viii TABLE OF CONTENTS ABSTRACT LIST OF TABLES LIST OF FIGURES iii xxiii xxviii 1 INTRODUCTION 1 1.1 AIM AND SCOPE OF THE PRESENT INVESTIGATION 7 2 LITERATURE REVIEW 8 2.1 AN OVERVIEW OF TEA 8 2.2 TEA CULTIVATION IN SOUTHERN INDIA 9 2.3 BIOTIC AND ABIOTIC FACTORS FOR TEA PLANT GROWTH 9 2.4 ROLE OF FERTILIZERS IN TEA PLANTS 10 2.5 PLANT GROWTH REGULATORS IN TEA PLANTS 11 2.6 TEA DISEASES 11 2.7 RED ROOT DISEASE OF TEA PLANTS 13 2.8 PLANT GROWTH PROMOTING RHIZOBACTERIA: AN ALTERNATIVE APPROACH FOR CHEMICAL FERTILIZERS 15 2.9 MECHANISM OF PLANT GROWTH PROMOTING RHIZOBACTERIA AND ITS SIGNIFICANCE 16
ix 2.10 FLUORESCENT PSEUDOMONAS AS PLANT GROWTH PROMOTING RHIZOBACTERIA AND BIOCONTROL AGENTS 17 2.10.1 Pseudomonas fluorescens as Plant Growth Regulator and Phosphate solubilizer 18 2.10.2 Siderophore and Hydrogen Cyanide Production by Pseudomonas fluorescens 18 2.10.3 Antibiosis and Production of Antimicrobial Metabolites 19 2.10.4 Induced Systemic Resistance 20 2.10.5 Bioformulation of Pseudomonas fluorescens 21 3 MATERIALS AND METHODS 22 3.1 SURVEY OF RED ROOT ROT DISEASE 22 3.1.1 Collection of Infected Root Samples 23 3.2 ISOLATION, BIOCHEMICAL 23 CHARACTERIZATION AND MOLECULAR IDENTIFICATION OF PSEUDOMONAS SPP. FROM TEA SOILS 3.2.1 Site of soil collection 23 3.2.2 Edaphic and Environmental Analysis of Soil Samples 24 3.2.3 Determination of various Soil Edaphic Parameters 24 3.2.4 Estimation of Total Organic Carbon 24 3.2.5 Estimation of Total Nitrogen 25
3.2.6 Estimation of available Phosphorus and Exchangeable Potassium 25 3.2.7 Determination of Exchangeable Calcium, Sodium and Magnesium 25 3.2.8 Isolation of Pseudomonas spp. from Tea Soil 26 3.2.9 Biochemical Characterization of Pseudomonas spp. 26 3.2.10 Molecular Identification of Pseudomonas spp. 27 3.2.10.1 Isolation of genomic DNA from Pseudomonas fluorescens strains 27 3.2.10.2 Amplification, sequencing and RAPD analysis of DNA of Pseudomonas fluorescens strains 27 3.2.10.3 SDS PAGE analysis of protein pattern of Pseudomonas fluorescens strains 28 3.3 EFFECTS OF BIOTIC AND ABIOTIC FACTORS x
xi 3.3.3 Effects of different Carbon, Nitrogen, Amino acids and Vitamin Sources on Growth of Pseudomonas fluorescens Strains 30 3.3.4 Effects of different ph, Temperature, Light sources and NaCl Concentration on the growth of Pseudomonas fluorescens Strains 30 3.3.5 Antibiotic Resistance of Pseudomonas fluorescen Strains 31 3.4 IN VITRO TESTS FOR PLANT GROWTH PROMOTING TRAITS AND ANTAGONISTIC ACTIVITIES OF PSEUDOMONAS FLUORESCENS STRAINS 31 3.4.1 Estimation of Indole acetic acid 31 3.4.2 Detection of Indole acetic acid in Thin Layer Chromatography 32 3.4.3 Estimation of Gibberellic Acid 32 3.4.4 Siderophore Production 33 3.4.5 Phosphate Solubilisation 33 3.4.6 Hydrogen Cyanide Production 34 3.4.7 Ammonia Production 34 3.4.8 Salycylic Acid Production 34
xii 3.4.13 Extraction of Root Proteins and SDS-PAGE Analysis 36 3.4.14 Dual Culture Technique 37 3.4.15 Screening and Assay of Hydrolytic Enzymes 37 3.4.16 Efficiency of crude culture filtrate of Pseudomonas fluorescens against Poria hypolateritia through Food Poisoned Technique 39 3.4.17 Solvent Extraction of Crude Metabolites of Pseudomonas fluorescens VP5 strain against Poria hypolateritia by Agar well Diffusion Method 39 3.4.18 Characterization of Secondary Metabolites of Pseudomonas fluorescens VP5 Strain through Gas Chromatography- Mass Spectrometry Method 40 3.4.19 Sensitivity of selected Pseudomonas fluorescens Strains to Fungicides 41 3.4.20 Shelf -life of Pseudomonas fluorescens VP5 Strain in different Formulations 41 3.5 GREENHOUSE EXPERIMENTS 42 3.5.1 Preparation of Nursery Sleeves for Pathogen Induction and Treatment Application 42 3.5.2 Assessment of Disease Incidence and Disease Reduction 44 3.5.3 Measurement of Plant Growth Parameters 44
