INFLUENCE OF POTASSIUM DEFICIENCY ON FLOWER YIELD AND FLAVONOID METABOLISM IN LEAVES OF CHRYSANTHEMUM MORIFOLIUM RAMAT.

The effects of potassium (K) deficiency on primary and secondary metabolism in leaves of Chrysanthemum morifolium Ramat. were investigated in five different stages throughout the growing season of the plant to understand the relationship between potassium and the metabolism of C. morifolium. The results suggested that flavonoids content of K-deficient was related to 4-coumarate coenzyme A ligase (4CL) activity closely through the growth stage. Flavonoid and chlorogenic acid concentrations of K-deficient were lower than that of full K supply control (except flower bud differentiation period and budding stage in upper leaves), and the concentration in upper leaves was higher than that in bottom. The mechanism might be that the net photosynthetic rate was decreased in leaves of K₁, which reduced the carbohydrate synthesized in leaves so that the coumarin concentration, which was the substrate of 4CL activity, decreased and consequently lead to the flavonoid and chlorogenic acid concentration decrease.     

Interactive effects of organic acids in the rhizosphere

Organic acids released into the rhizosphere may perform many beneficial functions to the plant including metal detoxification and enhancement of nutrient acquisition. Typically, these organic acids are studied in isolation; however, roots simultaneously exude a cocktail of organic acids and other substances, and their combined impact on rhizosphere processes may be quite different. It has been hypothesized that some exudates may play secondary roles (e.g. inhibitors of microbial activity, blockage of sorption sites), which might enhance the longevity and nutrient-mobilization capacity of others. Here we investigated how the decomposition, sorption and P-solubilizing effects of citrate, malate and oxalate are affected by the presence of malonate and shikimate. We found that in a range of agricultural soils the decomposition of citrate, malate and oxalate was rapid, but not influenced by the presence of large quantities of shikimate or malonate. This suggests that the individual organic acids are taken up by different transport mechanisms or components of the microbial community. At large concentrations, malonate decreased sorption of citrate, malate and oxalate on the soil, whilst shikimate had little effect. The capacity of citrate, malate and oxalate to desorb P was significantly greater in cocktails containing malonate compared with the single organic acid; no effect was seen with shikimate. We conclude that neither malonate nor shikimate at realistic concentrations will significantly affect the biodegradation of citrate, malate or oxalate in the rhizosphere, and while malonate did enhance P desorption, this effect is additive rather than synergistic. Overall, we found little evidence that malonate and shikimate act as secondary regulators of citrate, malate and oxalate behavior in soil.     

人工培育牛黄对小白鼠离体小肠运动的解痉作用

本文证明培育牛黄对乙酰胆硷与氯化钡所引起的小白鼠离体小肠痉挛有解痉作用。培育牛黄的成份中去氧胆酸具有较强的抗乙酰胆硷与氯化钡作用,其浓度与效应呈直线相关。其成分中的胆酸仅有较弱的抗乙酰胆硷作用,且浓度与效应不呈直线相关,也无抗氯化钡作用。     

Effect of acid rain on sandstone: The Royal Palace and the Riddarholm church,Stockholm

The deterioration of two kinds of sandstone is discussed for two 18:th century buildings in central Stockholm: the Royal Palace, and the Royal Carolean Burial Chapel (Karolinska gravkoret) annexed to the mediaeval Riddarholm church. The facades of calcitic Gotland sandstone show many signs of serious decay, such as gypsum formation, pulverized surface, exfoliation, discolouration, and salt efflorescence. The socles are built of the more resistant quartzitic Roslagen sandstone, displaying some discolouration, cracks, and slight exfoliation. In total about 300 samples have been analysed. The surface concentration of sulphur is highest at ground level and at rain-sheltered positions. Chemical and sulphur isotope data indicate that the stone decay to a large part may be attributed to anthropogenic sources like acid deposition and car traffic.     

L-乳酸在湿木耳保鲜中的抑菌效果研究

[目的]探讨L-乳酸对湿木耳保鲜效果的影响,确定最优保鲜条件。[方法]以经处理的湿木耳在37℃下贮存7 d后细菌总数为试验指标,通过单因素试验,研究保鲜剂种类、L-乳酸浓度、灭菌温度和灭菌时间对湿木耳保鲜效果的影响。以L-乳酸浓度、灭菌温度和灭菌时间3个因素进行正交试验优选保鲜条件。[结果]双乙酸钠、山梨酸钾、L-乳酸3种保鲜剂对湿木耳均具有保鲜作用,其中以L-乳酸的保鲜效果最好,其保鲜效果随其浓度的升高而增强。正交试验表明,影响湿木耳保鲜效果的因素依次为：L-乳酸浓度〉灭菌温度〉灭菌时间;最适保鲜条件为：L-乳酸0.40%、灭菌温度80℃、灭菌时间4 min,此时细菌总数为950 cfu/g。[结论]L-乳酸完全能够对湿木耳进行合格、安全的保鲜。     

杂交改良对麻城黑山羊肌肉化学成分的影响

通过分析麻城黑山羊及杂交后代肌肉的化学成分,旨在探讨杂交改良对麻城黑山羊肌肉品质的影响.选用麻城黑山羊,波尔山羊×麻城黑山羊(简称:波麻F1),波麻F1×波麻F1(波麻F2)3个组,以放牧加补饲的方式饲养,试验结束时每组选取12只屠宰并进行肌肉化学成分分析.结果表明,麻城黑山羊及杂交后代间常规营养成分差异均不显著(P＞...     

