Two japonica rice （Oryza sativa L.） cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain （as high as a three-fold difference）, were compared for selenium （Se） accumulatio...Two japonica rice （Oryza sativa L.） cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain （as high as a three-fold difference）, were compared for selenium （Se） accumulation in their shoots when their growth media was supplied with different forms of Se. Results indicated that when treated with 0.25μmol L^-1 Na2SeO3, Xiushui 48 accumulation of Se in the shoots was significantly more rapid （P〈0.05） than S. Andrea, probably because of greater Se uptake and transport in Xiushui 48. Xiushui 48 rice seedlings had a higher shoot-Se accumulation rate and absorbed selenocysteine （Se-Cys） more rapidly than S. Andrea seedlings. However, when treated with Se as 0.25μmol L^-1 selenomethionine （Se-Met）, the S. Andrea seedlings＇ accumulation rate was significantly greater （P〈0.05） than that of Xiushui 48. Possibly, the high Se accumulation rate of Xiushui 48 seedling shoots compared to S. Andrea shoots was the result of a higher capacity of Xiushui 48 to transform selenite to organic Se compounds and a higher selenite uptake rate.展开更多
The dynamic changes in microbial diversity during the aerobic composting of agricultural crop straw with additives were evaluated using high-throughput sequencing at four phases of composting(mesophilic,thermophilic,c...The dynamic changes in microbial diversity during the aerobic composting of agricultural crop straw with additives were evaluated using high-throughput sequencing at four phases of composting(mesophilic,thermophilic,cooling and maturation phases).In addition,the physicochemical parameters of the composting system were determined in this study.The fermentation time of the thermophilic period was prolonged with the addition of urea or urea combined with a microbial agent.The ratio of C/N and germination index variation indicated that the additives were favorable for composting,because the additives directly changed the physicochemical properties of the compost and had effects on the diversity and abundance of bacteria and fungi.The abundance of operational taxonomic units(OTUs),diversity index(Shannon)and richness index(Chao1)of fungi and bacteria were found to significantly increase when urea+microbial agents were added to straw in the thermophilic phase.The relative abundance of the predominant bacteria and fungi at the phylum and genus levels differed during different composting phases.The abundance of the phyla Firmicutes and Proteobacteria declined in the order of treatments SNW>SN>S(S is straw only compost;SN is straw+5 kg t^(–1) urea compost;and SNW is straw+5 kg t^(–1) urea+1 kg t^(–1) microbial agent compost)in the thermophilic phase.The abundance of the genera Staphylococcus,Bacillus and Thermobifida followed the same order in the mesophilic phase.Ascomycota accounted for more than 92%of the total fungal sequences.With the progression of the composting process,the abundance of Ascomycota decreased gradually.The abundance of Ascomycota followed the order of S>SN>SNW during the thermophilic phase.The abundance of Aspergillus accounted for 4–59%of the total abundance of fungi and increased during the first two sampling periods.Aspergillus abundance followed the order of SNW>SN>S.Additionally,principal component analysis(PCA)revealed that the community compositions in the straw and straw+urea treatments were similar,and that the bacterial communities in treatments S,SN and SNW in the mesophilic phase(at day 1)were different from those observed in three other phases(at days 5,11,and19,respectively),while the fungal communities showed only slight variations in their structure in response to changes in the composting process.Canonical correlation analysis(CCA)and redundancy analysis(RDA)showed that total carbon(TC),NO_(3)^(–)-N(NN),electrical conductivity(EC)and p H were highly correlated with community composition.Therefore,this study highlights that the additives are beneficial to straw composting and result in good quality compost.展开更多
Rice is one of the main staple food crops in the world, but it may suffer serious water stress during growth period. Water stress during grain filling results in decreased grain yeild, but its mechanism generating and...Rice is one of the main staple food crops in the world, but it may suffer serious water stress during growth period. Water stress during grain filling results in decreased grain yeild, but its mechanism generating and scavenging the active oxygen is unclear under continuance of the water stress. The experiment was carried out in growth chamber to investigate the effects of water stress on the production of superoxide free radical （O2）, hydrogen peroxide （H202）, malondialdehyde （MDA）, reduced glutathione （GSH）, ascorbic acid （AsA）, and antioxidative enzyme activities in three rice hybrids with differing drought resistant under both normal and drought conditions during grain-filling stage. The results showed that water stress aggravated the membrane lipid peroxidation in rice leaves, which was more severe in less drought resistant hybrids than that in more tolerant ones. Also O2＇ and H2O2 accumulated more rapidly in less drought resistant hybrids than that in more tolerant ones. During water stress, decreases of GSH, AsA, chlorophyll, and relative water contents in more drought resistant hybrids were obvious less than those in less tolerant ones. Activities of superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD） in/eaves increased obviously in 0-14 d after heading and subsequently decreased rapidly, and those in more drought resistant hybrids were more than those in less tolerant ones. The results showed that changes of O2, H2O2, MDA, GSH, and AsA contents and antioxidative enzyme activities correlated significantly to drought resistance of rice hybrids, and more drought resistant hybrids possessed high ant oxidation capacity.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 40371063)the National Key Basic Research Support Foundation of China (No. G1999011808).