xiii 3.5.4 Analysis of Macroelements contents in Foliage 44 3.5.5 Analysis of Leaf Biochemical Constituents 45 3.6 RED ROOT ROT DISEASE MANAGEMENT THROUGH FIELD TRAIL EXPERIMENTS 46 3.6.1 Field Location 46 3.6.2 Selection of Fungicides and Botanicals 46 3.6.3 Preparation of Bioformulations 47 3.6.4 Disease assessment 49 3.6.5 Nutrient Status and Analysis of Soil Edaphic Parameters on Poria hypolateritia Infested Tea Soils 49 3.6.6 Soil Dehydrogenase and Leaf Nitrate Reductase Activity 49 3.6.7 Preparation of Leaf Material for Enzyme Extract 50 3.6.8 Assay of Phenolics and Phenolic Defensive Enzymes 51 3.6.9 Assay of Peroxidase, Polyphenol oxidase and Catalse 51 3.6.10 Assay of Chitinase, -1,3-glucanase and Protease 51 3.6.11 Enzyme Activity 52 3.6.12 Green Leaf Yield Assessment 52 3.6.13 Estimation of root carbohydrate 53 3.6.14 Response of Plant Growth Parameters 53
xiv 3.6.15 Physiological Variations 53 3.6.16 Determination of Biochemical Constituents 54 3.6.16.1 Estimation of total chlorophyll and carotenoids 54 3.6.16.2 Estimation of total sugars and total nitrogen 54 3.6.16.3 Estimation of total lipid 55 3.6.16.4 Estimation of total proteins 55 3.6.16.5 Estimation of total amino acids 55 3.6.16.6 Estimation of total polyphenols 56 3.6.16.7 Estimation of total catechins 56 3.6.17 Tea Quality 56 3.6.18 Statistical Analysis 57 4 RESULTS 58 4.1 SURVEY OF RED ROOT ROT DISEASE IN TEA PLANTATIONS 58 4.1.1 Influence of Environmental Parameters on the Population Density of Poria hypolateritia Obtained from Southern Indian Tea Plantations 61 4.1.2 Correlation of Population Density of Poria hypolateritia with Environmental Factors 63 4.1.2.1 Population density of Poria hypolateritia in Anamallais district 63
xv 4.1.2.2 Population density of Poria hypolateritia in Central Travancore district 64 4.1.2.3 Population density of Poria hypolateritia in High Range district 65 4.1.2.4 Population density of Poria hypolateritia in Nilgiris districts 65 4.1.2.5 Population density of Poria hypolateritia in Koppa district 66 4.2 ISOLATION, BIOCHEMICAL CHARACTERIZATION AND MOLECULAR IDENTIFICATION OF PSEUDOMONAS SPP. FROM SOUTHERN INDIA TEA SOILS 70 4.2.1 Influence of Edaphic and Environmental Parameters of Tea Soil Samples 70 4.2.2 Enumeration of Pseudomonas spp. from Tea Soil Samples 71 4.2.3 Impact of Seasonal Variation on the Population Dynamics of Pseudomonas spp. 74 4.2.4 Correlation of Bacterial Population Density with Edaphic and Environmental Factors 74 4.2.5 Morphological and Biochemical Characterization of Pseudomonas spp. 77 4.2.6 Molecular Identification of Pseudomonas spp. 81
xvi 4.2.7 Protein Profile of Pseudomonas fluorescens Strains 85 4.3 BIOTIC AND ABIOTIC FACTORS AFFECTING GROWTH OF PSEUDOMONAS FLUORESCENS STRAINS 86 4.3.1 Standardization of Media for Mass Multiplication of Pseudomonas fluorescens strains 86 4.3.2 Growth Kinetics Study of Pseudomonas fluorescens strains 87 4.3.3 Growth Trend of Pseudomonas fluorescens Strains in the Tea Ecosystem 87 4.3.4 Influence of different Carbon Sources on the growth of Pseudomonas fluorescens Strains 90 4.3.5 Impact of different Nitrogen Sources on the growth of Pseudomonas fluorescens Strains 91 4.3.6 Determination of the Abilty to Utilize different Amino Acids and Vitamins Sources by Pseudomonas fluorescens Strains 91 4.3.7 Effect of different ph and Temperature Regimes on the growth of Pseudomonas fluorescens Strains 93 4.3.8 Influence of different Light Sources on the growth of Pseudomonas fluorescens Strains 94
