荒漠化土地土壤有机质含量的实测光谱估测

在对2个荒漠化典型区土壤采样、化验分析和光谱测量的基础上,分析荒漠化土地土壤的反射光谱特征及土壤有机质的光谱敏感范围,构建多种土壤有机质含量高光谱估测模型。结果表明:荒漠化土地土壤具独特的波浪型光谱曲线,其主要特点是在可见光和近红外的500～900nm光谱范围存在一个明显的弓形突起区,其对提取土壤有机质信息有实际意义;相关分析发现,在中心波长分别为600和830nm的可见光和近红外光光谱范围分别存在1个有机质光谱敏感区;土壤有机质含量高光谱估测模型验证结果表明,利用波长588nm处的反射光谱对数lgR588和反射光谱倒数1/R588以及波长835nm处的反射光谱倒数的导数(1/R835)'和反射光谱对数的导数(lgR835)'分别建立的模型,可以较好地估测荒漠化土地土壤有机质含量。     

大气氟含量与枣黑顶病的相关性

2004年以来,在山西中南部枣(Ziziphus jujuba)区发现一种枣果新病害——枣黑顶病( Prakash,1987;张承林等,1997;张海岚等,1996;刘贤谦等,2009).在枣果近成熟期,其顶部发黑、皱缩,果肉发苦,使枣果失去食用与经济价值,发病率20％～90％,枣农经济损失惨重,出现了大量砍伐枣树的现象,对山西枣产业形成了较大的威胁.为了进一步探索该病的病因及防治方法,笔者于2009年在晋中枣区对枣叶、枣果及大气氟含量进行了测定,并对枣果氟含量与大气氟浓度、距污染源距离及时间的变化等因素进行了相关分析(Divan Junior et al.,2008;Maclean et al.,1976;Seeley,1979;程秋华等,2000;林志红等,2002;赵玲等,2005).     

A new neuroprotective bakkenolide from the rhizome of Peatasites tatewakianus

Constituents of the fruits of Peatasites tatewakianus were investigated. A new compound, namely bakkenolide-VI (1), was isolated. The structures was elucidated on the basis of 1D, 2D NMR, TOF-MS and ESI-MS techniques, and physicochemical properties. The neuroprotective activity of the new compound was assayed with primary cultured neurons exposed to oxygen-glucose deprivation and oxidative insults.     

The screening toolbox of bioactive substances from natural products: a review

Hunting lead compounds from natural products plays a vital role in finding successful drug candidates. The efficiency of screening campaigns is mainly determined by the validity of selected screening models. To screen desired lead compounds, researchers have developed a plethora of experimental screening models. However, the considerable diversity of screening models from animal models, tissue models, to cell models and so on, may cause some trouble in choosing the suitable one. This review provides a toolbox of experimental screening models that have been used to discover new drug candidates from natural products. Two screening indexes are designed for different research directions in this screening toolbox. Index I is proposed from the direction of screening different objective substance populations, including plant extracts, active fractions and pure compounds; index Π is according to screening different drug properties, including pharmacological properties, pharmacokinetic properties and affinity binding properties. We hope that the abbreviated bibliographies will help readers to quickly retrieve useful information by two screening indexes and provide certain reference value for choosing more appropriate screening models. Finally, we discuss ways of improving model systems, as well as future directions.     

九江市林业产权制度改革现状分析与建议

江西省是我国南方重要的集体林区之一,九江市作为江西省的林业大市,其林业在九江社会经济发展中占有重要地位。九江市林权制度改革时间较早,2004年在武宁县开始试点后推开,2007年主体改革结束,并通过江西省林权制度改革领导小组的全面检查验收。笔者通过对九江市林权制度改革现状进行分析,指出林权制度改革中出现的问题,从龙头企业...     

Alteration of glutathione S-transferase properties during the development of <Emphasis Type="Italic">Micromelalopha troglodyta</Emphasis> larvae (Lepidoptera: Notodontidae)

Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.     

