The tolerance of a restorer line R1056 of rice and its hybrid combinations to high temperature at flowering stage was evaluated by sowing them at three dif- ferent dates and transplanting them into a greenhouse equipp...The tolerance of a restorer line R1056 of rice and its hybrid combinations to high temperature at flowering stage was evaluated by sowing them at three dif- ferent dates and transplanting them into a greenhouse equipped with heating system at flowering stage. Several important agronomic traits of these rice varieties or combinations were also measured. The results revealed that treated by high temper- ature (38 ℃) at flowering stage, the seed setting rate (70.4%), percentage of dehis- cent anthers (75.5%), and pollen number per floret (78) of R1056 were close to those of N22, which is tolerant to high temperature, and significantly higher than those of the rice varieties sensitive to high temperature. The seed setting rate, per- centage of dehiscent anthers, and pollen number per floret of the hybrid combina- tions generated from R1056 were smaller than those of R1056, but higher than those of the rice varieties sensitive to high temperature. R1056 had excellent agro- nomic traits, and good combining ability, and its hybrid combinations had low plant height, numerous panicles and high yield, suggesting that R1056 is not only an ex- cellent rice variety with tolerance to high temperature, but also an excellent restorer in three-line hybrid rice breeding.展开更多
Two heat-tolerant rice varieties, N5 and TQ, were chosen as test materi- als. Specifically, rice seedlings (leaf age at 2.1), cultivated in room, were treated at 40 ℃ for 7 d and some indices were measured, includi...Two heat-tolerant rice varieties, N5 and TQ, were chosen as test materi- als. Specifically, rice seedlings (leaf age at 2.1), cultivated in room, were treated at 40 ℃ for 7 d and some indices were measured, including plant height, dry weight, leaf color, proline, malondialdehyde and conductivity. The results showed that high temperature advanced the growth of N5 seedlings, for example, plant height, root length and dry weight of ground parts all increased. However, high temperature prevented TQ seedlings growth, plant height in particular. Furthermore, high temper- ature treatment increased the content of chlorophyll of N5 and had none effects on PSII of N5, with little damages on membrane system. On the other hand, high temperature actually reduced PSII activity of TQ, and seriously damaged TQ mem- brane system. It is speculated that the differences of the two varieties lie on pro- duction or removing capacity of reactive oxide species.展开更多
The aim of this experimental work is to select wheat progenies tolerant high levels of salinity. Studies were conducted to determine the realized response in salt tolerance of some selected progeny (F3) through one ...The aim of this experimental work is to select wheat progenies tolerant high levels of salinity. Studies were conducted to determine the realized response in salt tolerance of some selected progeny (F3) through one cycle of screening and selection and the extent of variability for salt tolerance among selected progeny (F3) of wheat. All the selected progeny (F3) derived from (F2) populations after exposure are to high salinity level, were tested for salt tolerance during all growth stages in sand cultures salinized with 0, 100, 175 mM NaCI as compared with the unselected progeny (F2). Results showed that the selected progeny (F3) were in all cases except one, superior in yield at maturity and in most cases significantly so, both at 100 and 175 mM NaCl, to the yield of the unselected progeny (F2) controls. In this study, some selected progeny exhibited more than twice the seed yield compared with that obtained from unselected progeny at 175 mM NaCl, and their seed yield was also significantly higher than that at 0 mM NaCl. Results also indicated that the highest value percentage of realized response in salt tolerance was in (F3AS1) and (F3AS2) at 175 mM NaCI. It is important to bear in mind that the significant improvement in selected progeny was achieved just in a single cycle of selection. There is then a strong possibility that further increases in tolerance may be obtained through further cycles of selection till reaching F6 or F7 where would show genetics stability.展开更多
Recent studies have suggested that there may be a link between the use of in-feed antibiotics and the prevalence of antibiotic-resistant bacteria in human infections. It is believed that anaerobic digestion is a poten...Recent studies have suggested that there may be a link between the use of in-feed antibiotics and the prevalence of antibiotic-resistant bacteria in human infections. It is believed that anaerobic digestion is a potent method to reduce the antibiotic resistant bacteria present in waste from concentrated animal feeding operations. Cefazolin is a β-1actam antibiotic that is frequently used to treat the cows with mastitis in the Obihiro University herd. Disposal of untreated milk containing cefazolin residues promotes the occurrence of cefazolin resistant bacteria in the vicinity of farm, thus the objective of this study was to investigate the survival of antibiotic resistant bacteria in co-digestion of dairy manure and waste milk obtained from cows treated for mastitis with cefazolin under thermophilic conditions (55 ~C). Cow manure, digested slurry and waste milk (cefazolin residue concentration 2.17 mg/L) were used as the materials in order to have three digester contents; 100% slurry, 50% slurry + 50% manure and 50% slurry + 45% manure + 5% waste milk. The experiment was carried out using batch digesters (1 L) with active volume of 800 mL at 55 ℃ for 20 days to determine the survival of cefazolin resistant bacteria and to observe the digester performance by determining the bio gas and methane yield using gas chromatpgrapby. Dilution plate method was used to determine the population densities of total and cefazolin resistant bacteria at 0, 10th and 20th day of digestion. Total and cefazolin resistant bacterial counts were reduced with time by several orders until 10th day of digestion and those were almost similar at day 20th. Highest daily biogas and methane yield were observed in the digester contained slurry, manure and waste milk during early digestion period (until 5th day). The results suggest that thermophilic co-digestion of dairy manure and waste milk would be a suitable technology for reducing antibiotic (cefazolin) resistant bacteria while obtaining better digester performance.展开更多