xvii 4.3.9 Growth response of Pseudomonas fluorescens Strains at different of Sodium Chloride Concentration 94 4.3.10 Plasmid Mediated Antibiotic Resistance Pattern of Pseudomonas fluorescens Strains Isolated from Tea Rhizosphere Soils 95 4.4 PLANT GROWTH PROMOTING TRAITS AND ANTAGONISTIC ACTIVITIES OF PSEUDOMONAS FLUORESCENS STRAINS 97 4.4.1 Study of Plant Growth Promoting Traits Exhibited by Pseudomonas fluorescens Strains under in vitro Conditions 97 4.4.2 Phosphatase Enzymes Produced by Pseudomonas fluorescens Strains from Southern India 101 4.4.3 Pathogen Isolation and Identification 102 4.4.4 Micromorphology of Poria hypolateritia 104 4.4.5 Protein Profiles of Healthy and Infected Roots 107 4.4.6 Antifungal Activity of Pseudomonas fluorescens Strains against Poria hypolateritia 108 4.4.6.1 Dual culture technique 108 4.4.6.2 Inhibitory effect of bacterial strains on fungal hyphal morphology 108 4.4.6.3 Hydrolytic enzymes secreted by Pseudomonas fluorescens strains 111
xviii 4.4.6.4 Effects of crude culture filtrates of Pseudomonas fluorescens strains on growth of Poria hypolateritia 114 4.4.6.5 Assessment of solvent extracts of crude metabolites of Pseudomonas fluorescens VP5 strain against Poria hypolateritia using an agar well diffusion method 115 4.4.7 Gas Chromatography Mass Spectrometry Analysis of Secondary Metabolites Produced by Pseudomonas fluorescens VP5 Strain 116 4.4.8 Compatibility of Fungicidal Resistance of Pseudomonas fluorescens Strains 117 4.4.9 Screening of suitable Carriers for Pseudomonas fluorescens VP5 Strain 119 4.5 EVALUATION OF FUNGICIDES AND BIOCONTROL AGENTS FOR CONTROL OF PORIA HYPOLATERITIA UNDER GREENHOUSE CONDITION 120 4.5.1 Management of Red Root Rot Infection by Applying Fungicides and Biocontrol Agents on Nursery Grown Tea Plants 120 4.5.2 Rooting Systems of Tea Clone in Response to the Application of Fungicides and Biocontrol Agents 120
xix 4.5.3 Influence of Fungicides and Biocontrol Agents on Plant growth Promotion of UPASI-9 Tea Clone 122 4.5.4 Impact of Fungicides and Bioformulations on Plant Growth Parameters 126 4.5.5 Analysis of Macronutrient status in Leaves of Tea Plants Treated with Fungicides and Biocontrol Agents 126 4.5.6 Impact of Fungicides and Biocontrol Treatments on Biochemical Constituents of Foliage 129 4.5.7 Population Dynamics of Biocontrol Agents in Pathogen Infested Soil Samples of Nursery Sleeves containing tea plants 130 4.6 EVALUATION OF INDIGENOUS PSEUDOMONAS FLUORESCENS AGAINST RED ROOT ROT DISEASE OF TEA PLANTS UNDER FIELD CONDITIONS 133 4.6.1 Influence of Fungicides, Botanicals and Biocontrol Agents on Nutrient Status and Analysis of Soil Edaphic Parameters on Red Root Infested Soils 133 4.6.2 Impact of Application of Fungicides and Biocontrol agents on Soil Dehydrogenase and Leaf Nitrate Reductase Activity in Treated and Untreated Poria hypolateritia -Infected Plants 135
