In tropical ecosystems,species with an impermeable seed coat,i.e.physical dormancy(PY),are large in number and their seed coat is considered to be an adaptive trait for species persistence and colonization.However,onl...In tropical ecosystems,species with an impermeable seed coat,i.e.physical dormancy(PY),are large in number and their seed coat is considered to be an adaptive trait for species persistence and colonization.However,only little is known about their mechanisms for breaking dormancy.The objective of this study was to understand the importance of seed maturation site and burial location in determining the PY release of Senna auriculata.Freshly collected seeds of S.auriculata from Vellore and Coimbatore,Tamil Nadu,India,germinated to 11±1.5%and19±2.5%respectively and remaining seeds did not imbibe water,thus had PY.Germination of seeds from both sites following hot-water treatment for 30 s and mechanical scarification increased significantly and seeds were able to germinate at a wide-range of temperatures(5–35℃)both in light and darkness.When incubated at 15/60℃for 3 months,dormancy release for seeds collected from Coimbatore(72%)was greater than seeds matured in Vellore(53%).Following 1 year of burial at three different locations,seeds from Coimbatore germinated to higher percentage than Vellore seeds at all locations.In particular,the higher temperature sites released dormancy to greater extent than the lower temperature site.Our results suggest that summer temperatures(>60℃)prevailing in the tropics provide appropriate cues for breaking PY,but this could be greatly affected by the initial state of seeds and the burial environment.展开更多
To study the effects of Hydroxyapatite(HA) nanoparticles on devitrification in cryoprotectant solutions,the crystallization of glycerol(60%,w/w) and PEG-600(50%,w/w) solutions with HA nanoparticles of different sizes(...To study the effects of Hydroxyapatite(HA) nanoparticles on devitrification in cryoprotectant solutions,the crystallization of glycerol(60%,w/w) and PEG-600(50%,w/w) solutions with HA nanoparticles of different sizes(20 nm、 40 nm、60 nm)and different concentrations(0.1%、 0.5%)during warming were investigated by using differential scanning calorimetry(DSC) combined with cryomicroscopy.Experimental results showed that the presence of nanoparticles does not change the glass transition temperatures and melting temperatures of quenched solutions,but affects the behavior of devitrification and recrystallization upon warming.The morphologies of glycerol and PEG-600 solutions are dendritic and spheric respectively,and the structures are not changed by adding nanoparticles.The ice fraction of glycerol solution containing 0.1%60nm HA nanoparticles diminished significantly when comparing to the control solution.The ice fractions of PEG-600 solutions increased dramatically between-64℃ and-54℃.The findings have significant implications for biomaterial cryopreservation.展开更多
基金supported by Chinese Government Grant Number 2016M601620NSFC(Grant Number31750110474)
文摘In tropical ecosystems,species with an impermeable seed coat,i.e.physical dormancy(PY),are large in number and their seed coat is considered to be an adaptive trait for species persistence and colonization.However,only little is known about their mechanisms for breaking dormancy.The objective of this study was to understand the importance of seed maturation site and burial location in determining the PY release of Senna auriculata.Freshly collected seeds of S.auriculata from Vellore and Coimbatore,Tamil Nadu,India,germinated to 11±1.5%and19±2.5%respectively and remaining seeds did not imbibe water,thus had PY.Germination of seeds from both sites following hot-water treatment for 30 s and mechanical scarification increased significantly and seeds were able to germinate at a wide-range of temperatures(5–35℃)both in light and darkness.When incubated at 15/60℃for 3 months,dormancy release for seeds collected from Coimbatore(72%)was greater than seeds matured in Vellore(53%).Following 1 year of burial at three different locations,seeds from Coimbatore germinated to higher percentage than Vellore seeds at all locations.In particular,the higher temperature sites released dormancy to greater extent than the lower temperature site.Our results suggest that summer temperatures(>60℃)prevailing in the tropics provide appropriate cues for breaking PY,but this could be greatly affected by the initial state of seeds and the burial environment.
基金Natural Science Foundation of China(Grant No.51076108)
文摘To study the effects of Hydroxyapatite(HA) nanoparticles on devitrification in cryoprotectant solutions,the crystallization of glycerol(60%,w/w) and PEG-600(50%,w/w) solutions with HA nanoparticles of different sizes(20 nm、 40 nm、60 nm)and different concentrations(0.1%、 0.5%)during warming were investigated by using differential scanning calorimetry(DSC) combined with cryomicroscopy.Experimental results showed that the presence of nanoparticles does not change the glass transition temperatures and melting temperatures of quenched solutions,but affects the behavior of devitrification and recrystallization upon warming.The morphologies of glycerol and PEG-600 solutions are dendritic and spheric respectively,and the structures are not changed by adding nanoparticles.The ice fraction of glycerol solution containing 0.1%60nm HA nanoparticles diminished significantly when comparing to the control solution.The ice fractions of PEG-600 solutions increased dramatically between-64℃ and-54℃.The findings have significant implications for biomaterial cryopreservation.
