[Objectives] This study was conducted to explore the interaction between nitrogen-fixing and phosphate-solubilizing strains and the optimal combination of different functional strains,in order to provide a theoretical...[Objectives] This study was conducted to explore the interaction between nitrogen-fixing and phosphate-solubilizing strains and the optimal combination of different functional strains,in order to provide a theoretical basis for the development of PGPR compound fertilizers suitable for local environment.[Methods] In this study,16S rDNA gene sequence analysis was used to identify fast-growing and competitive strains from pasture nodules and rhizosphere soils in Guizhou Province,and three representative Rhizobia and phosphorus-solubilizing bacteria were chosen for the test of bacterial combination when reducing 50% of nitrogen and 30% of phosphorus.The effects of different strain combinations on the plant height,root length,aboveground and underground biomass of Lotus corniculatus L.were investigated,and the total nitrogen and total phosphorus contents of the plants were determined.[Results] The mixed bacterial agents could promote the increase of root biomass,and the effects of A1,A3,B3 and C3 were the most obvious.The fresh weight and dry weight of the roots of L.corniculatus increased by 30.35%-168.45% and 26.43%-180.00%,respectively,and A3,B3,B2 and C3 had the best effects.The total phosphorus content of the plants increased by 12.79%-55.25% compared with the CK2;and most of the bacterial agents with significant growth-promoting effects showed decreased total nitrogen contents,while those with non-significant growth-promoting effects showed significantly-increased total nitrogen contents,which were not as much as the CK1.Comprehensively,the most productive combination was C3,namely R27-2 Rhinohizobium fredii and P33-3 Stenotrophomonas rhizophila.[Conclusions] This study can provide a theoretical basis for the production and promotion of bacterial fertilizers.展开更多
A simple and effective system for the transformation and regeneration of a leguminous plant has been developed. The cotyledon explants of Lotus corniculatus (var. Leo) were infected by Agrobacterium tumefaciens that c...A simple and effective system for the transformation and regeneration of a leguminous plant has been developed. The cotyledon explants of Lotus corniculatus (var. Leo) were infected by Agrobacterium tumefaciens that contained a non-oncogenic Ti plasmid vector. The vector carried a chimaeric npt-Ⅱ gene and a nopaline synthase gene (nos). On the selective medium that contained kanamycin, 40% of the explants formed buds within 3 weeks. Developed shoots were cut off and transferred to rooting medium. Normal-looking plants were recovered and grew well after being transplanted into soil, bloomed and set seeds. Foreign genes were integrated onto the L. corniculatus genome, expressed, and inherited through sexual reproduction, which was proven by nopaline detection, NPT-Ⅱ enzyme activity detection and DNA hybridization test of the transformed plants and the nopaline detection of the progeny.展开更多
The aim of this work was to study the effect of condensed tannins （CT） on the kinetic of gas production in vitro, on the three main species of Azorean pasture： Trifolium repens, Lotus corniculatus and Lolium perenn...The aim of this work was to study the effect of condensed tannins （CT） on the kinetic of gas production in vitro, on the three main species of Azorean pasture： Trifolium repens, Lotus corniculatus and Lolium perenne, using Quebracho extract as the source of CT, and also to calculate total tannins and condensed tannins on the species studied. Lotus corniculatus, Lolium perenne and Trifolium repens were tested in vitro with the inclusion of Quebracho extract in doses of 0%, 2.5% and 5% DM. The total content in tannins was determined in the 3 species. We have found, in comparison with standard tannic acid, that tannins exist in the flower of T. repens （0.81 equivalents of tannic acid） and in L .corniculatus （1.07 equivalents of tannic acid） but not in L .perenne （0 equivalents of tannic acid）. The concentration of condensed tannins in the 3 species was： 0.34 mg/mL for T. repens; 0.83 mg/mL for L. corniculatus and 0 mg/ml for L. perenne. We verified that a significant reduction （P 〈 0.05） of gas production happened for doses of 5% of CT in comparison with the other two concentrations： 0% and 2.5% of CT. The results of this study express a reduction of the fermentation rate, which implies a reduction of gas production, so, a reduction of methane emission to the atmosphere and an increase of exploitation of the protein by ruminants.展开更多
The information related with results of a project on germplasm characterization of three Lotus species, important as forage plants, curried out in five environments of the central-southern zone of Chile, was reviewed....The information related with results of a project on germplasm characterization of three Lotus species, important as forage plants, curried out in five environments of the central-southern zone of Chile, was reviewed. An evaluation was made of 12 L. corniculatus cultivars introduced from different parts of the world, as well as germplasm naturalized in Chile, being 11 accessions of L. tenuis and 21 accessions ofL. uliginosus collected from 33°S to 38°S and 38°S to 45°S, respectively. Phenological, morphological, and agronomical characters were evaluated. Nitrogen fixation in field conditions and concentrations of condensed tannins in herbage were also included. It is concluded that there are cultivars of high value in L. corniculatus introduced germplasm which can be recommended for different environments of the central zone of Chile, as well as for local species breeding programmes. Information obtained from L. tenuis and L. uliginosus accessions shows genetic variability within both species. L. tenuis germplasm is adapted to clay, medium-textured, or sandy soils with water restrictions and phosphorous deficiency. Therefore, characterized accessions could be used to breed cultivars for low input production systems in constrained environments. L. uliginosus accessions include genotypes collected in sites with acid soils and variable tannin content in plant tissues that may be promissory genetic materials for breeding programmes with the objective of producing cultivars for animal production systems for the wet and acid soils in the southern zone of the country.展开更多