xx 4.6.3 Phenolics and Phenolic Defensive Enzymes in Treated and Untreated Red Root Rot Infected Tea Plants 136 4.6.4 Differences in Redox Defensive Enzymes between Treated and Untreated Red Root Rot Infected Tea Plants 137 4.6.5 Stimulation of Pathogen-Related Enzymes in Treated and Untreated Red Root Rot Infected Tea Plants 139 4.6.6 Red Root Rot Disease Protection and Green Leaf Yield 142 4.6.7 Responses of Treated Plants to Fungicides and Biocontrol Agents 144 4.6.8 Physiological Responses of Treated Plants to Fungicides and Biocontrol Agents 144 4.6.9 Effects of Fungicides and Biocontrol Agents Application on Biochemical Parameters 147 4.6.10 Analysis of Tea Quality Parameters between Treated and Untreated Flush Shoots 147 4.6.11 Population Dynamics of Biocontrol Agents in field soil 151 5 DISCUSSION 152 5.1 RED ROOT ROT INCIDENCE IN SOUTHERN INDIA TEA PLANTATIONS 153
xxi 5.2 NUTRIENT STATUS AND POPULATION DENSITY OF FLUORESCENT PSEUDOMONAS SPP. IN TEA SOIL OF SOUTHERN INDIA 156 5.3 MORPHOLOGICAL, AND BIOCHEMICAL CHARACTERISTICS, AND MOLECULAR IDENIFICATION OF PSEUDOMONAS SPP. 157 5.4 EFFECT OF BIOTIC AND ABIOTIC FACTORS AFFECTING GROWTH OF PSEUDOMONAS FLUORESCENS STRAINS 158 5.5 IN VITRO PLANT GROWTH PROMOTING TRAITS OF PSEUDOMONAS FLUORESCENS STRAINS 161 5.6 IN VITRO ANTAGONISTIC ACTIVITIES OF PSEUDOMONAS FLUORESCENS STRAINS 163 5.7 EVALUATION OF EFFECTS OF INDIGENOUS PSEUDOMONAS FLUORESCENS STRAIN AGAINST PORIA HYPOLATERITIA UNDER GREENHOUSE CONDITION 165 5.8 EVALUATION EFFECTS OF INDIGENOUS PSEUDOMONAS FLUORESCENS STRAIN AGAINST RED ROOT ROT DISEASE OF TEA PLANTS UNDER FIELD CONDITIONS 167
xxii 6 CONCLUSIONS AND FUTURE WORK 171 APPENDIX 1 175 REFERENCES 181 LIST OF PUBLICATIONS 198 CURRICULUM VITAE 199
xxiii LIST OF TABLES TABLE NO. TITLE PAGE NO. 2.1 List of fungal root diseases and causal agents in tea plants 12 3.1 Treatment details of greenhouse experiments 43 3.2 Treatment details of field experiments 48 4.1 Mean red root rot incidence scores for tea clones and seedlines in different districts, from a survey of the disease carried out in tea plantations of southern India (PDI: %) 60 4.2 Classification of susceptibility of different tea clones and seedlines to red root rot, assessed in a survey of tea plantations in different planting districts of southern India 62 4.3 Average climatic parameters, and Poria hypolateritia soil populations, in different tea growing districts of southern India 63 4.4 Analysis of correlation coefficients between environmental parameters and population densities of Poria hypolateritia in Anamallais and Central Travancore tea planting districts 64 4.5 Analysis of correlation coefficients between environmental parameters and population densities of Poria hypolateritia in High Range and Nilgris planting districts 66
xxiv TABLE NO. TITLE PAGE NO. 4.6 Analysis of correlation coefficient between environmental parameters and population density of Poria hypolateritia in Koppa tea planting district 67 4.7 Mean edaphic parameters measured for different tea growing districts in southern India, and population densities of Pseudomonas spp. isolated from soils in these districts 72 4.8 Mean environmental parameters and population densities of Pseudomonas spp. isolated from tea plantations in different districts of southern India 73 4.9 Numbers and designations of Pseudomonas spp. isolated from soil samples collected from different locations of southern Indian tea plantations 75 4.10 Analysis of correlation coefficients of edaphic parameters in the Valparai tea plantation district with the population density of Pseudomonas spp. 76 4.11 Analysis of correlation coefficients of environmental parameters in the Valparai tea planting district with the population density of Pseudomonas spp. 77 4.12 Morphological features of Pseudomonas spp. isolated from southern Indian tea soils 79 4.13 Characteristic features of Pseudomonas isolates obtained from different southern Indian tea plantations 80 4.14 Accession numbers of Pseudomonas fluorescens strains submitted to NCBI, Maryland, USA 83 4.15 Mean optical density measurements for seven Pseudomonas fluorescens strains growing in liquid media containing different tea plant and tea soil extracts 89