水杨酸分光光度法测定水中的NO_3~-

以水杨酸为显色剂,建立分光光度法测定水中NO3-含量的方法。结果表明,NO3-含量的最佳测定条件为：吸收波长410nm,1.0ml浓硫酸,1.0ml20% NaOH溶液,显色时间20min。此条件下,NO3-含量在0.5～8.0mg/L范围内遵循比尔定律。NO3-的最低检出限为0.1mg/L,加标回收率为98.0%～102.0%。     

光叶楮叶蛋白提取工艺优化和氨基酸分析研究

光叶楮叶中粗蛋白含量较高,从丰富的光叶楮资源中提取叶蛋白对于缓解紧缺的蛋白质资源具有积极地作用。利用响应面法(RSM)对光叶楮叶蛋白的提取工艺进行优化。在单因素试验基础上,选取试验因素与水平,根据中心组合(Box-Benhnken)试验设计原理,采用四因素三水平的响应面分析法,依据回归分析确定各工艺条件的影响因素,以叶蛋白提取率为响应值作响应面和等高线。在分析各个因素的显著性和交互作用后,得出叶蛋白提取的最佳工艺条件为:时间1.70h,温度54.15℃,料液比1.00∶31.54,NaCl离子浓度为0.20mol.L-1。在此条件下,叶蛋白提取率的理论值达到36.93%。光叶楮叶蛋白的氨基酸分析结果显示,氨基酸组成种类比较齐全,必需氨基酸含量较高。     

副结核分枝杆菌DNA探针的制备与应用

以溶菌酶、ＳＤＳ、高氯酸钠等处理提取副结核分析杆菌Ｃ２株染色体ＤＮＡ，经限制性内切酶Ｐｓｔ Ｉ消化后，以质粒ｐＢｌｕｅｓｃｒｉｐｔ ＳＫ为载体，通过Ｔ４ＤＮＡ连接酶连接，转入Ｅ。ｃｏｌｉ ＤＨ５ａ受体菌中，构建了副结核菌Ｃ２株的ＤＮＡ基因文库。应用反向杂交试验，从基因文库中筛选出４个重组克隆：ＰＴＰ１２、ＰＴＰ１９、ＰＴＰ３８。对这４个重组克隆进行酶切、电泳分析，结果表明４个插入片段长度分别为：４     

团头鲂幼鱼饲料中α-亚麻酸、亚油酸的适宜含量

在半纯化饲料配方的基础上,分别设计6个α-亚麻酸含量(0.02%、0.55%、1.08%、1.60%、2.13%、2.65%)、6个亚油酸含量(0.86%、1.29%、1.73%、2.16%、2.59%、3.03%),以亚麻籽油、玉米油、棕榈油调节饲料中α-亚麻酸、亚油酸的含量,配制等氮等能(粗蛋白质含量为30.09%,粗脂肪含量为6.87%)的12种半纯化试验饲料,探讨团头鲂幼鱼[初始均重为(59.5±0.5)g]饲料中α-亚麻酸、亚油酸的适宜含量。养殖试验分为α-亚麻酸和亚油酸试验2部分,均设6组,每组4个重复,每个重复20尾,养殖周期为85 d。结果表明:在α-亚麻酸试验中,依据回归方程计算得到,在饲料α-亚麻酸含量分别为1.32%、1.33%时,团头鲂幼鱼具有最大的特定生长率和最小的饲料系数;0.02%组的脏体指数显著低于除1.08%组外的其他各组(P0.05),肥满度、肝体指数各组间无显著差异(P0.05);0.02%组血清总胆固醇、甘油三酯含量显著高于0.55%、1.08%组(P0.05),1.60%组血清高密度脂蛋白含量显著高于0.55%、2.13%组(P0.05),0.02%组血清低密度脂蛋白含量显著高于其他各组(P0.05)。在亚油酸试验中,依据回归方程计算得到,在饲料亚油酸含量分别为2.02%、2.03%时,团头鲂幼鱼具有最大的特定生长率和最小的饲料系数;3.03%组的肝体指数显著低于其他各组(P0.05),肥满度、脏体指数各组间无显著差异(P0.05);1.29%组血清总胆固醇含量显著高于1.73%组(P0.05),0.86%组血清甘油三酯含量显著高于1.73%组(P0.05),1.29%组血清高密度脂蛋白含量显著高于0.86%、3.03%组(P0.05),各组血清低密度脂蛋白含量无显著差异(P0.05)。以特定生长率、饲料系数作为主要评价指标,结合部分血清生化指标和形体指标,得到适合团头鲂幼鱼快速生长、维持鱼体正常健康的饲料中适宜的亚麻酸、亚油酸含量分别为1.32%~1.33%、2.02%~2.03%。