Eremanthus erythropappus(DC.)MacLeish is an important forest species native to the Brazilian savanna biome,an environment with well-defined rainy and dry seasons.Its seeds are desiccation tolerant,non-dormant and disp...Eremanthus erythropappus(DC.)MacLeish is an important forest species native to the Brazilian savanna biome,an environment with well-defined rainy and dry seasons.Its seeds are desiccation tolerant,non-dormant and dispersed at the end of dry season.This exposes them to the first sporadic rains that can trigger germination but the subsequent dry days can compromise survival of the newly germinated seed.This study evaluates if the damages caused by drying of germinating E.erythropappus seeds,at the stage when they have lost desiccation tolerance,are lethal.The percentage of normal seedlings was evaluated when seeds with different imbibition times were dried to their initial water content and then pre-humidified and rehydrated.Desiccation tolerance was fully lost after 0.5 mm of hypocotyl-radicle protrusion(approximately 72 h)when the radicle had root hairs,a possible indicator of sensitivity to desiccation.Disintegration of cell contents and ultrastructural damage to the seeds subjected to drying were observed by electron scanning microscope.Root hairs disappeared after drying,reappearing after pre-humidification,possibly an attempt to increase the surface area of the radicle for water uptake.However,the hypocotylradicle axis became darkened,probably by antioxidant system failure,causing seed death.展开更多
The effect of proportional blend of periwinkle and African star apple seed shell as bio-fillers in flexible polyether foam was studied.Flexible polyether foam samples incorporated with these bio-fillers at varying per...The effect of proportional blend of periwinkle and African star apple seed shell as bio-fillers in flexible polyether foam was studied.Flexible polyether foam samples incorporated with these bio-fillers at varying percentages;10%(S1),20%(S2),30%(S3),40%(S4)and 50%(S5)were produced respectively,while 0%(S0)which had no filler was used as control during the experiment.The mechanical properties of the produced foam samples were determined via density,compression set,indentation hardness,tensile strength and elongation at break tests.The cream time,rise time and height of the foam as parameters for characterising the produced foam samples were determined too.Flammability test was also carried out.The microstructure of the foam samples was analysed as well by using the scanning electron microscope.The results of the experiment showed that the density of the foam samples progressively increased from 19.20(S0)-26.45(S5)as the quantity of the filler increased.The indentation hardness result also showed an increase on addition of the filler.The foam’s loading ability also increased on incorporation of the filler but S3 showed remarkable recovery after compression.The tensile strength and elongation at break of the foam decreased on addition of the filler.The morphological analysis ascertained the effect of the progressive introduction of the filler on the surface morphology of the foam.The flammability of the foam was found to decrease as the filler load increased.Since these fillers are of organic origin,readily available,cheap and eco-friendly,they provide a means of making biodegradable foam,and reducing the flammability of foam.Thus,reducing environmental pollution whilst enhancing the mechanical property of foam.展开更多
为优化莲子多糖的提取工艺,以热水浸提方法,考察浸提温度、浸提时间、液料比三因素对莲子多糖得率的影响,在此基础上,设计响应面法Box-Benhnken中心组合实验,对莲子多糖热水浸提工艺进行优化,得到莲子多糖热水浸提的最佳提取条件:浸提...为优化莲子多糖的提取工艺,以热水浸提方法,考察浸提温度、浸提时间、液料比三因素对莲子多糖得率的影响,在此基础上,设计响应面法Box-Benhnken中心组合实验,对莲子多糖热水浸提工艺进行优化,得到莲子多糖热水浸提的最佳提取条件:浸提温度为83℃、浸提时间为3 h、液料比为30∶1 m L/g,莲子多糖得率为8.13%±0.04%,与理论预测值基本一致(相差百分比小于1%),响应面法能较好地应用在莲子多糖热水浸提工艺中。采用环境扫描电镜观察和分析浸提前后莲子粉末的微观形态,结果显示:经热水浸提,莲子细胞完整性被破坏,粉末呈大小不一的片状,且表面粗糙,呈不规则裂痕及沟壑状纹路,浸提前后莲子粉末微观结构差异明显。可见,所采用的热水浸提工艺能较好地将莲子细胞及细胞壁中可溶性多糖浸提出来。展开更多
