Ecology of Bradyrhizobium Japonicum in Iowa Soybean Rhizosphere Soil Patrick M

Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1986 Ecology of Bradyrhizobium japonicum in Iowa soybean rhizosphere soil Patrick M. Hicks Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agricultural Science Commons, Agriculture Commons, and the Agronomy and Crop Sciences Commons Recommended Citation Hicks, Patrick M., "Ecology of Bradyrhizobium japonicum in Iowa soybean rhizosphere soil " (1986). Retrospective Theses and Dissertations. 8252. https://lib.dr.iastate.edu/rtd/8252 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS While the most advanced technology has been used to photograph and reproduce this manuscript, the quality of the reproduction is heavily dependent upon the quality of the material submitted. For example: • Manuscript pages may have indistinct print. In such cases, the best available copy has been filmed. • Manuscripts may not always be complete. In such cases, a note will indicate that it is not possible to obtain missing pages. • Copyrighted material may have been removed from the manuscript. In such cases, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, and charts) are photographed by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each oversize page is also filmed as one exposure and is available, for an additional charge, as a standard 35mm slide or as a 17"x 23" black and white photographic print. Most photographs reproduce acceptably on positive microfilm or microfiche but lack the clarity on xerographic copies made from the microfilm. For an additional charge, 35mm slides of 6"x 9" black and white photographic prints are available for any photographs or illustrations that cannot be reproduced satisfactorily by xerography. 8703711 Hicks, Patrick M. ECOLOGY OF BRADYRHIZOBIUM JAPONICUM IN IOWA SOYBEAN RHIZOSPHERE SOIL Iowa State University PH.D. 1986 University Microfilms In t6rn &ti 0 nâl 300 N. zeeb Road, Ann Arbor, Ml 48106 Ecology of Bradyrhizobium japonicum in Iowa soybean rhizosphere soil by Patrick M. Hicks A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY Department: Agronomy Major: Soil Microbiology and Biochemistry Approved: Signature was redacted for privacy. In Charge of Major «Wrk Signature was redacted for privacy. F<w the Major Department Signature was redacted for privacy. Iowa State University Ames, Iowa 1986 il TABLE OF CONTENTS Page GENERAL INTRODUCTION 1 LITERATURE REVIEW 3 Inoculation and Establishment of Nonindigenous Strains of Bradyrhizobium .japonicum in Soil 3 Ecology of the Rhizosphere and Bradyrhizobium .japonicum Interactions 4 Mycorrhizae-Rhizobium-legume tripartite symbiosis 4 Rhizobium survival in soil 7 Correlation of Pseudomonas spp. with B. .japonicum serogroup dominance and soil reaction 14 Fast-growing soybean nodulating Rhizobium 16 SECTION I. EFFECTS OF P FERTILIZATION AND VA MYCORRHIZAE ON MODULATION OF SOYBEAN 19 ABSTRACT 20 INTRODUCTION 22 MATERIAL AND METHODS 24 P Fertilization 24 VAM Inoculation 26 RESULTS AND DISCUSSION 28 P Fertilization 28 VAM Inoculation 32 LITERATURE CITED 35 SECTION II. SEASONAL FLUCTUATIONS OF SOYBEAN RHIZO SPHERE MICROFLORA AND INFLUENCE ON BRADYRHIZOBIUM JAPONICUM 38 ABSTRACT 39 INTRODUCTION 40 MATERIALS AND METHODS 42 Rhizosphere Populations 42 Greenhouse Screening 45 iii Page RESULTS AND DISCUSSION 49 Rhizosphere Populations 49 Greenhouse Screening 52 Sterile soil 52 Nonsterile soil 53 CONCLUSIONS 56 LITERATURE CITED 57 SECTION III. BIOLOGICAL FACTOR INFLUENCING BRADY- RHIZOBIAL NODULE OCCUPANCY IN A HIGH pH SOIL 59 ABSTRACT 60 INTRODUCTION 61 MATERIALS AND METHODS 63 RESULTS AND DISCUSSION 66 SUMMARY 69 LITERATURE CITED 70 SUMMARY AND CONCLUSIONS 71 LITERATURE CITED 74 ACKNOWLEDGMENTS 80 APPENDIX A. EXPERIMENTAL DESIGN OF FAST-GROWING RHIZOBIUM NODULATION STUDY 81 APPENDIX B. RECOVERY OF FAST-GROWING RHIZOBIUM FROM SOYBEAN NODULES 82 APPENDIX C. EXPERIMENTAL DESIGN OF FAST-GROWING RHIZOBIUM N FIXATION STUDY 87 APPENDIX D. DINITROGEN FIXATION IN FAST-GROWING RHIZOBIUM ISOLATES AND BRADYRHIZOBIUM JAPONICUM USDA 110 88 1 GENERAL INTRODUCTION Soybeans are predominantly nodulated by Bradyrhizobium japonicum serogroup 123 in Midwestern noncalcareous soils and by 135 in calcareous soils (Damirgi et al., 1967; Ham et al., 1971b; Kapusta and Rowenhorst, 1973; Weaver and Frederick, 1974a, 1974b). The factors responsible for this phenomenon have remained undiscovered to date. If soil factors influence nodule occupancy, they could be physical, chemical, or