This study aimed to induce callus from three sunflower （Helianthus annulus L.） hybrids, namely Anna, Alhaja and Kuds, and to evaluate their callus for salt stress tolerance. Cotyledons and hypocotyl were taken from ...This study aimed to induce callus from three sunflower （Helianthus annulus L.） hybrids, namely Anna, Alhaja and Kuds, and to evaluate their callus for salt stress tolerance. Cotyledons and hypocotyl were taken from seedling of these hybrids and cultured on MS media contained 2,4-D （0,0, 0.5, 1.0, 1.5 and 2.0 mg/L） and kinetin （0.0, 0.5, and 1.0 mg/L）. The cultures incubated at 25 ＋ I^C under light condition （1,000 Lux） for 16 h/day. After 6 weeks observations were taken on the response of cotyledons and hypocotyl to callus induction. The induced callus were cultured on the same MS media that contained appropriate concentrations of 2,4-D and kinetin for callus induction as well as contained various concentration of sodium chloride NaCI （0.0, 0.05, 0.1, 0.15 and 0.2%）. After six weeks callus fresh and dry weights, proline and total carbohydrates concentrations were measured. The results showed significant differences among the hybrids, explants, 2,4-D and kinetin concentration and significant interaction between them in their percentage response for callus induction. The results also revealed that fresh and dry weights were significantly reduced with increased NaCI concentration in the medium, hybrids showed significant differences in their response to salt stress. Proline and total carbohydrate concentration increased in callus as NaCI increased in the media. Significant interaction was showed between hybrids and NaCI concentration in these parameters.展开更多
Objective： To validate the hypothesis that there exists an optimal axial compression stress range to enhance tibial fracture healing.Methods： Rabbits with a surgically induced V-shaped tibial fracture were separated...Objective： To validate the hypothesis that there exists an optimal axial compression stress range to enhance tibial fracture healing.Methods： Rabbits with a surgically induced V-shaped tibial fracture were separated into 2 main groups： the control group （C Group, n=6） without application of any axial compression stress stimulation postoperatively and the stimulation group （ S Group, n=90）. The S Group was further divided into 20 subgroups （S11 to S54） in terms of 5 axial compression stress stimulation levels （112.8 kPa, 289.8kPa, 396.5 kPa, 472.7 kPa, and 602.3 kPa） and 4 experimental endpoints （1, 3, 5 and 8 weeks after operation）. A custom made circular external fixator was used to provide the axial compression stress of the fracture sites. Based on X-ray observation, a fracture healing scoring system was created to evaluate the fracture healing process.Results： At 8 weeks after operation, there existed a ＂⌒-shape＂ relationship between healing score and axial compression stress stimulation level of fracture site. The optimal axial compression stress stimulation ranged from 289.8 kPa to 472.7 kPa, accompanying the best fracture healing, i.e. the fracture line became indistinct or almost disappeared, and a lot of callus jointed the two fracture ends. Meanwhile, at 5 weeks after operation, corresponding to the relatively low healing scores, there was a fracture healing performance similar to that at 8 weeks. Besides, at 1 or 3 weeks after operation, for all the axial compression stress levels （0-602.3 kPa）, no obvious healing effect was found.Conclusions： It is implied from the stated X-ray observation results in this study that the potential optimal axial compression stress stimulation and optimal fracture healing time are available. The axial compression stress level of 289.8-472.7 kPa and fracture healing time of more than 8 weeks jointly comprise the optimal axial compression stress stimulation conditions to enhance tibial fracture healing.展开更多
文摘This study aimed to induce callus from three sunflower （Helianthus annulus L.） hybrids, namely Anna, Alhaja and Kuds, and to evaluate their callus for salt stress tolerance. Cotyledons and hypocotyl were taken from seedling of these hybrids and cultured on MS media contained 2,4-D （0,0, 0.5, 1.0, 1.5 and 2.0 mg/L） and kinetin （0.0, 0.5, and 1.0 mg/L）. The cultures incubated at 25 ＋ I^C under light condition （1,000 Lux） for 16 h/day. After 6 weeks observations were taken on the response of cotyledons and hypocotyl to callus induction. The induced callus were cultured on the same MS media that contained appropriate concentrations of 2,4-D and kinetin for callus induction as well as contained various concentration of sodium chloride NaCI （0.0, 0.05, 0.1, 0.15 and 0.2%）. After six weeks callus fresh and dry weights, proline and total carbohydrates concentrations were measured. The results showed significant differences among the hybrids, explants, 2,4-D and kinetin concentration and significant interaction between them in their percentage response for callus induction. The results also revealed that fresh and dry weights were significantly reduced with increased NaCI concentration in the medium, hybrids showed significant differences in their response to salt stress. Proline and total carbohydrate concentration increased in callus as NaCI increased in the media. Significant interaction was showed between hybrids and NaCI concentration in these parameters.
基金This work was supported by grants from the Chongqing Academician Foundation （No. 1998-93）, the National Natural Science Foundation of China （No. 30122202 and No. 30928005） and the Third Military Medical University Research Foundation （No. 2009 XHG16）,
文摘Objective： To validate the hypothesis that there exists an optimal axial compression stress range to enhance tibial fracture healing.Methods： Rabbits with a surgically induced V-shaped tibial fracture were separated into 2 main groups： the control group （C Group, n=6） without application of any axial compression stress stimulation postoperatively and the stimulation group （ S Group, n=90）. The S Group was further divided into 20 subgroups （S11 to S54） in terms of 5 axial compression stress stimulation levels （112.8 kPa, 289.8kPa, 396.5 kPa, 472.7 kPa, and 602.3 kPa） and 4 experimental endpoints （1, 3, 5 and 8 weeks after operation）. A custom made circular external fixator was used to provide the axial compression stress of the fracture sites. Based on X-ray observation, a fracture healing scoring system was created to evaluate the fracture healing process.Results： At 8 weeks after operation, there existed a ＂⌒-shape＂ relationship between healing score and axial compression stress stimulation level of fracture site. The optimal axial compression stress stimulation ranged from 289.8 kPa to 472.7 kPa, accompanying the best fracture healing, i.e. the fracture line became indistinct or almost disappeared, and a lot of callus jointed the two fracture ends. Meanwhile, at 5 weeks after operation, corresponding to the relatively low healing scores, there was a fracture healing performance similar to that at 8 weeks. Besides, at 1 or 3 weeks after operation, for all the axial compression stress levels （0-602.3 kPa）, no obvious healing effect was found.Conclusions： It is implied from the stated X-ray observation results in this study that the potential optimal axial compression stress stimulation and optimal fracture healing time are available. The axial compression stress level of 289.8-472.7 kPa and fracture healing time of more than 8 weeks jointly comprise the optimal axial compression stress stimulation conditions to enhance tibial fracture healing.
