Arbuscular Mycorrhizal Fungi Improve Salt And Drought Resistance To Processing Tomato And Study Of Their Mechanisms

Object: To screen the arbuscular mycorrhizal fungus strains which can improve processingtomato salt resistance and drought resistance. Furthermore, we would like to study the salt anddrought resistance mechanism of AM fungi.Methods: Processing tomato seedlings were incoulated with4different AM fungus(Glomus mosseae G.versiforme, G. intraradices and G.etunicatum) under salt-free conditionsand salt stress conditions (0.3%NaCl) in pots, then the growth effects and leaf physiologicalchanges were measured. The effects of2species AM fungi (G.mosseae, G.versiforme) on salttolerance and drought tolerance of processing tomato were studied in pot culture underdifferent NaCl concentrations (0%,0.3%, and0.5%) and different water stress conditions(Well watered, Water stressed-slight, and water stressed-heavy). At the same time, resistancemechanism was studied. The processing tomato yield and quality was affected by inoculationwith two AM fungi strains under different water gradient (normal water, mild water stress,and severe water stress) conditions through plug seedlings transplanting experiments.Results:1. The result show that the AM fungus could significantly enhance the processingtomato seedlings plant height, single leaf area, chlorophyll content, wet weight, dry weight,and shoots, roots N, P content. G. mosseae and G. versiforme were screened as the best strainsfor processing tomato growth, which increased dry weight by65%,60%, the N content ofshoots increased by66.48%,40.54%, the P content of shoots were increased by69.76%,79.06%over the control.2. The results showed that compared with non-mycorrhizal plant, mycorrhizal plantsignificantly enhanced root activity, promoted the accumulation of soluble sugar, solubleprotein in leaves and proline (Pro) content in roots, reduced accumulation of malondialdehyde(MDA) content. Superoxide dismutase (SOD) and POD activity in leaves were significantlypromoted than non-mycorrhizal plant. Expression of H+-PPase (AVP1) gene was studied byqRT-PCR and it was regulated by AM fungus and salt stress jointly. With the increasing of theconcentration of salt, the AVP1gene expression was decreased. But AVP1gene expression ofmycorrhizal plant higher than non-mycorrhizal plant distinctly.3. Plot experimental results showed that inoculation G.mosseae and G.versiforme toprocessing tomato could increase its hectare yield by2%-28%; reduce the soluble sugarcontent, lycopene content significantly; and control its umbilical rot, the max control effectscould reach24%under different water stress conditions.4. The results showed that compared with non-mycorrhizal plant, mycorrhizal plantsignificantly increased leaf chlorophyll content, enhanced SOD and catalase CAT activity;reduced Pro and MDA content in leaves under different water stress conditions. AVP1genewas studied by qRT-PCR and it was regulated by AM fungus and water stress jointly. With the increasing of water stress extent, the AVP1gene expression was decreased. But AVP1geneexpression of mycorrhizal plant higher than non-mycorrhizal plant distinctly. So theaccumulation of K+was increased, and the accumulation of Na+was decreased.Conclusion:1. Inoculation with G.mosseae and G.versiforme could increase biomass,chlorophyll content and leaf area and promote absorption of N, P elements, improveeffectively the salt tolerance of processing tomato. So it has good application prospects.2. Inoculation with G.mosseae and G.versiforme significantly enhanced nutrientabsorption capacity, alleviated poison of salt stress, improve resilience related enzyme activityand promoted the growth of processing tomato seedlings under different salt concentrations.3. Inoculation with G.mosseae and G.versiforme could significantly improve processingtomato fruit yield and quality. At the same time, it can control umbilical rot effectively undermild water stress and severe water stress conditions. This is help to implement large-scalemechanized processing tomato plug seedling transplanting techniques.4. Inoculation with G.mosseae and G.versiforme alleviated poison of water stress,improved resilience related enzyme activity, up-regulated related AVP1gene expression. Thus,significantly enhanced processing tomato seedlings nutrient absorption capacity and improvedits drought resistance, promoted the processing tomato seedling growth.