聚乙二醇对五硼酸铵改性结构刨花板吸水性能的影响

试验引入聚乙二醇改性体系以补偿五硼酸铵处理结构刨花板时造成物理力学性能的降低,并研究了处理后结构刨花板的吸水性能。结果表明：24h吸水厚度膨胀率和24h吸水率这两项指标与五硼酸铵添加量的相关性最大,该两项结果均随五硼酸铵添加量的增加而增大。聚乙二醇种类对结构刨花板吸水性的影响大于添加量的作用。尤其是24h吸水率,4个添加量水平下的结果均无显著性差异。     

日本水稻核放射性污染现状及去污措施综述

2011年3月日本福岛核电站发生核泄漏事故,释放出大量放射性物质,使周边农田受到直接污染。其中对水稻影响最为严重的放射性核素为放射性铯。分析表明:水稻对铯的吸收是存在差异的,钾肥能有效降低水稻中铯含量,而氮肥会增加其铯含量;距离福岛核电站距离越远其受污染程度越低;土壤中铯的浓度、含钾量、固定铯的能力和耕作表土的厚度都影响着铯的转移;此外,水稻本身的品种也影响着对铯的吸收。水稻去污染的方法包括:利用蓝藻除去表土中放射性铯、对土壤进行深耕及防止水田二次污染等方式来降低土壤本身铯含量;另一方面通过改变土壤粒度分布,向土壤中加入施威特曼石、沸石和蛭石及控制肥料比例等方式来抑制土壤中铯的转移。以上除污染方法的综合应用效果十分显著,福岛县水稻含铯量于2014年已全部低于25 Bq/kg。该研究为中国构建农作物放射性污染特征数据库及相关应急管理提供参考。     

中国主栽青辣椒品种鲜切加工适宜性评价

为科学评价青辣椒品种的鲜切加工适宜性,收集中国主栽青辣椒品种20个,统一种植,在同一成熟度下采收,并对其感官理化指标(L*、a*、b*值、感官评价得分、出品率、果皮硬度、果肉厚度、含水率、糖酸比、可溶性固形物含量、可滴定酸),功能性指标(维生素C含量、总酚含量、DPPH自由基清除能力(DPPH free radical scavenging activity)、铁离子还原能力(Ferric iron reducing antioxidant power)、ABTS自由基清除能力(ABTS radical scavenging activity)、β-胡萝卜素含量进行测定。应用SAS9.2软件对基础数据进行显著性分析;应用相关性、主成分、Varclus变量聚类及因子评价分析对17项指标进行降维处理,筛选核心评价指标;运用层次分析法确定主评价指标权重;运用灰色关联度分析法对20个青辣椒品种的鲜切加工适宜性进行评价。结果表明:显著性分析发现除含水率外,青辣椒的其他指标品种间差异极显著(P0.001),其中b*值、β-胡萝卜素含量及FRAP值的变异系数较大;在所有品种中陇椒5号的维生素C含量在α=0.05水平上显著高于其他品种,京辣2号的β-胡萝卜素含量在α=0.05水平上显著高于其他品种,京研皱皮辣、陇椒5号的抗氧化能力在α=0.05水平上显著高于其他品种。相关性分析发现果皮硬度与感官评价得分呈极显著负相关,相关系数为-0.68,与可溶性固形物含量呈极显著正相关,相关系数为0.72;糖酸比与可滴定酸含量呈极显著负相关,相关系数为-0.81;维生素C含量与FRAP值、ABTS值及总酚含量呈极显著正相关,相关系数分别为0.69、0.73、0.58;果肉厚度与维生素C含量呈显著负相关、与总酚含量呈极显著负相关,相关系数分别为-0.5、-0.6;β-胡萝卜素含量与L*、b*值呈极显著负相关,相关系数分别为-0.63、-0.66。主成分、聚类、因子评价及层次分析确定感官评价得分、维生素C含量、出品率、糖酸比、β-胡萝卜素含量及总酚含量为主要评价因子,权重分别为38.15%、26.55%、18.37%、9.00%、5.00%、2.94%。灰色关联度分析表明针对鲜切加工,微辣的青椒品种中"国福311"和"中椒106"的加工品质较好,中辣青椒品种中"陇椒6号"的加工品质较好,强辣青椒品种中"兴蔬皱皮辣"的加工品质较好。以上研究结果可以为鲜切青辣椒生产加工过程中原料的选择提供科学的数据和方法,同时也可为青辣椒育种如富集功能性成分品种的选育提供指导。     

适宜干燥方法提高干制枸杞品质

为缩短鲜枸杞的干制时间,获得高品质的干制枸杞,该文通过比较自然晾晒、燃煤烘干房以及太阳能干燥设备对枸杞的干燥效率的差异以及测定并分析3种干燥方式获得干果的主要功能性成分（总糖、总黄酮、多糖、甜菜碱,类胡萝卜素）含量及外观品质和出糖率的差异。试验结果表明,采用太阳能干燥设备干燥枸杞的时间最少约为26 h,功能性成分总质量分数约71.71 g/(100 g),与其他2种干燥方式相比功能性成分损失降低,干枸杞色泽更接近鲜枸杞的色泽,出糖率约为1.53%,低于其他2种干燥方式。太阳能干燥设备对于枸杞干燥具有显著的优势,应用前景广阔。