University of Bath PHD Studies into the modification of herbicide activity by chemical safeners and synergists Polge, Nicholas D. Award date: 1989 Awarding institution: University of Bath Link to publication Alternative formats If you require this document in an alternative format, please contact: [email protected] General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 10. Oct. 2021 STUDIES INTO THE MODIFICATION OF HERBICIDE ACTIVITY BY CHEMICAL SAFENERS AND SYNERGISTS Submitted by Nicholas D Polge for the degree of Ph.D. of the University of Bath 1989 COPYRIGHT Attention is drawn to the fact that copyright of this thesis rests with its author. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with the author and that no quotation from the thesis and no information derived from it may be used without the prior written consent of the author. This thesis may be made available for consultation within the University Library and may be photocopied or lent to other libraries for the purposes of consultation. SIGNED: l\)icWk U UMI Number: U027882 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI U027882 Published by ProQuest LLC 2014. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 UfiiVEOSilY O f HATH LtBSAflY % -6FEBI95fl ! ] — ■« » « j*.1* & t j e^*ii6*»elnUAF*4ted S o 3 ^ ) 0 C CONTENTS Page ACKNOWLEDGEMENTS viii ABSTRACT ix ABBREVIATIONS xi 1. INTRODUCTION: WHY MODIFY HERBICIDE ACTION 1 1.1 HERBICIDES AND WEED CONTROL 1 1.2 DEVELOPMENT OF HERBICIDES 2 1.3 LIMITATIONS AND SHORTCOMINGS OF HERBICIDES 3 1.3.1 Improved Selectivity 3 1.3.2 Development of resistant weeds 6 1.3.3 Changes in crops and cropping systems 6 1.3.4 Environmental considerations 7 1.4 METHODS FOR DEVELOPING CHEMICAL WEED CONTROL 8 1.4.1 Improve application methods and formulation of products 8 1.4.2 Develop novel herbicide compounds 9 1.4.3 Genetic manipulation of crops to confer herbicide tolerance 10 1.4.4 Chemical manipulation of crop and weed tolerance to herbicides 12 ii. Page 2. HERBICIDE SAFENERS AND SYNERGISTS: LITERATURE REVIEW 14 2.1 TERMINOLOGY 14 2.2 HISTORY, DEVELOPMENT AND USES 17 2.2.1 Herbicide safeners 17 2.2.2 Herbicide synergists 23 2.3 MECHANISMS OF SAFENER ACTION 26 2.3.1 An overview 26 2.3.2 Alteration of herbicide uptake and translocation 30 2.3.3 Enhancement of herbicide detoxificiation 32 2.3.4 Physiological and competitiveantagonism of herbicides 44 2.4 MECHANISMS OF ACTION OF HERBICIDE SYNERGISTS 48 2.4.1 An overview 48 2.4.2 Specific examples 50 2.5 AIMS AND OBJECTIVES OF THIS STUDY 54 3. THE EFFECTS OF SELECTED HERBICIDE SAFENER AND HERBICIDE COMBINATIONS ON THE GERMINATION AND GROWTH OF ECHINOCHLOA CRUS-GALLI AND ZEA MAYS 57 3.1 INTRODUCTION 57 3.2 MATERIALS AND METHODS 60 3.2.1 Plant material 60 3.2.2 Soil and growth conditions 61 iii. Page 3.2.3 Chemicals and application rates 62 3.2.4 Experimental design 64 3.2.5 Data collection 65 3.2.6 Analysis of data 67 3.3 RESULTS 67 3.3.1 Experiment 1. Echinochloa crus-galli 67 3.3.2 Experiment 1. Maize 72 3.3.3 Experiment 2. Maize x chlorsulfuron x dichlormid 91 3.4 DISCUSSION 96 4. THE EFFECT OF NA AND DICHLORMID ON GLUTATHIONE AND GLUTATHIONE—S—TRANSFERASE LEVELS IN MAIZE 100 4.1 INTRODUCTION 100 4.2 MATERIALS AND METHODS 101 4.2.1 Plant material and growth conditions 101 4.2.2 Glutathione, GST and protein assays 102 4.2.3 Replication of experiments 105 4.3 RESULTS 105 4.3.1 Glutathione 105 4.3.2 GST 107 4.4 DISCUSSION 111 iv. Page 5. POTENTIAL MODULATORS OF GLUTATHIONE IN PLANTS: EFFECTS ON PISUM SATIVUM LEAF TISSUE AND INTERACTION WITH PARAQUAT 114 5.1 INTRODUCTION 114 5.2 MATERIALS AND METHODS 122 5.2.1 Plant material and test conditions 122 5.2.2. Chemicals 122 5.2.3 Glutathione assay 123 5.2.4 Chlorophyll and carotenoid determinations 123 5.2.5 Replication of experiments 124 5.3 RESULTS 124 5.3.1 Experiment 1. Glutathione modulation 124 5.3.2 Experiment 2. Effect of glutathione modulators on paraquat damage