Drought stress is one of the major constraints to rice （Oryza sativa L.） production and yield stability especially in rainfed ecosystems and is getting worse as the climate changes worldwide. Dongxiang wild rice （D...Drought stress is one of the major constraints to rice （Oryza sativa L.） production and yield stability especially in rainfed ecosystems and is getting worse as the climate changes worldwide. Dongxiang wild rice （DXWR） Oryza rufipogon Griff., contains drought resistant gene. Improving drought resistance of cultivars is crucial to increase and stabilize rice grain yield via transferring resistant gene from species related to rice. In this paper, four upland rice, sixty backcross inbred lines （BILs） derived from BC1F5 of R974//DXWR/R974, and their parents were employed to evaluate drought-resistance at seedling stage in the greenhouse. Nine traits were recorded for assessment of drought resistance, including maximum root length （MRL）, number of roots （NR）, shoot length （SL）, dry root weight （DRW）, fresh root weight （FRW）, root relative water content （RRWC）, leaf relative water content （LRWC）, level for rolling leaf （LRL）, and seedling survivability under repeat drought （SSRD）. Using more than 88% of accumulative contribution resulted from the principal component analysis （PCA）, the nine traits were classified into five independent principal components and the line 1949 showed the highest resistance. Analysis on the stepwise regression equation and correlation demonstrated that MRL, RN, FRW, and RRWC significantly influenced the drought resistance, thus could be used as comprehensive index for drought resistance at the seedling stage. Using the major gene plus polygene mixed inheritance model of quantitative traits, the inheritance of drought-resistance of BIL population at seedling stage was mostly controlled by two independent genes plus polygene. As a result, the DXWR could be precious resources for genetic improvement of drought resistance in cultivated rice.展开更多
Cold stress is one of the major restraints for rice production. Cold tolerance is controlled by complex genetic factor. In this study, a backcross inbred lines （BILs） population derived from an inter-specific cross ...Cold stress is one of the major restraints for rice production. Cold tolerance is controlled by complex genetic factor. In this study, a backcross inbred lines （BILs） population derived from an inter-specific cross （Oryza sativa L.xO. rufipogon Griff.） was used for genetic linkage map construction and quantitative trait locus （QTL） mapping. A linkage map consisting of 153 markers was constructed, spanning 1 596.8 cM with an average distance of 11.32 cM between the adjacent markers. Phenotypic evaluation of the parents and BILs under （6±1）℃ cold stress revealed that the ability of cold tolerance in BILs at early seedling obeyed a skewed normal and continuous distribution. Fifteen QTLs on chromosomes 6, 7, 8, 11, and 12 were identified using survival percent （SP） and non death percent （NDP） as indicators of cold tolerance, which could explain 5.99 to 40.07% of the phenotypic variance, of which the LOD values ranged from 3.04 to 11.32. Four QTLs on chromosomes 3, 5 and 7 were detected using leaf conductivity （LC） and root conductivity （RC） as indicators of cold tolerance, ranging from 19.54 to 33.53% for the phenotypic variance explained and 2.54 to 6.12 for the LOD values. These results suggested that there might be multi major QTLs in O. rufipogon and some useful genes for cold tolerance have been transferred into cultivated rice, which would be helpful for cloning and utilizing the cold tolerance-responsive genes from wild rice.展开更多
The objectives of the present study were to estimate genetic diversity and genetic changes of introgression lines （ILs） which derived from cultivated rice （Oryza sativa L. cv. Xieqingzao B, XB） mating with common ...The objectives of the present study were to estimate genetic diversity and genetic changes of introgression lines （ILs） which derived from cultivated rice （Oryza sativa L. cv. Xieqingzao B, XB） mating with common wild rice （O. rufipogon Griff., CWR）. The genetic data of 239 ILs were based on a total of 131 polymorphic microsatellite （SSR） markers distributed across the 12 chromosomes of rice. On average, these ILs possessed 77.1 and 14.31% homozygous bands from XB and CWR, respectively. Most of the ILs were clustered together with XB individual, which was revealed by principal coordinate analysis （PCA） and the program STRUCTURE analysis. The result from PCA demonstrated that some intermediate genotypes between XB and CWR were also found. Moreover, there were some genomic sequence changes including parental bands elimination and novel bands emergence in the ILs. The average Nei＇s gene diversity （He） was 0.296, which was higher than that of cultivated rice. It suggested that interspecific hybridization and gene introgression could broaden the base of genetic variation and lay an important foundation for rice genetic improvement. These different genotypic ILs would provide a better experimental system for understanding the evolution of rice species and the mechanism of alien gene introgression.展开更多
