Seed dormancy of cultivated rice was largely weakened during the progress of domestication.Correct timing and uniformity of seed germination are important for rapid seedling establishment and highyield production.In t...Seed dormancy of cultivated rice was largely weakened during the progress of domestication.Correct timing and uniformity of seed germination are important for rapid seedling establishment and highyield production.In the present study,we found that the heading-date gene Ghd7 acted as a negative regulator of germination.A mutant of ghd7 showed low sensitivity to exogenous ABA treatment during seed germination.Further investigation revealed reduced accumulation of ABA in mature ghd7 seeds as a consequence of dampened expression of OsNCED genes.Moreover,elevated GA_(3) level was detected in seeds of ghd7 mutant during imbibition course,which was attributed to the induction of genes responsible for the synthesis pathways of bioactive GAs.Thus,Ghd7 inhibits seed germination by increasing the ABA/GA_(3) ratio.Besides revealing pleiotropic effects of Ghd7,our results indicate its role in linking seed germination to growth-phase transition in rice,which would enrich the theoretical basis for future breeding practices.展开更多
Stimulated emission depletion(STED)nanoscopy enables the visualization of subcellular organelles in unprecedented detail.However,reducing the power dependency remains one of the greatest challenges for STED imaging in...Stimulated emission depletion(STED)nanoscopy enables the visualization of subcellular organelles in unprecedented detail.However,reducing the power dependency remains one of the greatest challenges for STED imaging in living cells.Here,we propose a new method,called modulated STED,to reduce the demand for depletion power in STED imaging by modulating the information from the temporal and spatial domains.In this approach,an excitation pulse is followed by a depletion pulse with a longer delay;therefore,the fluorescence decay curve contains both confocal and STED photons in a laser pulse period.With time-resolved detection,we can remove residual diffraction-limited signals pixel by pixel from STED photons by taking the weighted difference of the depleted photons.Finally,fluorescence emission in the periphery of an excitation spot is further inhibited through spatial modulation of fluorescent signals,which replaced the increase of the depletion power in conventional STED.We demonstrate that the modulated STED method can achieve a resolution of<100 nm in both fixed and living cells with a depletion power that is dozens of times lower than that of conventional STED,therefore,it is very suitable for long-term superresolution imaging of living cells.Furthermore,the idea of the method could open up a new avenue to the implementation of other experiments,such as light-sheet imaging,multicolor and three-demensional(3D)super-resolution imaging.展开更多
Vector polarization induced by a change in the scalar phase is far beyond our understanding of the relationship between polarization and phase in classical optics due to the entanglement of the inherent polarized mode...Vector polarization induced by a change in the scalar phase is far beyond our understanding of the relationship between polarization and phase in classical optics due to the entanglement of the inherent polarized modes of light beams.To overcome this limitation,we establish this miraculous relationship by the principle of phase vectorization,which can transform three particular phases into linear,circular and elliptical polarizations.A polarized-spatial light modulator based on the principle of phase vectorization can be achieved using a phase-only spatial light modulator,which not only enables pixel-level polarization manipulation of light beams in a real-time dynamic way but also simultaneously retains complete phase control.This work demonstrates the phase-to-polarization link and reports the creation of a polarized-spatial light modulator,which will transform our view of the natural properties of light beams and pave the way for the era of vector optics.展开更多
基金This work was supported by the National Key Research and Development Program of China(2017YFD0100406)China Postdoctoral Science Foundation(2019M652606).
文摘Seed dormancy of cultivated rice was largely weakened during the progress of domestication.Correct timing and uniformity of seed germination are important for rapid seedling establishment and highyield production.In the present study,we found that the heading-date gene Ghd7 acted as a negative regulator of germination.A mutant of ghd7 showed low sensitivity to exogenous ABA treatment during seed germination.Further investigation revealed reduced accumulation of ABA in mature ghd7 seeds as a consequence of dampened expression of OsNCED genes.Moreover,elevated GA_(3) level was detected in seeds of ghd7 mutant during imbibition course,which was attributed to the induction of genes responsible for the synthesis pathways of bioactive GAs.Thus,Ghd7 inhibits seed germination by increasing the ABA/GA_(3) ratio.Besides revealing pleiotropic effects of Ghd7,our results indicate its role in linking seed germination to growth-phase transition in rice,which would enrich the theoretical basis for future breeding practices.
基金This work has been partially supported by the National Basic Research Program of China(No.2017YFA0700500)the National Natural Science Foundation of China(Nos.61620106016,61835009,62005171,and 61975127)+3 种基金Guangdong Natural Science Foundation(Nos.2019A1515110380 and 2020A1515010679)Shenzhen International Cooperation Project(No.GJHZ20180928161811821)Shenzhen Basic Research Project(No.JCYJ20180305125304883)China Post-doctoral Science Foundation(No.2019M663050).
文摘Stimulated emission depletion(STED)nanoscopy enables the visualization of subcellular organelles in unprecedented detail.However,reducing the power dependency remains one of the greatest challenges for STED imaging in living cells.Here,we propose a new method,called modulated STED,to reduce the demand for depletion power in STED imaging by modulating the information from the temporal and spatial domains.In this approach,an excitation pulse is followed by a depletion pulse with a longer delay;therefore,the fluorescence decay curve contains both confocal and STED photons in a laser pulse period.With time-resolved detection,we can remove residual diffraction-limited signals pixel by pixel from STED photons by taking the weighted difference of the depleted photons.Finally,fluorescence emission in the periphery of an excitation spot is further inhibited through spatial modulation of fluorescent signals,which replaced the increase of the depletion power in conventional STED.We demonstrate that the modulated STED method can achieve a resolution of<100 nm in both fixed and living cells with a depletion power that is dozens of times lower than that of conventional STED,therefore,it is very suitable for long-term superresolution imaging of living cells.Furthermore,the idea of the method could open up a new avenue to the implementation of other experiments,such as light-sheet imaging,multicolor and three-demensional(3D)super-resolution imaging.
基金supported by the National Natural Science Foundation of China(62022059/61525503/61620106016/11804232)National key research and development plan“earth observation and navigation”key special project(2017YFB0503102)the National Key Research and Development Program of China(2018YFC1313803).
文摘Vector polarization induced by a change in the scalar phase is far beyond our understanding of the relationship between polarization and phase in classical optics due to the entanglement of the inherent polarized modes of light beams.To overcome this limitation,we establish this miraculous relationship by the principle of phase vectorization,which can transform three particular phases into linear,circular and elliptical polarizations.A polarized-spatial light modulator based on the principle of phase vectorization can be achieved using a phase-only spatial light modulator,which not only enables pixel-level polarization manipulation of light beams in a real-time dynamic way but also simultaneously retains complete phase control.This work demonstrates the phase-to-polarization link and reports the creation of a polarized-spatial light modulator,which will transform our view of the natural properties of light beams and pave the way for the era of vector optics.
