水杨酸对干旱胁迫下桔梗幼苗生理生化指标及相关基因表达的影响

为探讨桔梗对干旱胁迫的应答机制及水杨酸对桔梗抗旱性的影响,以桔梗幼苗为材料,研究外源添加不同浓度水杨酸处理下桔梗幼苗的抗旱性,对桔梗幼苗根和叶片中叶绿素、渗透调节物质、丙二醛含量及抗氧化酶活性进行测定,同时以actin为内参基因,采用实时荧光定量PCR方法检测叶绿素酸酯a氧化酶基因(CAO)、叶绿素合酶基因(CHLG)...     

The impact of foliar fertilizers on growth and biochemical responses of Thymus vulgaris to salinity stress

Salinity reduces plant biomass and may lead to death when severe. To cope with the negative effects of this stress, plant species present specific physiological or biochemical responses. In this work, we hypothesized that spraying salt-stressed thyme leaves with K⁺ and Ca²⁺ could mitigate the negative effects of salinity on plant growth and metabolism. To test this hypothesis, we grew thyme plants under salinity stress for two and four weeks before applying foliar sprays. Also, to test the effect of stress relief, treated plants were allowed two weeks of recovery after four weeks of salt stress. In general, after two and four weeks of salinity stress, the leaf fresh weight of thyme plants was reduced by 31 and 43%, respectively. Salinity also decreased the relative water content, water, and osmotic potentials and led to ion imbalances and nutrient deficiencies. Salinity altered concentration of some essential oils, but leaf antioxidant contents remained fairly stable, except for a significant increase for plants under NaCl?+?KCl two weeks after treatment. Our results indicated that stressed plants accumulated significantly more soluble sugars and amino acids in comparison with the control. Foliar sprays with KCl and CaCl₂ reversed the negative effects of salinity on plant biomass and induced the accumulations of compatible solutes. Moreover, concentrations of some essential oils and gallic acid increased in sprayed plants, but these effects were dependent on the type and duration of the treatment. Overall, spraying leaves with K⁺ and Ca²⁺ was able to mitigate salinity stress in Thymus vulgaris even during the recovery period.     

Intestinal absorption of forsythoside A in different compositions of Shuang-Huang-Lian

Shuang-Huang-Lian (SHL), a traditional Chinese formula containing Lonicerae japonicae flos (LJF), Scutellariae radix (SR) and Forsythiae fructus (FF), is commonly used to treat acute upper respiratory tract infection, acute bronchitis and light pneumonia. Forsythoside A is one of the main active ingredients in Forsythiae fructus, a key herb in SHL. In the present study, effects of different compositions in SHL on the intestinal absorption of forsythoside A were investigated. The observations from in situ intestinal circulation model showed that A/%(h^− 1) of forsythoside A in FF + LSF, FF + SR and SHL were all reduced greatly compared with that in FF. However, in pharmacokinetics study, C_max and AUC_0 → 1440 of forsythoside A all increased and T_1/2 prolonged in SHL, FF + LJF and FF + SR compared with FF. The results indicated that the different compositions of SHL decreased absorption but increased bioavailability of forsythoside A, which may be related to its metabolism inhibited in intestine or liver.     

Determination of Lipid Peroxidation and Fatty Acid Compositions in the Caviars of Rainbow Trout and Carp

In this study, roes obtained from carp (Cyprinus carpio carpio) that were caught in Keban Dam Lake (Turkey) and cultured rainbow trout (Oncorhynchus mykiss) were processed as caviar, and the products were stored at + 4 C°. Lipid peroxidation and the compositions of fatty acids of these products were assessed during production and storage period. The result of fatty analyses showed that palmitic acid (16:0), stearic acid (18:0), palmitoleic acid (16:1), oleic acid (18:1), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), which are all essential fatty acids, were determined in the caviars of the roes obtained from rainbow trout and carp. According to results of chemical analyses, there were no significant differences in thiobarbituric acid reactive substances (TBARs) between rainbow trout and carp caviars (p > 0.05), but malondialdehyde (MDA) levels were found to be statistically significant (p < 0.01). It can be concluded that caviars obtained from both rainbow trout and carp roes are rich in fatty acids and take a part in a balanced and healthy diet.     