The phenomenon of stochastic resonance （SR） in an asymmetric mono-stable system subject to two external periodic forces and multiplicative and additive noise is investigated. It is shown that the signal-to-noise rat...The phenomenon of stochastic resonance （SR） in an asymmetric mono-stable system subject to two external periodic forces and multiplicative and additive noise is investigated. It is shown that the signal-to-noise ratio （SNR） for the fundamental and higher harmonics is a non-monotonic function of the intensities of the multiplicative and additive noise, as well as of the system parameter. Moreover, the SNR for the fundamental harmonic decreases with the increase of the system asymmetry, while the SNR for the higher harmonics behaves non-monotonically as the system asymmetry varies.展开更多
The junction temperature of red,green and blue high power light emitting diodes(LEDs)is measured by using the emission peak shift method and the forward voltage method.Both the emission peak shift and the forward volt...The junction temperature of red,green and blue high power light emitting diodes(LEDs)is measured by using the emission peak shift method and the forward voltage method.Both the emission peak shift and the forward voltage decrease show a linear relationship relative to junction temperature.The linear coefficients of the red,green and blue LEDs for the peak shift method and the forward voltage method range from 0.03 to 0.15 nm/℃ and from 1.33 to 3.59 mV/℃,respectively.Compared with the forward voltage method,the peak shift method is almost independent of bias current and sample difference.The variation of the slopes is less than 2%for the peak shift method and larger than 30%for the forward voltage method,when the LEDs are driven by different bias currents.It is indicated that the peak shift method gives better stability than the forward voltage method under different LED working conditions.展开更多
基金supported by the National Natural Science Fundation of China (30960189)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China,the project for Principle Research Topic of Jiangxi Education,China(GJJ08146)+3 种基金the Jiangxi Province Project for Principle Research Leader,China (020007)the Jiangxi Province Inviting Tender Project for Principle ResearchTopic,China (20068)the Natural Science Foundation of Jiangxi Province,China (2009GQN0068)the Youth Foundation of Jiangxi Academy of Agricultural Sciences,China (2010CQN008)
文摘Drought stress is one of the major constraints to rice （Oryza sativa L.） production and yield stability especially in rainfed ecosystems and is getting worse as the climate changes worldwide. Dongxiang wild rice （DXWR） Oryza rufipogon Griff., contains drought resistant gene. Improving drought resistance of cultivars is crucial to increase and stabilize rice grain yield via transferring resistant gene from species related to rice. In this paper, four upland rice, sixty backcross inbred lines （BILs） derived from BC1F5 of R974//DXWR/R974, and their parents were employed to evaluate drought-resistance at seedling stage in the greenhouse. Nine traits were recorded for assessment of drought resistance, including maximum root length （MRL）, number of roots （NR）, shoot length （SL）, dry root weight （DRW）, fresh root weight （FRW）, root relative water content （RRWC）, leaf relative water content （LRWC）, level for rolling leaf （LRL）, and seedling survivability under repeat drought （SSRD）. Using more than 88% of accumulative contribution resulted from the principal component analysis （PCA）, the nine traits were classified into five independent principal components and the line 1949 showed the highest resistance. Analysis on the stepwise regression equation and correlation demonstrated that MRL, RN, FRW, and RRWC significantly influenced the drought resistance, thus could be used as comprehensive index for drought resistance at the seedling stage. Using the major gene plus polygene mixed inheritance model of quantitative traits, the inheritance of drought-resistance of BIL population at seedling stage was mostly controlled by two independent genes plus polygene. As a result, the DXWR could be precious resources for genetic improvement of drought resistance in cultivated rice.