基金CNPq(National Council for Scientific and Technological Development).Project number 310225/2015-9
文摘Eremanthus erythropappus(DC.)MacLeish is an important forest species native to the Brazilian savanna biome,an environment with well-defined rainy and dry seasons.Its seeds are desiccation tolerant,non-dormant and dispersed at the end of dry season.This exposes them to the first sporadic rains that can trigger germination but the subsequent dry days can compromise survival of the newly germinated seed.This study evaluates if the damages caused by drying of germinating E.erythropappus seeds,at the stage when they have lost desiccation tolerance,are lethal.The percentage of normal seedlings was evaluated when seeds with different imbibition times were dried to their initial water content and then pre-humidified and rehydrated.Desiccation tolerance was fully lost after 0.5 mm of hypocotyl-radicle protrusion(approximately 72 h)when the radicle had root hairs,a possible indicator of sensitivity to desiccation.Disintegration of cell contents and ultrastructural damage to the seeds subjected to drying were observed by electron scanning microscope.Root hairs disappeared after drying,reappearing after pre-humidification,possibly an attempt to increase the surface area of the radicle for water uptake.However,the hypocotylradicle axis became darkened,probably by antioxidant system failure,causing seed death.
文摘The effect of proportional blend of periwinkle and African star apple seed shell as bio-fillers in flexible polyether foam was studied.Flexible polyether foam samples incorporated with these bio-fillers at varying percentages;10%(S1),20%(S2),30%(S3),40%(S4)and 50%(S5)were produced respectively,while 0%(S0)which had no filler was used as control during the experiment.The mechanical properties of the produced foam samples were determined via density,compression set,indentation hardness,tensile strength and elongation at break tests.The cream time,rise time and height of the foam as parameters for characterising the produced foam samples were determined too.Flammability test was also carried out.The microstructure of the foam samples was analysed as well by using the scanning electron microscope.The results of the experiment showed that the density of the foam samples progressively increased from 19.20(S0)-26.45(S5)as the quantity of the filler increased.The indentation hardness result also showed an increase on addition of the filler.The foam’s loading ability also increased on incorporation of the filler but S3 showed remarkable recovery after compression.The tensile strength and elongation at break of the foam decreased on addition of the filler.The morphological analysis ascertained the effect of the progressive introduction of the filler on the surface morphology of the foam.The flammability of the foam was found to decrease as the filler load increased.Since these fillers are of organic origin,readily available,cheap and eco-friendly,they provide a means of making biodegradable foam,and reducing the flammability of foam.Thus,reducing environmental pollution whilst enhancing the mechanical property of foam.
基金Supported by the National Natural Science Foundation of China(30970177,30600035)Knowledge Innovation Program of Chinese Academy of Sciences(KSCX2-YW-Z-067)+1 种基金LSEB of IBCASNational Science Foundation Grant (ATOL-0629657) to Dr.Ickert-Bond
文摘为优化莲子多糖的提取工艺,以热水浸提方法,考察浸提温度、浸提时间、液料比三因素对莲子多糖得率的影响,在此基础上,设计响应面法Box-Benhnken中心组合实验,对莲子多糖热水浸提工艺进行优化,得到莲子多糖热水浸提的最佳提取条件:浸提温度为83℃、浸提时间为3 h、液料比为30∶1 m L/g,莲子多糖得率为8.13%±0.04%,与理论预测值基本一致(相差百分比小于1%),响应面法能较好地应用在莲子多糖热水浸提工艺中。采用环境扫描电镜观察和分析浸提前后莲子粉末的微观形态,结果显示:经热水浸提,莲子细胞完整性被破坏,粉末呈大小不一的片状,且表面粗糙,呈不规则裂痕及沟壑状纹路,浸提前后莲子粉末微观结构差异明显。可见,所采用的热水浸提工艺能较好地将莲子细胞及细胞壁中可溶性多糖浸提出来。
