Silicon effects on phenols metabolism of Avicennia marina under cadmium stress

采用水培方式研究硅对重金属镉胁迫下白骨壤幼苗酚类代谢影响,探讨硅对白骨壤耐受重金属胁迫的影响,结果表明,低浓度镉胁迫(Cd 0.5 Mg·l-1)下,随着外源硅的增加,叶片和根系丙二醛含量降低,但SI 50 Mg·l-1处理中各器官总酚含量最高,硅对各器官单宁含量影响不显著;高浓度镉(Cd 5 Mg·l-1)导致白骨壤叶片和根系膜脂过氧化,使得丙二醛含量显著高于对照,外源硅的添加显著降低了白骨壤叶片和根系丙二醛积累,SI 100Mg·l-1显著增加了各器官中总酚含量和单宁含量,根系丙二醛含量与根系总酚含量呈显著负相关,叶片丙二醛含量与叶片单宁含量呈显著负相关,表明硅显著刺激高镉胁迫下白骨壤植物组织中酚类物质代谢,增加根系和叶片的抗氧化性,进而增加白骨壤对镉的耐受性。The effects of silicon on the phenols metabolism in Avicennia marina seedlings were studied under the stress of cadmium by adopting the hydroponic method,and the effects of silicon on the resistance of A.marina seedling to cadmium were further explored.The results showed that under the stress of cadmium of low concentration( Cd 0.5 mg·L-1),the content of malondialdehyde in the leaves and roots decreased with the increase of the exogenous silicon level,and the total phenol content in each organ was the highest at Si 50 mg·L-1,while the effect of silicon on the tannin content in each organ was not significant.The high-concentration cadmium( Cd 5 mg·L-1) led to the membrane lipid peroxidation of the leaves and roots in A.marina,making the content of malondialdehyde significantly higher than that of the control; the addition of the exogenous silicon significantly reduced the accumulation of malondialdehyde in the leaves and roots of A.marina,and Si 100 mg·L-1significantly increased the contents of total phenol and tannin in each organ.Significant negative correlations between the malondialdehyde content and total phenol content in roots and between the malondialdehyde content and tannin content in leaves were found,indicating that silicon significantly stimulated phenolic metabolism in A.marina organs under the stress of high-concentration cadmium,increased the oxidation resistance of the root system and leaves,and thus increased the tolerance of A.marina to cadmium.国家自然科学基金项目(31370516;31170471); 闽南师范大学博士科研启动项目(2006L21432); 闽南师范大学园林植物生长发育与生态配置校级创新团队项目资

第十八届美国理论与应用力学大会总结

1会议概况2018年6月5—9日,第18届美国理论与应用力学大会(18th U.S. National Congress of Theoretical and Applied Mechanics, USNCTAM2018)在美国芝加哥召开.本次大会由美国力学国家委员会和中国力学学会联合主办,旨在探讨和交流近四年世界范围内在理论和应用力学领域的基础研究、创新技术的最新进展,吸引了来自世界各地的近千名专家学

Dynamics of Phenolic Acids Extracted fromKandelia obovata(S.L.)Yong Leaf Litters and Their Allelopathic Effects on Nitzschia closterium

采用生物测试法,以九龙江口的优势藻种新月菱形藻(nITzSCHIA ClOSTErIuM)为受体研究了秋茄[kAndElIA ObOVATA(S.l.)yOng]凋落叶的抑藻作用,并利用高效液相色谱法对其分解过程中的酚酸化感物质进行了分析.通过酚酸对新月菱形藻密度以及生理生化的影响,探讨了秋茄凋落叶对底栖硅藻的化感效应,丰富了安全、有效防治藻类的爆发的理论依据与实践经验,为揭示红树植物与林内微藻间相互关系提供新的科学依据.对新月菱形藻密度测定的研究发现:未分解秋茄凋落叶水提液的抑藻作用存在浓度效应,随着水提液浓度的增加,抑制作用增强;半分解秋茄凋落叶(半分解期T50=42d)水提液对新月菱形藻的生长则无明显影响.高效液相色谱检测结果确定秋茄凋落叶中存在对羟基苯甲酸、香草酸、丁香酸、绿原酸和咖啡酸;随着凋落叶的分解,酚酸的含量下降.标准酚酸物质及混合酸均对新月菱形藻产生化感抑制作用,且随着浓度增大,抑制作用增强.这表明在红树林根际-沉积物-水环境界面上,红树植物凋落物对微藻的繁殖起到了一定的调控作用,而酚酸是其中起重要作用的一类物质.In order to explore the allelopathy of mangrove leaf litters,Nitzschia closterium was used to examine the allelopathy effects of Kandelia obovata(S.L.)Yong leaf litters on algagrowth.The results showed that water extract of undecomposed K.obovataleaf litters significantly inhibited the growth of N.closterium,the inhibition effects increased at higher concentrations of leaf litters.Water extract of half-decomposed(t50=42d)K.obovataleaf litters had no significant effect on the growth of N.closterium.Hydroxybenzoate,vanilloid,clove acid,chlorogenic acid and caffeic acid were determined by high performance liquid chromatography in K.obovata leaf litters,and the concentration of these components decreased with the decomposition of leaf litters.Our data showed that these phenolic substances had significant allelopathy effect on N.closterium.Therefore,mangrove plants controlled the growth of microalgae in the rhizosphere-sediment-water interface,and allelochemicals was an important reason.This study enriched the theory and practical experience in preventing algal outbreaks safely and effectively,providing a new basis for revealing the relationship between mangroves and microalgae.国家自然科学基金(31170471