文摘Two japonica rice （Oryza sativa L.） cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain （as high as a three-fold difference）, were compared for selenium （Se） accumulation in their shoots when their growth media was supplied with different forms of Se. Results indicated that when treated with 0.25μmol L^-1 Na2SeO3, Xiushui 48 accumulation of Se in the shoots was significantly more rapid （P〈0.05） than S. Andrea, probably because of greater Se uptake and transport in Xiushui 48. Xiushui 48 rice seedlings had a higher shoot-Se accumulation rate and absorbed selenocysteine （Se-Cys） more rapidly than S. Andrea seedlings. However, when treated with Se as 0.25μmol L^-1 selenomethionine （Se-Met）, the S. Andrea seedlings＇ accumulation rate was significantly greater （P〈0.05） than that of Xiushui 48. Possibly, the high Se accumulation rate of Xiushui 48 seedling shoots compared to S. Andrea shoots was the result of a higher capacity of Xiushui 48 to transform selenite to organic Se compounds and a higher selenite uptake rate.
基金the National Key R&D Program of China(2017YFD0801304)the National Natural Science Foundation of China(31972943)。
文摘The dynamic changes in microbial diversity during the aerobic composting of agricultural crop straw with additives were evaluated using high-throughput sequencing at four phases of composting(mesophilic,thermophilic,cooling and maturation phases).In addition,the physicochemical parameters of the composting system were determined in this study.The fermentation time of the thermophilic period was prolonged with the addition of urea or urea combined with a microbial agent.The ratio of C/N and germination index variation indicated that the additives were favorable for composting,because the additives directly changed the physicochemical properties of the compost and had effects on the diversity and abundance of bacteria and fungi.The abundance of operational taxonomic units(OTUs),diversity index(Shannon)and richness index(Chao1)of fungi and bacteria were found to significantly increase when urea+microbial agents were added to straw in the thermophilic phase.The relative abundance of the predominant bacteria and fungi at the phylum and genus levels differed during different composting phases.The abundance of the phyla Firmicutes and Proteobacteria declined in the order of treatments SNW>SN>S(S is straw only compost;SN is straw+5 kg t^(–1) urea compost;and SNW is straw+5 kg t^(–1) urea+1 kg t^(–1) microbial agent compost)in the thermophilic phase.The abundance of the genera Staphylococcus,Bacillus and Thermobifida followed the same order in the mesophilic phase.Ascomycota accounted for more than 92%of the total fungal sequences.With the progression of the composting process,the abundance of Ascomycota decreased gradually.The abundance of Ascomycota followed the order of S>SN>SNW during the thermophilic phase.The abundance of Aspergillus accounted for 4–59%of the total abundance of fungi and increased during the first two sampling periods.Aspergillus abundance followed the order of SNW>SN>S.Additionally,principal component analysis(PCA)revealed that the community compositions in the straw and straw+urea treatments were similar,and that the bacterial communities in treatments S,SN and SNW in the mesophilic phase(at day 1)were different from those observed in three other phases(at days 5,11,and19,respectively),while the fungal communities showed only slight variations in their structure in response to changes in the composting process.Canonical correlation analysis(CCA)and redundancy analysis(RDA)showed that total carbon(TC),NO_(3)^(–)-N(NN),electrical conductivity(EC)and p H were highly correlated with community composition.Therefore,this study highlights that the additives are beneficial to straw composting and result in good quality compost.
基金supported by the National 863 Program of China (2002AA2Z4011)the Foundation for Personnel of Henan University of Science and Technology China.
文摘Rice is one of the main staple food crops in the world, but it may suffer serious water stress during growth period. Water stress during grain filling results in decreased grain yeild, but its mechanism generating and scavenging the active oxygen is unclear under continuance of the water stress. The experiment was carried out in growth chamber to investigate the effects of water stress on the production of superoxide free radical （O2）, hydrogen peroxide （H202）, malondialdehyde （MDA）, reduced glutathione （GSH）, ascorbic acid （AsA）, and antioxidative enzyme activities in three rice hybrids with differing drought resistant under both normal and drought conditions during grain-filling stage. The results showed that water stress aggravated the membrane lipid peroxidation in rice leaves, which was more severe in less drought resistant hybrids than that in more tolerant ones. Also O2＇ and H2O2 accumulated more rapidly in less drought resistant hybrids than that in more tolerant ones. During water stress, decreases of GSH, AsA, chlorophyll, and relative water contents in more drought resistant hybrids were obvious less than those in less tolerant ones. Activities of superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD） in/eaves increased obviously in 0-14 d after heading and subsequently decreased rapidly, and those in more drought resistant hybrids were more than those in less tolerant ones. The results showed that changes of O2, H2O2, MDA, GSH, and AsA contents and antioxidative enzyme activities correlated significantly to drought resistance of rice hybrids, and more drought resistant hybrids possessed high ant oxidation capacity.