等离子体发射光谱法测定蕨麻中人体必需金属元素含量的研究

[目的]为了测定蕨麻中人体必需金属元素的含量,从而为开发蕨麻保健品与饮料提供参考。[方法]采用等离子体发射光谱法测定蕨麻中人体必需金属元素(Ca、Cu、Fe、K、Mg、Mn、Na、Zn)含量。[结果]结果表明,等离子体发射光谱法可同时测定蕨麻中的Ca、Cu、Fe、K、Mg、Mn、Na、Zn等多种金属元素。[结论]该研究为藏药蕨麻的进一步研究开发提供了科学依据。     

乳饮料中苯甲酸、山梨酸、糖精钠的高效液相色谱法测定

本文建立了乳饮料中苯甲酸、山梨酸、糖精钠的高效液相色谱测定方法,该方法样品前处理简单、快速,适合于批量样品测定。方法回收率分别为苯甲酸97.8%、山梨酸98.1%、糖精钠98.7%,变异系数分别为苯甲酸2.2%、山梨酸1.9%、糖精钠1.4%。     

杨桃若干品种及贮藏期间多酚氧化酶活性的变化

[目的]为抑制杨桃贮藏与加工过程中发生的酶促褐变提供理论依据。[方法]以8种酚类物质作底物,采用分光光度计法测定不同杨桃品种果实及其贮藏过程中多酚氧化酶(PPO)活性的变化情况。[结果]5个甜杨桃品种果实中测有PPO活性,该活性均强烈催化焦性没食子酸的氧化反应,但对绿原酸的氧化活性很弱。不同杨桃品种的PPO活性有很大差异,蜜丝甜杨桃PPO对焦性没食子酸的氧化活性明显高于其他品种,而酸杨桃PPO活性极弱。甜杨桃PPO对焦性没食子酸的Km值为3.79~6.80 mmol/L,其Km值因品种不同而异。在果实贮藏期间,3个甜杨桃品种果实中的PPO活性均呈先降再升高而后又降低的变化趋势。[结论]在杨桃制品的加工中宜选用酸杨桃、新加坡红杨桃、马来西亚1号杨桃等PPO活性低的杨桃品种作为加工原料,以有利于酶促褐变的抑制。     

过瘤胃氨基酸在奶牛生产中的应用

本文综述了过瘤胃氨基酸的概念、稳定性、保护效果的测定方法及过瘤胃氨基酸对奶牛生产性能的影响和影响过瘤胃氨基酸效果的因素。     

绿茶和发酵茶的茶多酚组成比较

[目的]比较市售4种绿茶和发酵茶（包括红茶、滇红茶和普洱茶）的茶多酚组成和比例。[方法]采用高效液相色谱法检测茶多酚种类和含量。[结果]市售绿茶均含有没食子儿茶素（GC）、表没食子儿茶素（EGC）和表没食子儿茶素没食子酸酯（EGCG）、表儿茶素（EC）和表儿茶素没食子酸酯（ECG）等茶多酚,以及没食子酸（GA）和咖啡因（CAF）,EGCG为4种绿茶有效成分中的主要物质。半发酵茶铁观音7种有效成分全部检出,EGCG含量最高为16.610 mg/g。发酵茶红茶中茶多酚（儿茶素）部分被降解,GC、EGC、EGCG含量低,咖啡因含量高为17.304 mg/g;滇红茶中EGCG和ECG含量最高,分别为4.588和3.559 mg/g;普洱茶主要有效成分为没食子酸和咖啡因,几乎测不出其他5种茶多酚。[结论]茶叶不同发酵工艺使茶多酚不同程度被降解。     

按不同氨基酸模式配制肉鸭日粮的比较研究

试验比较了不同氨基酸模式对肉鸭生产性能的影响。将320只1日龄的樱桃谷鸭随机分为4组,每组80只,设4个重复,每个重复20只,公母各半,分别饲喂四种日粮(按四种氨基酸模式配制),试验期21天。结果表明:日粮的氨基酸模式为Lys∶Met∶Trp∶Thr=100∶45∶21∶62时,其2周和3周体重高于其它各组,但差异不显著(P>0.05),且F/G和血清尿酸水平最低。