to pea leaf tissue 129 5.4 DISCUSSION 135 6. MODULATION OF GLUTATHIONE IN ZEA MAYS L. WITH BUTHIONINE SULFOXIMINE: INTERACTION WITH EPTC AND DICHLORMID 139 6.1 INTRODUCTION 139 6.2 MATERIALS AND METHODS 140 6.2.1 Plant material and growth conditions 140 6.2.2 Glutathione assay 141 V. Page 6.2.3 Growth measurements 141 6.2.4 Replication of experiments 142 6.3 RESULTS 142 6.4 DISCUSSION 152 7. THE EFFECT OF NA AND DICHLORMID TREATMENT OF MAIZE ON ACETOHYDROXYACID SYNTHETASE ACTIVITY, AND INHIBITION BY CHLORSULFURON 155 7.1 INTRODUCTION 155 7.2 MATERIALS ANDMETHODS 158 7.2.1 Plant material 158 7.2.2 AHAS extraction and assay 158 7.2.3 Protein assay 162 7.2.4 Chemicals 162 7.2.5 Replication of experiments 162 7.3 RESULTS 162 7.3.1 Effect of NA and dichlormid on extractable AHAS activity in maize 162 7.3.2 Effect of NA and dichlormid pretreatments on chlorsulfuron inhibition of AHAS extracted from plants 164 7.3.3 Effect of NA in vitro upon chlorsulfuron inhibition of AHAS 170 7.4 DISCUSSION 171 vi. Page 8. THE EFFECT OF NAPHTHALIC ANHYDRIDE ON THE GROWTH OF ZEA MAYS L. SUSPENSION CULTURES: INTERACTION WITH THE HERBICIDES METSULFURON-METHYL AND 2,4-D 175 8.1 INTRODUCTION 175 8.1.1 Comparison of herbicide toxicity and metabolism in plants and cell cultures 176 8.1.2 Summary of research into herbicide safeners using plant tissue cultures 179 8.1.3 Origin of Zea mays L. var. Black Mexican Sweet cell cultures, and use in herbicide safener research 183 8.1.4 Metsulfuron-methyl 184 MATERIALS AND METHODS 186 8.2.1 Zea mays L. var. Black Mexican Sweet: cell line 186 8.2.2 Culture media 186 8.2.3 Culturing 186 8.2.4 Chemicals 186 8.2.5 Time of treatments 187 8.2.6 Measurement of culture growth 187 8.2.7 Assessment of cell viability 188 8.2.8 Calcualtion of generation time of cultures 189 8.2.9 Replication of experiments 189 RESULTS AND DISCUSSION 190 8.3.1 Growth of Black Mexican Sweetcorn cultures 190 vii. Page 8.3.2 Response of BMS cultures to NA treatment 192 8.3.3 Response of BMS cultures to metsulfuron-methyl 204 8.3.4 Interactive effect of NA and metsulfuron- methyl upon the growth of BMS cell cultures 211 8.3.5 The effect of 2,4-D concentration upon the growth of BMS cell cultures: interaction with NA and metsulfuron-methyl 214 8.3.6 Some comments on the effect of acetone on cell culture growth 222 8.4 DISCUSSION 225 9. CONCLUDING DISCUSSION 233 REFERENCES 241 APPENDICES 274 ACKNOWLEDGEMENTS I would like to thank my supervisors Dr. Alan Dodge and Dr. John Caseley for their advice and constructive criticism throughout this research. I am also indebted to Gillian Arnold for help with statistical analysis of the data, to Bob Harvey and Pete Clark for the photography, and Tim Moxham for technical support. I wish to acknowledge the assistance of Dr. Roger Wallsgrove at Rothamsted with the AHAS assay techniques, and Dr. Joseph Kueh at Long Ashton with the tissue culture work. I am also grateful to Dr. John Thompson at Jealotts Hill for supplying the maize suspension culture. Finally I wish to thank friends and colleagues at Bath University and Long Ashton Research Station for their support and encouragement, the MAFF for the research studentship, and to Judy Harbutt for typing the thesis. ABSTRACT Initial growth trial investigations revealed that seed dressing with the safeners naphthalic anhydride (NA) and dichlormid would partially protect Zea mays L. var. LG 11 against pre-emergence applications of the sulfonylurea herbicide chlorsulfuron. The safeners flurazole and oxabetrinil were less effective. None of the safeners protected Z. mays against the imidazolinone herbicide imazapyr. NA, dichlormid and oxabetrinil did not protect Echinochloa crus-galli against these herbicides, or to the S-triazine atrazine or the chloroacetanilide metolachlor. Some initial delay of growth was associated with all safener applications, and flurazole also reduced germination rates in both species.