xxv TABLE NO. TITLE PAGE NO. 4.16 Mean minimum inhibitory concentrations of antibiotic resistance profile of Pseudomonas fluorescens strains isolated from southern Indian tea rhizosphere soils 96 4.17 Mean amounts of indole acetic acid and gibberellic acid produced by different Pseudomonas fluorescens strains 99 4.18 Mean potential plant growth promoting characteristics measured from broth cultures of different Pseudomonas fluorescens strains 100 4.19 Mean sizes of red root rot lesions for Poria hypolateritia isolates, from different tea plantation districts 102 4.20 Mean radial growth of three Poria hypolateritia isolates on PDA plates for different periods 105 4.21 Culture characteristics of VP03 Poria hypolateritia isolate grown for different periods in potato dextrose agar plates 105 4.22 Mean linear growth (mm) of Poria hypolateritia colonies in dual culture plates with different Pseudomonas fluorescens strains 109 4.23 Mean specific activity of hydrolytic enzymes from Pseudomonas fluorescens strains on the third day of culture 113 4.24 Mean linear growth of Poria hypolateritia in PDA plates amended with crude extracts from Pseudomonas fluorescens broth cultures 114 4.25 Solvent extraction of crude metabolites of Pseudomonas fluorescens VP5 against Poria hypolateritia by agar well diffusion method 115
xxvi TABLE NO. TITLE PAGE NO. 4.26 Mass spectral analysis of data and names, formulae, molecular masses and potential activities of secondary metabolites produced by Pseudomonas fluorescens VP5 strain 117 4.27 Mean colony forming units of different Pseudomonas fluorescens strains assessed at different ppm concentration in six different fungicides 118 4.28 Mean numbers of colony forming units of Pseudomonas fluorescens VP5 in six different formulations during storage, assessed at different time intervals (days) after inoculation 119 4.29 Mean proportions of disease infection on UPASI-9 tea plants inoculated with Poria hypolateritia and treated with different fungicides and biocontrol bioformulations 121 4.30 Mean parameters of root development for tea clone UPASI-9, for plants treated with different fungicides and bioformulations. Soil EC and ph values are also presented for the different treatments 123 4.31 Mean tea plant parameters for plants grown in soil infested with Poria hypolateritia then treated with different fungicides or biocontrol treatments 127 4.32 Mean nutrient contents in leaves of tea plants grown in soil infested with Poria hypolateritia after treatment with different fungicides or biocontrol treatments 128 4.33 Mean contents of biochemical constituents of tea leaves from plants treated with different fungicides and biocontrol agents 131
