅水平的影响较小;施硒显著地增加了50 mg kg铅水平上小白菜根锌的含量;硒能促进小白菜体内铜的累积;铅降低了小白菜锰的含量。硒能增加铅胁迫下小白菜对微量元素的吸收。
　　 5.土壤添加5 mg kg和50 mg kg铅使得小白菜超氧化物歧化酶活性得到了增强，但是活性最高的仍是不加铅的处理，活性最高的是单施钼的处理，其次是单施硒的处理，再次是钼硒配施的处理，而CK的活性最低;铅也提高了过氧化氢酶的活性，在50 mg kg铅水平上钼硒配施显著的提高了小白菜叶片过氧化氢酶的活性;铅显著地降低了小白菜过氧化物酶的活性;随着施铅水平的提高，小白菜抗坏血酸含量也得到了增加，抗坏血酸含量最大值出现在施用50 mgkg铅且施硒的处理，在不施铅的情况下施钼对小白菜抗坏血酸含量没有太大的影响，而在不施铅的情况下单独施硒以及钼硒配施对小白菜抗坏血酸含量有显著提高作用。施铅提高了小白菜还原性谷胱甘肽的含量，以5 mg kg和50 mg kg两个铅水平上还原性谷胱甘肽含量较高，在施用50 mg kg铅且施硒的处理上达到了最大值。硒能提高所有铅水平上小白菜的抗氧化酶活性。

目录

声明

摘要

Abstract

Abbreviations

CHAPTER 1

1．Introduction

1．1 Selenium

1．2 Molybdenum

1．3 Brassica campestris L．ssp．Pekinensis

1．4 Literature review

2．Background and objectives of the research

2．1 Research main objectives

2．2 Specific Objectives

2．3 Research structure pathway

The effects of Se and Mo on the growth of Brassica campestris L．ssp．pekinensis under Pb stress

2．1 Introduction

2．2 Materials and methods

2．2．1 Soil used in this study

2．2．2 Plant Material and growth condition

2．2．3 Experiment Treatments

2．2．4 Plant biomass

2．2．5 Statistical Analysis

2．3 Results

2．3．1 Morphology

2．3．2 Biomass

3．3．3 Discussions

CHAPTER 3 Effect of Se and Mo on the content of Pb in Brassica campestris L．ssp．Pekinensis tissues under Pb stress

3．1 Introduction

3．2 Materials and Methods

3．2．1 Derermination of Pb Content in shoots and roots

3．2．2 Pb assay in the soil

3．2．3 Statistical Analysis

3．3 Results

3．3．1 Pb content in the shoots and roots of Brassica campestris L．ssp．pekinensis

3．3．2 Pb concentration in the soil

3．4 Discussion

3．3．1 Pb content in the shoots and roots of Brassica campestris L．ssp．Pekinensis

3．3．2 Pb concentranon in the soil

CHAPTER 4 Antagonistic interaction between Se and Mo under the influence of Pb stress in Brassica campestris L．ssp．Pekinensis

4．1 Introduction

4．2 Materials and Methods

4．2．1 Soil

4．2．2 Assay of Se content in the shoots and roots

4．2．3 Analysis of Mo content in the leafs and roots of

4．2．4 Assay of Se concentration in the soil after experiment

4．2．5 Assay of Mo concentration in the soil after experiment

4．3 Statistical Analysis

4．4 Resulis

4．4．1 Se content in the shoots and roots of Brassica campestris L．ssp．Pekinensis

4．4．2 Mo contents in the shoots and roots of Brassica campestris L．ssp．Pekinensis

4．4．3 Se concentration in the soil after the experiment

4．4．4 Mo concentration in the soil after the experiment

4．5 Discussion

4．5．1 Se content in the shoots and roots of Brassica campestris L．ssp．Pekinensis

4．5．2 Mo contents in the shoots and roots of Brassica campestris L．ssp．Pekinensis

4．5．3 Se concemration in the soil after the experiment

4．5．4 Mo concentration in the soil after the experiment

CHAPTER 5 Effect of Se and Mo on the minerals elements uptake by Brassica campestris L．ssp．Pekinensis under Pb stress

5．1 Introduction

5．2 Materials and methods

5．2．1 Derermination micro-elements in shoots and roots

5．2．2 Statistical Analysis

5．3 Results

5．3．1 Macro and micro-elements content in shoots and roots of Brassica campestris L．ssp．Pekinensis under Pb stress

5．4 Discussion

CHAPTER 6 Reaction of antioxidant enzymes activities on Se and Mo in attempt to alleviate Pb toxicity

6．1 Introduction

6．2 Materials and MenIods

6．2．1 Soil utilized in this study

6．2．2 Plant materials

6．2．3 Analysis of antioxidant enzymes activities：SOD，CAT and POD

6．2．4 Analysis of antioxidant non-enzymes activities：AsA and GSH

6．2．5 Statistical Analysis

6．3 Results

6．3．1 Analysis of antioxidant enzymes activities(SOD EC1．15．1．1)in shoots of Brassica campestris L．ssp．pekinensis

6．3．2 CAT EC 1．11．1．6 enzymes activity in the shoots of Brassica campestris L．ssp．pekinensis

6．3．3 POD EC 1．11．1．7 Enzymes activity in the shoots of Brassica campestris L．ssp．pekinensis

6．4 Non-enzymes antioxidants contents in the shoots of Brassica campestris L．ssp．pekinensis

6．4．1 AsA contents

6．4．2 GSH contents

6．5 Discussion

CHAPTER 7

7．1 conclusion

References

Acknowledgements