| Dedication | 第1-5页 |
| Declaration | 第5-6页 |
| Certification | 第6-7页 |
| Acknowledgement | 第7-9页 |
| Abstract | 第9-11页 |
| Table of content | 第11-13页 |
| List of Tables | 第13-14页 |
| List of figures | 第14-15页 |
| 1． INTRODUCTION | 第15-18页 |
| 1．1 Research justification | 第17页 |
| 1．2 Aims and objectives | 第17-18页 |
| 2． LITERATURE REVIEW | 第18-50页 |
| 2．1 Bio-indicator/and or Bio-monitor organism concept | 第18-20页 |
| 2．2 Evolution, life history and developmental physiology of the silkworm | 第20-24页 |
| 2．3 Chromium occurrence in the environment | 第24-33页 |
| 2．4 Effects of chemicals on living organisms | 第33-44页 |
| 2．5 Effects of chemicals on mulberry silkworm （Bornbyx mori L） races | 第44-50页 |
| 3． MATERIALS AND METHODS | 第50-56页 |
| 3．1 Materials | 第50页 |
| 3．1．1 Laboratory set up | 第50页 |
| 3．1．2 Chemicals and reagents | 第50页 |
| 3．1．3 Test organisms | 第50页 |
| 3．2 Methods | 第50-56页 |
| 3．2．1 Exposure of larvae to test chemicals for determination of susceptibility index | 第50-52页 |
| 3．2．2 Exposure of larvae to test chemicals for growth and survival | 第52-53页 |
| 3．2．3 Determination of catalase activity in silkworms, blood | 第53-54页 |
| 3．2．4 Determination of cocoon and cocoon shell weights of silkworms cocoons | 第54页 |
| 3．2．5 Collection of silkgland, and fatbodies for weight determination of 5~（th） instar poisoned silkworm larvae | 第54-56页 |
| 4． RESULTS AND ANNLYSIS | 第56-70页 |
| 4．1 Chromium susceptibility index number to chromium resistance of two silkworm races | 第56-58页 |
| 4．2 Influence of form and quantity of Cr ions on the development and survival of Qiufeng × Baiyu and Qingsong × Haoyue larvae | 第58-63页 |
| 4．3 Blood catalase activity of chromium-poisoned 5~（th） instar silkworm larvae | 第63-66页 |
| 4．4 Cocoon qualities due to different concentrations of Cr（Ⅲ） and Cr （Ⅵ） ions | 第66-67页 |
| 4．5 Silkgland and fatbody weights to varied concentrations of chromium （Ⅲ） and chromium （Ⅵ） ions | 第67-70页 |
| 5． DISUSSION | 第70-73页 |
| 6． CONCLUSIONS AND RECOMMENDATIONS | 第73-76页 |
| REFERENCES | 第76-82页 |
