The study was undertaken to assess the genetic effect of quantitative trait loci （QTLs） conferring heat tolerance at flowering stage in rice. A population consisting of 279 F2 individuals from the cross between 996,...The study was undertaken to assess the genetic effect of quantitative trait loci （QTLs） conferring heat tolerance at flowering stage in rice. A population consisting of 279 F2 individuals from the cross between 996, a heat tolerant cultivar and 4628, a heat-sensitive cultivar, was analyzed for their segregation pattern of the difference of seed set rate under optimal temperature condition and high temperature condition. The difference of seed set rate under optimal temperature condition and high temperature condition showed normal distribution, indicating the polygenic control over the trait. To identify main effect of QTL for heat tolerance, the parents were surveyed with 200 primer pairs of simple sequence repeats （SSR）. The parental survey revealed 30% polymorphism between parents. In order to detect the main QTL association with heat tolerance, a strategy of combining the DNA pooling from selected segregants and genotyping was adopted. The association of putative markers identified based on DNA pooling from selected segregants was established by single marker analysis （SMA）. The results of SMA revealed that SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The heat tolerance during flowering stage in rice was controlled by multiple gene. The SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The two genetic loci, especially for RM3735 on chromosome 4, can be used in marker-assistant-selected method in heat tolerance breeding in rice.展开更多
The microscopic and ultrastructural characteristics of mesophyll cells in flag leaves of two rice lines （a thermosensitive line 4628 and a thermo-resistant line 996） under high temperature stress （37℃ during 8：00...The microscopic and ultrastructural characteristics of mesophyll cells in flag leaves of two rice lines （a thermosensitive line 4628 and a thermo-resistant line 996） under high temperature stress （37℃ during 8：00-17：00 and 30℃ during 17：00-8：00） were investigated using an optical and a transmission electron microscopy. The membrane permeability and malondialdehyde content increased under the high temperature stress, and the increase of both variables was greater in the line 4628 than in the line 996. Under the high temperature stress, the line 996 showed tightly arranged mesophyll cells in flag leaves, fully developed vascular bundles and some closed stomata, whereas the line 4628 suffered from injury because of undeveloped vascular bundles, loosely arranged mesophyll cells and opened stomata. The mesophyll cells in flag leaves of the line 4628 were severely damaged under the high temperature stress, i.e. the chloroplast envelope became blurred, the grana thylakoid layer was arranged loosely and irregularly, the stroma layer disappeared, many osmiophilic granules appeared within the chloroplast, the outer membrane of mitochondria and the nucleus disintegrated and became blurred, the nucleolus disappeared, and much fibrillar-granular materials appeared within the nucleus. In contrast, the mesophyll cells in flag leaves of the line 996 maintained an intact ultrastructure under the high temperature stress. From these results, it is suggested that the ultrastructural modification of the cell membrane system is the primary plant response to high temperature stress and can be used as an index to evaluate the crop heat tolerance.展开更多
The nonlinear viscoelastic wave equation ｜μt｜^pμtt-△μ-μutt＋∫^t0g（t-s）△μ（s）ds＋｜μ｜^pU=0,in a bounded domain with initial conditions and Dirichlet boundary conditions is consid- ered. We prove that, fo...The nonlinear viscoelastic wave equation ｜μt｜^pμtt-△μ-μutt＋∫^t0g（t-s）△μ（s）ds＋｜μ｜^pU=0,in a bounded domain with initial conditions and Dirichlet boundary conditions is consid- ered. We prove that, for a class of kernels 9 which is singular at zero, the exponential decay rate of the solution energy. The result is obtained by introducing an appropriate Lyapounov functional and using energy method similar to the work of Tatar in 2009. This work improves earlier results.展开更多
In this paper, we consider the following viscoelastic wave equation with delay|u_t|~ρu_(tt)-△u-△u_(tt)+∫_0~t g(t-8)△u(8)d8 + μ_1 u_t(x,t) + μ_2 u_t(x,t-τ) = b|u|^(p-2) u in a bounded domain. Under appropriate ...In this paper, we consider the following viscoelastic wave equation with delay|u_t|~ρu_(tt)-△u-△u_(tt)+∫_0~t g(t-8)△u(8)d8 + μ_1 u_t(x,t) + μ_2 u_t(x,t-τ) = b|u|^(p-2) u in a bounded domain. Under appropriate conditions on μ1, μ2, the kernel function g, the nonlinear source and the initial data, there are solutions that blow up in finite time.展开更多
The in vitro digestibility of alcalase enzymatic hydrolysates of β-conglycinin was studied. The results showed that the zeta potentials of β-conglycinin hydrolysates decreased and their electronegativity increased w...The in vitro digestibility of alcalase enzymatic hydrolysates of β-conglycinin was studied. The results showed that the zeta potentials of β-conglycinin hydrolysates decreased and their electronegativity increased when digested with pepsin and trypsin. Furthermore, the content of peptides with molecular weight from 10 kDa to 20 kDa remained stable, while those with higher molecular weight （〉20 kDa） decreased, and those with lower molecular weight （〈10 kDa） increased. The proportion of highly hydrophobic peptides decreased in the process of the in vitro digestion, but no significant change in the surface hydrophobicity indices of digestion products was observed （P 〈 0.05）. These results indicate that the β-conglycinin hydrolysates were degraded through in vitro digestion, but the degree of degradation was relatively low. Peptides with molecular weight from 10 kDa to 20 kDa in the β-conglycinin hydrolysates resisted the digestion by pepsin and trypsin and they remained stable during the in vitro digestion processes.展开更多