基金Supported by Guizhou Province Science and Technology Support Program(QKHZC[2016]2504,[2019]2359)
文摘[Objectives] This study was conducted to explore the interaction between nitrogen-fixing and phosphate-solubilizing strains and the optimal combination of different functional strains,in order to provide a theoretical basis for the development of PGPR compound fertilizers suitable for local environment.[Methods] In this study,16S rDNA gene sequence analysis was used to identify fast-growing and competitive strains from pasture nodules and rhizosphere soils in Guizhou Province,and three representative Rhizobia and phosphorus-solubilizing bacteria were chosen for the test of bacterial combination when reducing 50% of nitrogen and 30% of phosphorus.The effects of different strain combinations on the plant height,root length,aboveground and underground biomass of Lotus corniculatus L.were investigated,and the total nitrogen and total phosphorus contents of the plants were determined.[Results] The mixed bacterial agents could promote the increase of root biomass,and the effects of A1,A3,B3 and C3 were the most obvious.The fresh weight and dry weight of the roots of L.corniculatus increased by 30.35%-168.45% and 26.43%-180.00%,respectively,and A3,B3,B2 and C3 had the best effects.The total phosphorus content of the plants increased by 12.79%-55.25% compared with the CK2;and most of the bacterial agents with significant growth-promoting effects showed decreased total nitrogen contents,while those with non-significant growth-promoting effects showed significantly-increased total nitrogen contents,which were not as much as the CK1.Comprehensively,the most productive combination was C3,namely R27-2 Rhinohizobium fredii and P33-3 Stenotrophomonas rhizophila.[Conclusions] This study can provide a theoretical basis for the production and promotion of bacterial fertilizers.
文摘A simple and effective system for the transformation and regeneration of a leguminous plant has been developed. The cotyledon explants of Lotus corniculatus (var. Leo) were infected by Agrobacterium tumefaciens that contained a non-oncogenic Ti plasmid vector. The vector carried a chimaeric npt-Ⅱ gene and a nopaline synthase gene (nos). On the selective medium that contained kanamycin, 40% of the explants formed buds within 3 weeks. Developed shoots were cut off and transferred to rooting medium. Normal-looking plants were recovered and grew well after being transplanted into soil, bloomed and set seeds. Foreign genes were integrated onto the L. corniculatus genome, expressed, and inherited through sexual reproduction, which was proven by nopaline detection, NPT-Ⅱ enzyme activity detection and DNA hybridization test of the transformed plants and the nopaline detection of the progeny.
文摘The aim of this work was to study the effect of condensed tannins （CT） on the kinetic of gas production in vitro, on the three main species of Azorean pasture： Trifolium repens, Lotus corniculatus and Lolium perenne, using Quebracho extract as the source of CT, and also to calculate total tannins and condensed tannins on the species studied. Lotus corniculatus, Lolium perenne and Trifolium repens were tested in vitro with the inclusion of Quebracho extract in doses of 0%, 2.5% and 5% DM. The total content in tannins was determined in the 3 species. We have found, in comparison with standard tannic acid, that tannins exist in the flower of T. repens （0.81 equivalents of tannic acid） and in L .corniculatus （1.07 equivalents of tannic acid） but not in L .perenne （0 equivalents of tannic acid）. The concentration of condensed tannins in the 3 species was： 0.34 mg/mL for T. repens; 0.83 mg/mL for L. corniculatus and 0 mg/ml for L. perenne. We verified that a significant reduction （P 〈 0.05） of gas production happened for doses of 5% of CT in comparison with the other two concentrations： 0% and 2.5% of CT. The results of this study express a reduction of the fermentation rate, which implies a reduction of gas production, so, a reduction of methane emission to the atmosphere and an increase of exploitation of the protein by ruminants.
文摘The information related with results of a project on germplasm characterization of three Lotus species, important as forage plants, curried out in five environments of the central-southern zone of Chile, was reviewed. An evaluation was made of 12 L. corniculatus cultivars introduced from different parts of the world, as well as germplasm naturalized in Chile, being 11 accessions of L. tenuis and 21 accessions ofL. uliginosus collected from 33°S to 38°S and 38°S to 45°S, respectively. Phenological, morphological, and agronomical characters were evaluated. Nitrogen fixation in field conditions and concentrations of condensed tannins in herbage were also included. It is concluded that there are cultivars of high value in L. corniculatus introduced germplasm which can be recommended for different environments of the central zone of Chile, as well as for local species breeding programmes. Information obtained from L. tenuis and L. uliginosus accessions shows genetic variability within both species. L. tenuis germplasm is adapted to clay, medium-textured, or sandy soils with water restrictions and phosphorous deficiency. Therefore, characterized accessions could be used to breed cultivars for low input production systems in constrained environments. L. uliginosus accessions include genotypes collected in sites with acid soils and variable tannin content in plant tissues that may be promissory genetic materials for breeding programmes with the objective of producing cultivars for animal production systems for the wet and acid soils in the southern zone of the country.
