University of Plymouth PEARL https://pearl.plymouth.ac.uk 04 University of Plymouth Research Theses 01 Research Theses Main Collection 2002 The influence of extracts of Ascophvllum nodosum on plant and soil-borne pathogen interactions CUNHA, FELISBERTA MARIA JESUS http://hdl.handle.net/10026.1/2348 University of Plymouth All content in PEARL is protected by copyright law. Author manuscripts are made available in accordance with publisher policies. Please cite only the published version using the details provided on the item record or document. In the absence of an open licence (e.g. Creative Commons), permissions for further reuse of content should be sought from the publisher or author. The influence of extracts of Ascophvllum nodosum on plant and soil-borne pathogen interactions by FELISBERTA M ARIA JESUS CUNHA A thesis submitted to the University of Plymouth In partial fulfilment of the degree of DOCTOR OF PHILOSOPHY Faculty of Agriculture, Food & Land Use 2002 11 .~.::~.} (.. ··~·. ..... .. : ~; ....· ;· •j.. ' ~UNIVERSITY OF PLYMOUTH~ I I llom No. 9 .0 0 'S ~ ~ 1: 6 s- )( .! ' 1 f1~tq ;.2 ' I APR 200'i vll~ t~o.f-18r:s1S b..z&.:, , c~ cor·,u~ '!e ·L . .. .. _ l?lVMOUr:H U~!W ' -~- . I ABSTRACT Felisberta Maria Jesus Cunha The influence of extracts of Ascoplryllum nodosum on plant and soil-borne pathogen interactions This thesis presents an investigation into the responses to extracts of Ascophyllum nodosum (Maxicrop seaweed extracts - MSE) of two different plants species - wheat and strawberry, and their interactions with two soil-borne pathogens, Gaeumannomyces graminis and Phytophthora .fragariae respectively, under various environmental conditions. The responses to MSE using hydroponic, glasshouse and field experiments showed that levels of Take-all infection in wheat were reduced by some of the treatments applied. Repeat experiments showed that consistency of results was poor but a positive trend for disease suppression followed MSE treatments. Studies of strawberry infection by Phytophthora fragariae revealed a significantly reduced level of disease severity in plants grown both in hydroponics and in the growth chamber in response to MSE. In vitro studies of the fungus demonstrated that the seaweed extract treatments severely altered mycelial growth, which drastically reduced formation of sporangia and release of zoo spores. Experiments using ~-glucan, ~-glucanase and laminarin showed that these could not reproduce the effects observed for MSE treatments suggesting that these components were not responsible for the MSE effect. Applications of potassium salts however, did reproduce the responses observed when applied at concentrations similar to the ones found in the seaweed extract. In these investigations, no significant benefits to non-inoculated strawberry plants could be identified as a response to MSE. Measurement of growth of disease infected plants, however clearly demonstrated that they benefited in terms of growth from the MSE amendments probably as a consequence of the disease suppression obtained. iii CONTENTS COPYRIGHT STATEMENT (i) TITLE (ii) ABSTRACT (iii) CONTENTS (iv) (vii) LIST OF FIGURES (x) LIST OF TABLES (xi) LIST OF PLATES (xii) ACKNOWLEDGEMENTS (xiii) DECLARATION CHAPTER I- LITERATURE REVIEW I. PLANTS AND DISEASE 2 !.!.Impact of Disease on Plant Growth and