Complex interactions based on host plant, rhizosphere microorganisms and soil microenvironment are presumed to be responsible for the suppressive properties of biochar against soil-borne diseases, although the underly...Complex interactions based on host plant, rhizosphere microorganisms and soil microenvironment are presumed to be responsible for the suppressive properties of biochar against soil-borne diseases, although the underlying mechanisms are not well understood. This study is designed to evaluate the efficacy of biochar amendment for controlling tomato bacterial wilt caused by Ralstonia solanacearum, and to explore the interactions between biochar-induced changes in rhizosphere compound composition, the pathogen and tomato growth. The results showed that biochar amendment decreased disease incidence by 61–78% and simultaneously improved plant growth. The positive ‘biochar effect' could be associated with enhanced microbial activity and alterations in the rhizosphere organic acid and amino acid composition. Specifically, elevated rhizosphere citric acid and lysine, but reduced salicylic acid, were induced by biochar which improved microbial activity and rendered the rhizosphere unsuitable for the development of R. solanacearum. In addition, nutrients which were either made more available by the stimulated microbial activity or supplied by the biochar could improve plant vigor and potentially enhance tomato resistance to diseases. Our findings highlight that biochar's ability to control tomato bacterial wilt could be associated with the alteration of the rhizosphere organic acid and amino acid composition, however, further research is required to verify these ‘biochar effects' in field conditions.展开更多
To search for an alternative for Nd_(2)Fe_(14)B,we have studied the electronic structures of R_(2)M_(14)B compounds,where R stands for rare-earth element and M for Mn,Fe,Co and Ni.By density functional theory(DFT),we ...To search for an alternative for Nd_(2)Fe_(14)B,we have studied the electronic structures of R_(2)M_(14)B compounds,where R stands for rare-earth element and M for Mn,Fe,Co and Ni.By density functional theory(DFT),we discuss the atomic coordination environment and partial density of states(PDOS)in detail,with the emphasis on the interaction between the six kinds of M sites and the R atoms.We systemically calculated the electronic structures of sixty R_(2)M_(14)B compounds to provide systematic and reliable results for explaining the origination of magnetism,which is important for further development of Nd_(2)Fe_(14)B based magnet materials.展开更多
To search for proper alternatives to improve the magnetic properties of Nd_(2)Fe_(14)B,using first-principles density functional theory calculations we have systematically studied the R_(2)M_(14)B(R=lanthanides from L...To search for proper alternatives to improve the magnetic properties of Nd_(2)Fe_(14)B,using first-principles density functional theory calculations we have systematically studied the R_(2)M_(14)B(R=lanthanides from La to Lu;M=Mn,Fe,Co,and Ni)compounds with the isomorphic structure of Nd_(2)Fe_(14)B.The results show that for rare-earth elements,Pr is the most suitable choice for considering as an alternative of Nd.As for the substitution of Fe in Nd_(2)Fe_(14) B by other transition-metal elements,Co is much more suitable than Mn and Ni because the latter two result in too significant reduction of the magnetic moment.展开更多
基金supported by the National Natural Science Foundation of China (31870420 and 41807084)the Natural Science Foundation of Guangdong Province, China (2017A030313177 and 2018A030310214)the Science and Technology Project of Guangdong Province, China (2019B030301007)。
文摘Complex interactions based on host plant, rhizosphere microorganisms and soil microenvironment are presumed to be responsible for the suppressive properties of biochar against soil-borne diseases, although the underlying mechanisms are not well understood. This study is designed to evaluate the efficacy of biochar amendment for controlling tomato bacterial wilt caused by Ralstonia solanacearum, and to explore the interactions between biochar-induced changes in rhizosphere compound composition, the pathogen and tomato growth. The results showed that biochar amendment decreased disease incidence by 61–78% and simultaneously improved plant growth. The positive ‘biochar effect' could be associated with enhanced microbial activity and alterations in the rhizosphere organic acid and amino acid composition. Specifically, elevated rhizosphere citric acid and lysine, but reduced salicylic acid, were induced by biochar which improved microbial activity and rendered the rhizosphere unsuitable for the development of R. solanacearum. In addition, nutrients which were either made more available by the stimulated microbial activity or supplied by the biochar could improve plant vigor and potentially enhance tomato resistance to diseases. Our findings highlight that biochar's ability to control tomato bacterial wilt could be associated with the alteration of the rhizosphere organic acid and amino acid composition, however, further research is required to verify these ‘biochar effects' in field conditions.
基金supported by the National Natural Science Foundation of China(No.21703248)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000)the STS program under cooperative agreement between Fujian Province and Chinese Academy of Sciences(No.2017T3004)。
文摘To search for an alternative for Nd_(2)Fe_(14)B,we have studied the electronic structures of R_(2)M_(14)B compounds,where R stands for rare-earth element and M for Mn,Fe,Co and Ni.By density functional theory(DFT),we discuss the atomic coordination environment and partial density of states(PDOS)in detail,with the emphasis on the interaction between the six kinds of M sites and the R atoms.We systemically calculated the electronic structures of sixty R_(2)M_(14)B compounds to provide systematic and reliable results for explaining the origination of magnetism,which is important for further development of Nd_(2)Fe_(14)B based magnet materials.
基金supported by the National Natural Science Foundation of China(No.21703248)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000)the STS program under cooperative agreement between Fujian Province and Chinese Academy of Sciences(No 2017T3004)。
文摘To search for proper alternatives to improve the magnetic properties of Nd_(2)Fe_(14)B,using first-principles density functional theory calculations we have systematically studied the R_(2)M_(14)B(R=lanthanides from La to Lu;M=Mn,Fe,Co,and Ni)compounds with the isomorphic structure of Nd_(2)Fe_(14)B.The results show that for rare-earth elements,Pr is the most suitable choice for considering as an alternative of Nd.As for the substitution of Fe in Nd_(2)Fe_(14) B by other transition-metal elements,Co is much more suitable than Mn and Ni because the latter two result in too significant reduction of the magnetic moment.