bio logical. These studies sought to investigate possible microbiological inter actions (biological factors) responsible for the dominance of serogroups 123 and 135. The first section, entitled "Effects of P fertilization and VA mycorrhizae on nodulation of soybean," examined the influence of vesicular-arbuscular mycorrhiza and P fertilization on B. .japonicum 123 nodule occupancy in both field and greenhouse soils. This section con tains an Introduction, Materials and Methods, Results and Discussion, and Literature Cited subsections. Tables also are included in the text. This manuscript will be submitted to the Soil Science Society of America Journal for publication. The second section, entitled "Seasonal fluctuations of soybean rhizosphere microflora and influence on Bradyrhizobium .japonicum," was both a field survey of soybean rhizosphere microflora and two struc tured experiments that evaluated if bacterial isolates capable of stimulating B. japonicum 123 growth on artificial media could influence nodule occupancy in both sterile and nonsterile soil. This section has the same subsection format as Section 1 and also contains a Summary and 2 tables in the text. This manuscript also will be submitted to the Soil Science Society of America Journal for publication. The third section, entitled "Biological factor influencing brady- rhizobial nodule occupancy in a high pH soil," was a preliminary study investigating fluorescent pseudomonad populations and B. .japonicum serogroup 135 dominance in calcareous soils. This section has the same format as Sections 1 and 2, and also contains a Summary subsection. Tables also are included in the text. Future submission of this manu script for publication has not been determined at time of printing. These sections are followed by an overall summary and discussion of results. Additional literature used in the General Introduction, Literature Review, and the Summary and Conclusions are cited last. Appendix A is an outline of the experimental design used to test fast-growing rhizobial strain nodulation. Appendix B lists the raw data collected in this study. Appendix C is an outline of the experi mental design used to test fast-growing rhizobial strain fixation. Appendix D lists the raw data collected in this study. These data will be published as part of a manuscript submitted by the Department of Genetics, Iowa State University. 3 LITERATURE REVIEW Inoculation and Establishment of Nonindigenous Strains of Bradyrhizobium japonicum in Soil Most soybean growers in Iowa do" not inoculate seed prior to plant ing because it is questionable whether such practices actually do produce greater yields where indigenous populations of B. .japonicum are present (Elkins et al., 1976). In other areas of the U.S. where soybeans are grown, inoculation of seed is a common practice because of the relatively low cost of commercial inoculants and the potential for yield increases in these areas after inoculation. Inoculation is sometimes referred to as "cheap insurance" (Lynch and Sears, 1952) due to potential yield in creases balanced against relatively low costs of application. Ham et al. (1971a) reported that inoculating soybean seed with B. japonicum at planting in Iowa does not significantly increase yield. Seed yield is not increased because introduced rhizobia do not compete well with naturalized B. .japonicum serogroup 123. Johnson et al. (1965) demonstrated that only 5% of nodules were colonized by inoculant rhizobia on soybeans grown in soil containing indigenous rhizobial populations. The remaining nodules were produced by rhizobia established in soil prior to planting. Recoveries of inoculant rhizobia ranging from 0 to 17% were reported by Ham et al. (1971a). Massive inoculation may result in greater success in colonization of soybeans by introduced rhizobia. As much as 800 to 1000 times the usual inoculum rate may be required to achieve 50% of nodules produced from inoculant rhizobia. Boonkerd et al. (1978) obtained increased recoveries 4 of two strains of B. .japonicum by using inoculations of 10 to 100 times normal rate. Dunigan et al. (1984) determined that 3 years of massive soil inoculation with a nonindigenous strain of B. .japonicum resulted in the permanent establishment of the strain and eventually resulted in increased competitive ability with native rhizobia. Kapusta and Rowenhorst (1973) failed to produce significant increases in seed yield with massive inoculations but did improve recoveries

Load more