基金supported by the National Natural Science Foundation of China (30500315)Transformation of Agricultural Scientific and Technological Achievements Program from the Ministry of Science and Technology of China (05EFN214300193)Educational Foundation of Hunan Province,China (07C360)
文摘The study was undertaken to assess the genetic effect of quantitative trait loci （QTLs） conferring heat tolerance at flowering stage in rice. A population consisting of 279 F2 individuals from the cross between 996, a heat tolerant cultivar and 4628, a heat-sensitive cultivar, was analyzed for their segregation pattern of the difference of seed set rate under optimal temperature condition and high temperature condition. The difference of seed set rate under optimal temperature condition and high temperature condition showed normal distribution, indicating the polygenic control over the trait. To identify main effect of QTL for heat tolerance, the parents were surveyed with 200 primer pairs of simple sequence repeats （SSR）. The parental survey revealed 30% polymorphism between parents. In order to detect the main QTL association with heat tolerance, a strategy of combining the DNA pooling from selected segregants and genotyping was adopted. The association of putative markers identified based on DNA pooling from selected segregants was established by single marker analysis （SMA）. The results of SMA revealed that SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The heat tolerance during flowering stage in rice was controlled by multiple gene. The SSR markers, RM3735 on chromosome 4 and RM3586 on chromosome 3 showed significant association with heat tolerance respectively, accounted for 17 and 3% of the total variation respectively. The two genetic loci, especially for RM3735 on chromosome 4, can be used in marker-assistant-selected method in heat tolerance breeding in rice.
基金supported by the National Natural Science Foundation of China (Grant No. 30500315)the Agricultural Technological Results Transformation Item of Ministry of Agriculture, China (Grant No. 05EFN214300193)the Educational Foundation of Hunan Province, China (Grant No. 07C360)
文摘The microscopic and ultrastructural characteristics of mesophyll cells in flag leaves of two rice lines （a thermosensitive line 4628 and a thermo-resistant line 996） under high temperature stress （37℃ during 8：00-17：00 and 30℃ during 17：00-8：00） were investigated using an optical and a transmission electron microscopy. The membrane permeability and malondialdehyde content increased under the high temperature stress, and the increase of both variables was greater in the line 4628 than in the line 996. Under the high temperature stress, the line 996 showed tightly arranged mesophyll cells in flag leaves, fully developed vascular bundles and some closed stomata, whereas the line 4628 suffered from injury because of undeveloped vascular bundles, loosely arranged mesophyll cells and opened stomata. The mesophyll cells in flag leaves of the line 4628 were severely damaged under the high temperature stress, i.e. the chloroplast envelope became blurred, the grana thylakoid layer was arranged loosely and irregularly, the stroma layer disappeared, many osmiophilic granules appeared within the chloroplast, the outer membrane of mitochondria and the nucleus disintegrated and became blurred, the nucleolus disappeared, and much fibrillar-granular materials appeared within the nucleus. In contrast, the mesophyll cells in flag leaves of the line 996 maintained an intact ultrastructure under the high temperature stress. From these results, it is suggested that the ultrastructural modification of the cell membrane system is the primary plant response to high temperature stress and can be used as an index to evaluate the crop heat tolerance.
文摘The nonlinear viscoelastic wave equation ｜μt｜^pμtt-△μ-μutt＋∫^t0g（t-s）△μ（s）ds＋｜μ｜^pU=0,in a bounded domain with initial conditions and Dirichlet boundary conditions is consid- ered. We prove that, for a class of kernels 9 which is singular at zero, the exponential decay rate of the solution energy. The result is obtained by introducing an appropriate Lyapounov functional and using energy method similar to the work of Tatar in 2009. This work improves earlier results.
文摘In this paper, we consider the following viscoelastic wave equation with delay|u_t|~ρu_(tt)-△u-△u_(tt)+∫_0~t g(t-8)△u(8)d8 + μ_1 u_t(x,t) + μ_2 u_t(x,t-τ) = b|u|^(p-2) u in a bounded domain. Under appropriate conditions on μ1, μ2, the kernel function g, the nonlinear source and the initial data, there are solutions that blow up in finite time.
基金the financial support from the National Natural Science Foundation of China(No.30972046)the National Key Technologies Research and Development Program(No.2012BAD34B04)
文摘The in vitro digestibility of alcalase enzymatic hydrolysates of β-conglycinin was studied. The results showed that the zeta potentials of β-conglycinin hydrolysates decreased and their electronegativity increased when digested with pepsin and trypsin. Furthermore, the content of peptides with molecular weight from 10 kDa to 20 kDa remained stable, while those with higher molecular weight （〉20 kDa） decreased, and those with lower molecular weight （〈10 kDa） increased. The proportion of highly hydrophobic peptides decreased in the process of the in vitro digestion, but no significant change in the surface hydrophobicity indices of digestion products was observed （P 〈 0.05）. These results indicate that the β-conglycinin hydrolysates were degraded through in vitro digestion, but the degree of degradation was relatively low. Peptides with molecular weight from 10 kDa to 20 kDa in the β-conglycinin hydrolysates resisted the digestion by pepsin and trypsin and they remained stable during the in vitro digestion processes.