基金partially supported by the National Natural Science Foundation of China (31260255,31360327 and 31360147)the Development Program for Young Scientists of Jiangxi Province,China (20112BCB23007)the Scientific Planning Project of Jiangxi Provincial Education Department,China (GJJ12184 and KJLD12059)
文摘Cold stress is one of the major restraints for rice production. Cold tolerance is controlled by complex genetic factor. In this study, a backcross inbred lines （BILs） population derived from an inter-specific cross （Oryza sativa L.xO. rufipogon Griff.） was used for genetic linkage map construction and quantitative trait locus （QTL） mapping. A linkage map consisting of 153 markers was constructed, spanning 1 596.8 cM with an average distance of 11.32 cM between the adjacent markers. Phenotypic evaluation of the parents and BILs under （6±1）℃ cold stress revealed that the ability of cold tolerance in BILs at early seedling obeyed a skewed normal and continuous distribution. Fifteen QTLs on chromosomes 6, 7, 8, 11, and 12 were identified using survival percent （SP） and non death percent （NDP） as indicators of cold tolerance, which could explain 5.99 to 40.07% of the phenotypic variance, of which the LOD values ranged from 3.04 to 11.32. Four QTLs on chromosomes 3, 5 and 7 were detected using leaf conductivity （LC） and root conductivity （RC） as indicators of cold tolerance, ranging from 19.54 to 33.53% for the phenotypic variance explained and 2.54 to 6.12 for the LOD values. These results suggested that there might be multi major QTLs in O. rufipogon and some useful genes for cold tolerance have been transferred into cultivated rice, which would be helpful for cloning and utilizing the cold tolerance-responsive genes from wild rice.
基金partially supported by the National Natural Science Foundation of China (30860120 and 30900781)the Natural Science Foundation of Jiangxi Province, China(2008GQN0059)the Development Program for Young Scientists of Jiangxi Province, China (20112BCB23007)
文摘The objectives of the present study were to estimate genetic diversity and genetic changes of introgression lines （ILs） which derived from cultivated rice （Oryza sativa L. cv. Xieqingzao B, XB） mating with common wild rice （O. rufipogon Griff., CWR）. The genetic data of 239 ILs were based on a total of 131 polymorphic microsatellite （SSR） markers distributed across the 12 chromosomes of rice. On average, these ILs possessed 77.1 and 14.31% homozygous bands from XB and CWR, respectively. Most of the ILs were clustered together with XB individual, which was revealed by principal coordinate analysis （PCA） and the program STRUCTURE analysis. The result from PCA demonstrated that some intermediate genotypes between XB and CWR were also found. Moreover, there were some genomic sequence changes including parental bands elimination and novel bands emergence in the ILs. The average Nei＇s gene diversity （He） was 0.296, which was higher than that of cultivated rice. It suggested that interspecific hybridization and gene introgression could broaden the base of genetic variation and lay an important foundation for rice genetic improvement. These different genotypic ILs would provide a better experimental system for understanding the evolution of rice species and the mechanism of alien gene introgression.
基金supported by the Doctor Foundation of SWUST of China under Grant No.08ZX7108
文摘The phenomenon of stochastic resonance （SR） in an asymmetric mono-stable system subject to two external periodic forces and multiplicative and additive noise is investigated. It is shown that the signal-to-noise ratio （SNR） for the fundamental and higher harmonics is a non-monotonic function of the intensities of the multiplicative and additive noise, as well as of the system parameter. Moreover, the SNR for the fundamental harmonic decreases with the increase of the system asymmetry, while the SNR for the higher harmonics behaves non-monotonically as the system asymmetry varies.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB925604,2011CB922004the Natural Science Foundation of China(10990103,60906058)+1 种基金Shanghai Committee of Science and Technology(09DJ1400700,11DZ1140900)China Postdoctoral Science Foundation(20110490075).
文摘The junction temperature of red,green and blue high power light emitting diodes(LEDs)is measured by using the emission peak shift method and the forward voltage method.Both the emission peak shift and the forward voltage decrease show a linear relationship relative to junction temperature.The linear coefficients of the red,green and blue LEDs for the peak shift method and the forward voltage method range from 0.03 to 0.15 nm/℃ and from 1.33 to 3.59 mV/℃,respectively.Compared with the forward voltage method,the peak shift method is almost independent of bias current and sample difference.The variation of the slopes is less than 2%for the peak shift method and larger than 30%for the forward voltage method,when the LEDs are driven by different bias currents.It is indicated that the peak shift method gives better stability than the forward voltage method under different LED working conditions.
