The ecological effects of eucalypt plantations（EPs） have garnered increasing attention.To understand their effect on soil quality at a landscape scale,and to determine whether soil quality parameters differ due to d...The ecological effects of eucalypt plantations（EPs） have garnered increasing attention.To understand their effect on soil quality at a landscape scale,and to determine whether soil quality parameters differ due to different stand types,we evaluated soil characteristics in twenty-one groups of EPs,Pinus massoniana Lamb.plantations（PMPs） and natural broadleaved forests（NBFs）across Guangdong Province,China.Both the physical characteristics of soil hydrology and the properties of soil nutrients in A and B horizons were determined.Results showed that,compared to NBFs,EPs and PMPs produced a shallower litter layer,reduced canopy density,higher soil bulk density,significantly lower total porosity,non-capillary porosity,total water volume,and hygroscopic water in the A horizon（P〈0.05）.Moreover,total N,available K,and soil organic carbon（SOC） in EPs and PMPs were significantly lower than in NBFs.EPs and PMPs did not differ significantly in N,P or K content,but PMPs had significantly lower SOC and boron in the A horizon than EPs.Low p H and poor capacity to buffer acidification generally occurred in all cover types.Both EPs and PMPs showed a decline in soil properties relative to NBFs,but EPs and PMPs exhibited no significant difference.These results indicate that actions are needed to ameliorate the potential negative effects on soil quality in forestry plantations.展开更多
通过CM825型皮肤水分测试仪和皮肤斑贴试验,研究聚谷氨酸的保湿功效及安全性。结果表明:不同分子量和质量分数的聚谷氨酸在保湿特性上差异较大,其中分子量为1 200 k Da的聚谷氨酸在质量分数为0.1%时,保湿效果最好;受试者涂抹该受试物2和...通过CM825型皮肤水分测试仪和皮肤斑贴试验,研究聚谷氨酸的保湿功效及安全性。结果表明:不同分子量和质量分数的聚谷氨酸在保湿特性上差异较大,其中分子量为1 200 k Da的聚谷氨酸在质量分数为0.1%时,保湿效果最好;受试者涂抹该受试物2和4 h后皮肤水分含量的变化率分别为(103.9±0.2)%和(112.2±0.2)%,接近现在广泛使用的保湿剂透明质酸钠的(114.0±0.3)%;皮肤斑贴试验结果表明聚谷氨酸对皮肤安全、无刺激性。展开更多
基金supported by the Science and Technology Department of Guangdong Province,China(Nos.2015B020207002 and 2014A020216032)the National Natural Science Foundation of China(No.31270675)
文摘The ecological effects of eucalypt plantations（EPs） have garnered increasing attention.To understand their effect on soil quality at a landscape scale,and to determine whether soil quality parameters differ due to different stand types,we evaluated soil characteristics in twenty-one groups of EPs,Pinus massoniana Lamb.plantations（PMPs） and natural broadleaved forests（NBFs）across Guangdong Province,China.Both the physical characteristics of soil hydrology and the properties of soil nutrients in A and B horizons were determined.Results showed that,compared to NBFs,EPs and PMPs produced a shallower litter layer,reduced canopy density,higher soil bulk density,significantly lower total porosity,non-capillary porosity,total water volume,and hygroscopic water in the A horizon（P〈0.05）.Moreover,total N,available K,and soil organic carbon（SOC） in EPs and PMPs were significantly lower than in NBFs.EPs and PMPs did not differ significantly in N,P or K content,but PMPs had significantly lower SOC and boron in the A horizon than EPs.Low p H and poor capacity to buffer acidification generally occurred in all cover types.Both EPs and PMPs showed a decline in soil properties relative to NBFs,but EPs and PMPs exhibited no significant difference.These results indicate that actions are needed to ameliorate the potential negative effects on soil quality in forestry plantations.
文摘利用响应面分析法优化乙醇醇沉提取罗耳阿太菌胞外多糖(Athelia rolfsii exopolysaccharides,AEPS)工艺,并探究其保湿特性及黏度稳定性。以AEPS提取量为指标,在单因素试验的基础上,应用Box-Behnken试验设计优化多糖提取工艺。以壳聚糖和尿素作对照,研究AEPS吸湿及保湿性能,同时研究温度、pH值和离子(Mg2+、Ca2+、Na+、K+)浓度对AEPS黏度稳定性的影响。结果表明:AEPS醇沉最佳条件为浓缩倍数3、醇沉时间17 h、醇沉温度5℃、无水乙醇体积为发酵液的1.7倍,所得AEPS提取量为12.24 g/L;AEPS吸湿及保湿性能明显优于壳聚糖和尿素,1 mg/m L AEPS(黏度57 m Pa·s)保湿性最好;在5~95℃范围内,35℃时AEPS黏度最低,35℃以外多糖黏度都高于51 m Pa·s,但在pH 1~12、离子浓度0~1.0 mol/L范围内,AEPS黏度几乎不受影响。
文摘通过CM825型皮肤水分测试仪和皮肤斑贴试验,研究聚谷氨酸的保湿功效及安全性。结果表明:不同分子量和质量分数的聚谷氨酸在保湿特性上差异较大,其中分子量为1 200 k Da的聚谷氨酸在质量分数为0.1%时,保湿效果最好;受试者涂抹该受试物2和4 h后皮肤水分含量的变化率分别为(103.9±0.2)%和(112.2±0.2)%,接近现在广泛使用的保湿剂透明质酸钠的(114.0±0.3)%;皮肤斑贴试验结果表明聚谷氨酸对皮肤安全、无刺激性。
基金National high technology research and development program(863)(2012AA10A503)National key scientific instrument and equipment development projects(2011YQ080052)Public welfare industry research special(Agriculture)201203026
