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
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
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.