xxvii TABLE NO. TITLE PAGE NO. 4.34 Different mean field soil parameters after treatment with different fungicides or biocontrol treatments. The field soil was naturally infested with Poria hypolateritia 136 4.35 Mean disease incidences and tea plant yield parameters for field-grown tea plants treated with different fungicides and biocontrol treatments. Yield is for the period 2008-2011 143 4.36 Mean plucking surface areas, numbers of plucking points, leaf moisture and internodal lengths for field-grown tea plants treated with different fungicides or biocontrol treatments, for tea bushes grown during the period 2008-2011 145 4.37 Mean physiological parameters in mother leaves of field-grown tea plants, treated with different fungicides and biocontrol treatments, for the period 2008-2011 146 4.38 Mean biochemical composition components measured in field-grown tea leaves from plants treated with different fungicides and biocontrol treatments, for the period during 2008-2011 148 4.39 Mean tea quality parameters for product harvested from field-grown tea plants treated with different fungicides or biocontrol treatments, for the period 2008-2011 149 4.40 Assessments and mean values of tea liquor characteristics from tea harvested from field-grown tea plants treated with different fungicides or biocontrol treatments, for the period 2008-2011 150
xxviii LIST OF FIGURES FIGURE NO. TITLE PAGE NO. 1.1 Symptoms of red root rot 4 3.1 Fungicides and biocontrol agents treated UPASI- 9 tea clone grown on nursery sleeves 45 4.1 Analysis of correlation coefficients between environmental parameters and population density of Poria hypolateritia in Anamallais tea planting district (Response surface methodology analysis) 67 4.3 Analysis of correlation coefficients between environmental parameters and population density of Poria hypolateritia in High Range tea planting district (Response surface methodology analysis) 68 4.5 Analysis of correlation coefficients between environmental parameters and population density of Poria hypolateritia in Koppa tea planting district (Response surface methodology analysis) 69 4.6 Seasonal variation of soil population densities of Pseudomonas spp. in southern Indian tea plantations 76 4.7A Cultural characteristics of representative Pseudomonas strains obtained from different agroclimatic zones of southern Indian tea plantations 78 4.7B Micrographs of cells Pseudomonas spp. 79 4.8(a) Agarose gel showing genomic DNA banding patterns of six Pseudomonas strains 81 4.8(b) Amplified PCR products of six Pseudomonas strains isolated from southern India tea plantations 82
xxix FIGURE NO. TITLE PAGE NO. 4.9(A) RAPD gel patterns of Pseudomonas fluorescens isolated from southern Indian tea plantations 84 4.9(B) Dendrogram showing the genetic relationship among six Pseudomonas fluorescens strains based on RAPD analysis 84 4.10 Protein profile of Pseudomonas fluorescens strains 85 4.11 Mean populations of different Pseudomonas fluorescens strains grown on different broth media 86 4.12 Optical density measurements for selected six Pseudomonas fluorescens strains growing in King s B medium 88 4.13 Mean optical density values for Pseudomonas fluorescens strains growing in liquid media containing different carbon sources 90 4.14 Mean optical density values for Pseudomonas fluorescens strains growing on liquid media containing different nitrogen sources 91 4.15 Mean optical density values for Pseudomonas fluorescens strains growing on liquid media containing different amino acids and vitamins 92 4.16 Mean optical density values for Pseudomonas fluorescens strains growing on liquid media at different ph and temperature 93 4.17 Mean optical density values for Pseudomonas fluorescens strains growing on liquid media at different light sources 94 4.18 Mean optical density values for Pseudomonas fluorescens strains growing on liquid media containing different sodium chloride concentration 95