Nutrition 5 1.2. Plant Defence Mechanisms 10 1.3. Soil-borne Plant Pathogens 13 2. PLANT PROTECTION STRATEGIES 14 2.1. Conventional Crop Protection Systems 17 2.2. Alternative Crop Protection Systems 19 -Seaweed Extracts as Biocontrol and Bio-stimulant Agents 28 -Aims of this Research Investigation IV CHAPTER II - STUDY OF THE INFLUENCE OF ASCOPHYLLUM 32 NODOSUMEXTRACTS ON THE GROWTH OF WHEAT AND ITS INTERACTIONS WITH GAEUMANNOMYCJS GRAMINIS Take-all- Gaeumannomycis graminis 32 I. Effect ofMaxicrop Concentrate Seaweed Liquid Extract on the growth of 35 Gaeumannomycis graminis in vitro 2. Effect ofMaxicrop Concentrate Seaweed Liquid Extract on Gaeumannomycis 42 graminis infection and wheat plant growth in hydroponics 3. Effect ofMaxicrop Concentrate Seaweed Liquid Extract on Gaeumannomycis 59 gram in is infection and wheat plant growth in the glasshouse 4. Investigation of wheat growth responses to Maxicrop seaweed extracts­ 75 Glasshouse Experiments 4.1.Conductivity and Chemical Analysis of Maxicrop seaweed extruded granules 75 4.2. Responses of wheat plants to Maxicrop seaweed extruded granules 80 4.3. Effect ofMaxicrop concentrate liquid seaweed extract on wheat plant growth 85 and protein production 5. Investigation of wheat and Take-all responses to Maxicrop seaweed extracts­ 99 Field Experiments 5 .I. Field Experiment I 99 5.2. Field Experiment 2 106 CHAPTER Ill- THE INFLUENCE OF ASCOPHYLLUM 112 NODOSUM EXTRACTS ON PLANT GROWTH AND PHYTOPHTHORA FRAGARIAE DISEASE OF STRAWHERRIES Red Core- Phytophthorafragariae 112 1. Effect ofMaxicrop Concentrate Seaweed Liquid Extract on the growth of 121 Phytophthorafragariae in vitro in solid medium 2. Response of Phytophthora fragariae to treatments with Maxicrop Concentrate 123 V 2. Response of Phylophthora fragariae to treatments with Maxicrop Concentrate 123 Seaweed Liquid Extract in Liquid Medium 3. Effect ofMaxicrop Concentrate Seaweed Liquid Extract on the growth of 151 Phytophthora fragariae infection of strawberries- Hydroponic Experiments 3.a. Hydroponic Experiment I 153 3.b. Hydroponic Experiment 2 157 4. Effect ofMaxicrop Concentrate Seaweed Liquid Extract on the growth of 160 Phytophthora fragariae infection of strawberries - Growth Chamber Experiments CHAPTER IV- GENERAL DISCUSSION 166 I. Investigation of responses to Maxicrop Seaweed Extracts by wheat and 170 Gaeumannomycis graminis. 2. Investigation of strawberry and Phytophthorafragariae responses to Maxicrop 177 Concentrate Seaweed Liquid extract OVERALL CONCLUSIONS 182 184 REFERENCES APPENDICES 207 APPENDIX I - Assessment keys 208 APPENDIX II - Example of Anova Analysis carried out in Excel 210 APPENDIX Ill -Summarized additional work developed through-out the PhD 211 Research Program vi LIST OF FIGURES Fig. 1.1- Effect of MLSE on Take-all of Wheat grown in hydroponics. 46 Fig. 1.2- Effect ofMLSE on Take-all of Wheat grown in hydroponics. 50 Fig. 1.3- Effect of MLSE applied with a soil and a Pseudomonas fluorescens 53 solution on Take-all of Wheat grown in hydroponics. Fig. 1.4- Effect ofMLSE on Take-all ofwheat in grown in hydroponics. 55 Fig. 1.5- Effect of treatments with MLSE on Gaeumannomycis gram in is of wheat 57 grown in hydroponics. Fig. 1.6.1- Effect ofMaxicrop seaweed extracts on Take-all of wheat. 65 Fig. 1.6.2- Effect of Maxicrop seaweed extracts on Wheat plants. 