Cement improves properties of soil materials, such as durability, stiffness, strength and moisture susceptibility. Each of them needs different cement contents that might not be suitable for other properties. Typicall...Cement improves properties of soil materials, such as durability, stiffness, strength and moisture susceptibility. Each of them needs different cement contents that might not be suitable for other properties. Typically, high cement content is desirable for durability, but not for shrinkage and cracking issues on the surface. Thus, improving durability with low cement content while complying with other requirements is an ideal aim, which may be achieved by pozzolanic supplementary products. Pozzolans contribute in hydration reactions and optimise cement consumptions in favour of durable and low shrinkage products. In this paper, the mixes of nano-silica and fly ash are considered to investigate their effect on strength, durability and shrinkage of modified CRB (crushed rock base) material. In the end, the benefits and features of nano-silica as a pozzolanic material will be focused and discussed more for effective cement consumption in soils.展开更多
Salinity of soils or water poses an increasing threat to food production due to climate change. Plant breeding programs were applied to improve salt tolerance in new wheat genotypes to overcome this problem. The aim o...Salinity of soils or water poses an increasing threat to food production due to climate change. Plant breeding programs were applied to improve salt tolerance in new wheat genotypes to overcome this problem. The aim of this research work is to estimate the realized improvement in salt tolerance of the selected genotypes through plant breeding programs. The comparison experiments were conducted in salinized soils at two locations for two years as compared with two local cultivars. All the selected genotypes derived from F2 populations after six cycles of exposure to high salinity level were tested for salt tolerance during all growth stage. At harvest stage, seed yield and its components were studied for the comparison. Results showed that there were significant differences between all selected genotypes and local eultivars in their overall sensitivities to soil salinity. All selected genotypes were superior in seed yield and its components at maturity to those of the local cultivars at the two location and years. Clearly, all the selected genotypes exhibited more than twice seed yield/m2 compared with that obtained from local cultivars. The results also indicated that there were differences among selected genotypes in their responses to soil salinity between locations and years, but not significant. Important thing is significant improvement in selected genotypes was achieved in their salt tolerance through six cycles of screening and selection to high salinity level. The conclusion is a strong possibility to improve salt tolerant genotypes of wheat with high salt tolerance through plant breeding programs.展开更多
基金Supported by the Fund from Agricultural Science and Technology Innovation Center of Hubei Province(2007-620-001-003)Key Project of Natural Science Foundation of Hubei Province(2014CFA103)~~
文摘The tolerance of a restorer line R1056 of rice and its hybrid combinations to high temperature at flowering stage was evaluated by sowing them at three dif- ferent dates and transplanting them into a greenhouse equipped with heating system at flowering stage. Several important agronomic traits of these rice varieties or combinations were also measured. The results revealed that treated by high temper- ature (38 ℃) at flowering stage, the seed setting rate (70.4%), percentage of dehis- cent anthers (75.5%), and pollen number per floret (78) of R1056 were close to those of N22, which is tolerant to high temperature, and significantly higher than those of the rice varieties sensitive to high temperature. The seed setting rate, per- centage of dehiscent anthers, and pollen number per floret of the hybrid combina- tions generated from R1056 were smaller than those of R1056, but higher than those of the rice varieties sensitive to high temperature. R1056 had excellent agro- nomic traits, and good combining ability, and its hybrid combinations had low plant height, numerous panicles and high yield, suggesting that R1056 is not only an ex- cellent rice variety with tolerance to high temperature, but also an excellent restorer in three-line hybrid rice breeding.
基金Supported by National Natural Science Foundation of China(30771156,31200387)~~
文摘Two heat-tolerant rice varieties, N5 and TQ, were chosen as test materi- als. Specifically, rice seedlings (leaf age at 2.1), cultivated in room, were treated at 40 ℃ for 7 d and some indices were measured, including plant height, dry weight, leaf color, proline, malondialdehyde and conductivity. The results showed that high temperature advanced the growth of N5 seedlings, for example, plant height, root length and dry weight of ground parts all increased. However, high temperature prevented TQ seedlings growth, plant height in particular. Furthermore, high temper- ature treatment increased the content of chlorophyll of N5 and had none effects on PSII of N5, with little damages on membrane system. On the other hand, high temperature actually reduced PSII activity of TQ, and seriously damaged TQ mem- brane system. It is speculated that the differences of the two varieties lie on pro- duction or removing capacity of reactive oxide species.