xxx FIGURE NO. TITLE PAGE NO. 4.19 In vitro plant growth promoting traits exhibited by Pseudomonas fluorescens strains 98 4.20 Thin layer chromotography of indole acetic acid production by different Pseudomonas fluorescens strains detected by Salkowski reagent 99 4.21 Mean amounts of acid and alkaline phosphatases produced by different Pseudomonas fluorescens strains 101 4.22 Poria hypolateritia infected various parts of tea root system 103 4.23 Isolation of pathogen from infected tea root 104 4.24 Growth patterns of Poria hypolateritia in solid medium 105 4.25 Micromorphology of Poria hypolateritia observed under microscope 106 4.26 Mean mycelium dry weight for three Poria hypolateritia isolates (VP03, MP01 and KP05) growing for different periods in liquid medium 106 4.27 SDS-PAGE analysis of protein profiles from roots of healthy and Poria hypolateritia infected tea plants 107 4.28 Dual culture plates of Poria hypolateritia (left hand white colonies) and different Pseudomonas fluorescens strains (VP5 to MTCC; right hand streaks) at 7, 14, 21 days after inoculation of plates. Three control plates (no Pseudomonas fluorescens) are shown at the extreme right 110 4.29 Probable action of cell wall degrading enzymes on mycelium of Poria hypolateritia in dual cultures 111 4.30 Zones of inhibition around Pseudomonas fluorescens colonies on plates testing for different hydrolytic enzymes 112
xxxi FIGURE NO. TITLE PAGE NO. 4.31 Mean amounts of different hydrolytic enzymes produced by different Pseudomonas fluorescens strains 113 4.32 Gas chromatography mass spectrometry chromatogram of secondary metabolites produced by Pseudomonas fluorescens VP5 for antifungal activity 116 4.33 Mean root and shoot parameters for UPASI-9 tea plants grown in soil infested with Poria hypolateritia, after treatment with different fungicides or potential biocontrol agents 124 4.34 Mean plant dry weight, plant strength, total number branches and leaves for UPASI-9 tea plants grown in soil infested with Poria hypolateritia, after treatment with different fungicides or potential biocontrol agents 125 4.35 Mean proportions of amino acids (a), polyphenol and catechin (b) in tea leaves from plants treated with fungicides and biocontrol agents 132 4.36 Mean populations of biocontrol organisms in tea soil samples during 2008-2010 132 4.37 Mean total soil microbial activity (mg CO 2 produced; a) and mean leaf nitrate reduction (µmol of NO 2 /g FW/h; b), after different treatments were applied to field soil infested with Poria hypolateritia 136 4.38 Mean amounts of phenolics (a), trans cinnamic acid (b) and P-coumaric acid (c) in leaves from red root infected tea plants after treatment with different fungicides and biocontrol agents 138
xxxii FIGURE NO. TITLE PAGE NO. 4.39 Mean values of the redox defensive enzymes peroxidase (a), polyphenol oxidase (b) and catalase (c) in leaves from red root tea plants after treatment with different fungicides and biocontrol treatments 140 4.40 Mean values of pathogen related enzymes chitinase (a), -1,3- glucanse (b) and protease (c) in leaves from red root infected tea plants after treatment with different fungicides and biocontrol treatments 141 4.41 Mean numbers of individual biocontrol agents in field soils sampled at different periods after treatment with three different biocontrol agents 151