65 Fig. 1.6.3- Effect ofMaxicrop seaweed extracts on Wheat plants. 66 Fig. 1.6.4- Effect ofMaxicrop seaweed extracts on Wheat plants. 66 Fig. I. 7- Effect of MLSE on the growth of Wheat. 70 Fig. 1.8.1- Effect ofMLSE on Take-all of Wheat. 72 Fig. 1.8.2- Effect ofMLSE on Take-all of Wheat. 74 Fig. 1.9- Comparison between electric conductivity of KCI and EMG at 79 equivalent K concentrations. Fig. l.lO.a- Response of Wheat to increasing amounts ofEMG. 81 Fig. I.IO.b- Response of Wheat to increasing amounts ofEMG 82 Fig. I.IO.c- Response of Wheat to increasing amounts ofEMG 82 Fig. l.IO.d- Response of Wheat to increasing amounts ofEMG 83 Fig. 1.11 .a- Nitrogen content of wheat plants treated with MLSE. 92 Fig. l.ll.b- Potassium content of wheat plants treated with MLSE. 93 Fig. 1.11.c- Phosphorous content of wheat plants treated with MLSE. 94 Fig. l.ll.d- Effect of one MLSE treatment on protein band curves of wheat as 95 registered by densitometry. Fig. 1.11.e- Effect of multiple MLSE treatments on protein band curves of wheat 95 as registered by densitometry. Fig. 1.12.a- Effect of Maxicrop seaweed extracts on Take-all of wheat grown in I 03 the field; Winter assessment. vii Fig. 1.12.b- Effect of Maxicrop seaweed extracts on Take-all of wheat grown in 103 the field; Spring assessment. Fig. 1.12.c- Response of Wheat grown in the field to Maxicrop seaweed extracts; 104 Winter assessment. Fig. 1.12.d- Response of Wheat grown in the field to Maxicrop seaweed extracts; I 04 Winter assessment. Fig. 1.12.e- Response of Wheat grown in the field to Maxicrop seaweed extracts; 105 Spring assessment. Fig. 1.13.a- Effect of Maxicrop seaweed extracts on Take-all of wheat grown in 108 the field. Second Field Trial. Fig. 1.13.b- Response of Wheat grown in the field to Maxicrop seaweed extracts; 108 Second Field Trial. Fig. 1.13.c- Response of Wheat grown in the field to Maxicrop seaweed extracts; 109 Second Field Trial. Fig. 1.13 .d- Response of Wheat grown in the field to Maxicrop seaweed extracts; I 09 Second Field Trial. Fig. 2.1- Effect of treatment with MLSE on Phytophthora .fragariae production 130 of sporangia in soilless leachate (SL ). Fig. 2.2- Effect of dilution of Soilless leachate (SL) with DW on the production 132 of sporangia by Phytophthora .fragariae. Fig. 2.3- Effect ofMLSE on sporangia production by Phytophthora.fragariae in 134 non-diluted soilless leachate (SL). Fig. 2.4- Effect of treatments with MLSE and DW on Phytophthora .fragariae 137 sporangia production in soilless leachate. Fig. 2.5- Effect of treatments with MLSE and Potassium Chloride (KC!) on 139 Phytophthora .fragariae sporangia production in soilless leachate (SL ). Fig. 2.6- Effect of treatments with MLSE, Potassium Chloride (KCl) and 143 Potassium Phosphate (K2HP04) on Phytophthora .fragariae sporangia production in soilless leachate (SL). Fig. 2.7- Effect of treatments with MLSE and Beta-glucan (BG) on sporangia 145 production by Phytophthora.fragariae in soilless leachate. VIII Fig. 2.8- Effect of treatments with MLSE, beta-glucan (BG), Beta-glucanase and 148 Laminarin (L) on sporangia production by Phytophthora fragariae in Soilless Leachate (SL). Fig. 2.9.1.- Effect ofMLSE on Phytophthorafragariae symptoms on strawberry !54 plants - Hydroponics Experiment I. Fig. 2.9.2- Effect of MLSE on strawberry plants- Hydroponics Experiment 1.