文摘The aim of this experimental work is to select wheat progenies tolerant high levels of salinity. Studies were conducted to determine the realized response in salt tolerance of some selected progeny (F3) through one cycle of screening and selection and the extent of variability for salt tolerance among selected progeny (F3) of wheat. All the selected progeny (F3) derived from (F2) populations after exposure are to high salinity level, were tested for salt tolerance during all growth stages in sand cultures salinized with 0, 100, 175 mM NaCI as compared with the unselected progeny (F2). Results showed that the selected progeny (F3) were in all cases except one, superior in yield at maturity and in most cases significantly so, both at 100 and 175 mM NaCl, to the yield of the unselected progeny (F2) controls. In this study, some selected progeny exhibited more than twice the seed yield compared with that obtained from unselected progeny at 175 mM NaCl, and their seed yield was also significantly higher than that at 0 mM NaCl. Results also indicated that the highest value percentage of realized response in salt tolerance was in (F3AS1) and (F3AS2) at 175 mM NaCI. It is important to bear in mind that the significant improvement in selected progeny was achieved just in a single cycle of selection. There is then a strong possibility that further increases in tolerance may be obtained through further cycles of selection till reaching F6 or F7 where would show genetics stability.
文摘Recent studies have suggested that there may be a link between the use of in-feed antibiotics and the prevalence of antibiotic-resistant bacteria in human infections. It is believed that anaerobic digestion is a potent method to reduce the antibiotic resistant bacteria present in waste from concentrated animal feeding operations. Cefazolin is a β-1actam antibiotic that is frequently used to treat the cows with mastitis in the Obihiro University herd. Disposal of untreated milk containing cefazolin residues promotes the occurrence of cefazolin resistant bacteria in the vicinity of farm, thus the objective of this study was to investigate the survival of antibiotic resistant bacteria in co-digestion of dairy manure and waste milk obtained from cows treated for mastitis with cefazolin under thermophilic conditions (55 ~C). Cow manure, digested slurry and waste milk (cefazolin residue concentration 2.17 mg/L) were used as the materials in order to have three digester contents; 100% slurry, 50% slurry + 50% manure and 50% slurry + 45% manure + 5% waste milk. The experiment was carried out using batch digesters (1 L) with active volume of 800 mL at 55 ℃ for 20 days to determine the survival of cefazolin resistant bacteria and to observe the digester performance by determining the bio gas and methane yield using gas chromatpgrapby. Dilution plate method was used to determine the population densities of total and cefazolin resistant bacteria at 0, 10th and 20th day of digestion. Total and cefazolin resistant bacterial counts were reduced with time by several orders until 10th day of digestion and those were almost similar at day 20th. Highest daily biogas and methane yield were observed in the digester contained slurry, manure and waste milk during early digestion period (until 5th day). The results suggest that thermophilic co-digestion of dairy manure and waste milk would be a suitable technology for reducing antibiotic (cefazolin) resistant bacteria while obtaining better digester performance.
文摘Cement improves properties of soil materials, such as durability, stiffness, strength and moisture susceptibility. Each of them needs different cement contents that might not be suitable for other properties. Typically, high cement content is desirable for durability, but not for shrinkage and cracking issues on the surface. Thus, improving durability with low cement content while complying with other requirements is an ideal aim, which may be achieved by pozzolanic supplementary products. Pozzolans contribute in hydration reactions and optimise cement consumptions in favour of durable and low shrinkage products. In this paper, the mixes of nano-silica and fly ash are considered to investigate their effect on strength, durability and shrinkage of modified CRB (crushed rock base) material. In the end, the benefits and features of nano-silica as a pozzolanic material will be focused and discussed more for effective cement consumption in soils.
文摘Salinity of soils or water poses an increasing threat to food production due to climate change. Plant breeding programs were applied to improve salt tolerance in new wheat genotypes to overcome this problem. The aim of this research work is to estimate the realized improvement in salt tolerance of the selected genotypes through plant breeding programs. The comparison experiments were conducted in salinized soils at two locations for two years as compared with two local cultivars. All the selected genotypes derived from F2 populations after six cycles of exposure to high salinity level were tested for salt tolerance during all growth stage. At harvest stage, seed yield and its components were studied for the comparison. Results showed that there were significant differences between all selected genotypes and local eultivars in their overall sensitivities to soil salinity. All selected genotypes were superior in seed yield and its components at maturity to those of the local cultivars at the two location and years. Clearly, all the selected genotypes exhibited more than twice seed yield/m2 compared with that obtained from local cultivars. The results also indicated that there were differences among selected genotypes in their responses to soil salinity between locations and years, but not significant. Important thing is significant improvement in selected genotypes was achieved in their salt tolerance through six cycles of screening and selection to high salinity level. The conclusion is a strong possibility to improve salt tolerant genotypes of wheat with high salt tolerance through plant breeding programs.