Effects of Si on the Low Molecular Weight Organic Acid Metabolism of Avicennia marina Under Cd Stress

以红树植物白骨壤为实验材料,通过水培实验,施加不同浓度的SI和Cd,对比研究Cd胁迫下外源SI对白骨壤幼苗低分子质量有机酸代谢的影响,以探讨外源SI对红树植物抗重金属的影响效应和作用机理.结果表明:Cd胁迫显著降低白骨壤幼苗各器官和根系分泌物中低分子质量有机酸含量;SI对有机酸代谢的影响随Cd处理水平不同而不同,在对照(Cd 0Mg/l)和低质量浓度(Cd 0.5Mg/l)处理下,SI对各器官有机酸含量影响不显著或降低其含量,高质量浓度Cd(Cd 5Mg/l)处理下,SI显著增加叶片和茎部有机酸总量,显著增加根系分泌物中柠檬酸含量;白骨壤各器官和根系分泌物有机酸含量两两间显著相关.由此推测SI是白骨壤生长的有益元素,SI缺乏造成的营养胁迫促使植物体内有机酸代谢做出响应;SI促进高质量浓度Cd处理下植物体内的有机酸代谢,对缓解白骨壤Cd毒害效应具有重要意义.Mangrove plants seem to be highly tolerant of high levels of heavy metal pollution.Some researchers have focused on the mechanisms involved in their metal uptake and tolerance.However the important mechanisms involved are still only partially understood.There are higher concentrations of available Si in mangrove sediments.There is increasing evidence that Si has many beneficial effects on mangrove growth and development and can improve heavy metal resistance of mangrove.In order to explore the Si alleviation mechanisms of the toxicity of heavy metal on mangrove,we investigated the effects of Si and Cd on low molecular weight organic acid metabolism of Avicennia marina by pot experiment.The concentration of low molecular weight organic acid in different organs and root exudates were decreased by Cd addition.The effect of Si on low molecular weight organic acid metabolism varied with Cd treatments.Si did not affect or decreased the concentrations of low molecular weight organic acid in different organs and root exudates in 0mg/L and 0.5mg/L Cd treatments.Si increased the total concentrations of low molecular weight organic acid in the stem and leaf and the concentration of citric acid in root exudates under 5mg/L Cd treatments.The correlation analysis showed that there was a significantly positive correlation between the total concentration of low molecular weight organic acid in different organs and root exudates of A.marina.This suggested that Si was beneficial for the healthy growth and development of A.marinaand organic acid metabolism was enhanced by the lack of Si nutrition stress.Si enhanced low molecular weight organic acid metabolism of A.marina under high Cd stress,which may be related to the amelioration by Si of Cd toxicity.国家自然科学基金重点项目(2013CB956504);国家自然科学基金项目(30970527;31170471;31370516

黄芪水提取物对apoe小鼠动脉粥样硬化斑块部位基质金属蛋白酶9表达及斑块形成的影响

目的探讨黄芪水提取物对载脂蛋白E基因敲除(ApoE-/-) 小鼠主动脉粥样硬化斑块部位基质金属蛋白酶-9(MMP-9)表达及斑块形成的影响。 方法将48只8周龄雄性ApoE-/-小鼠给予高脂饮食喂养，小鼠20周龄时根据随机表按照完全随机法分为4组各12只,即对照组、阿托伐他汀组、黄芪水提取物低剂量组及黄芪水提取物高剂量组。对照组给予生理盐水0.2 ml/d，阿托伐他汀组给予阿托伐他汀10 mg·kg~(-1)·d~(-1)，黄芪水提取物低剂量给予黄芪水提取物 1.25 g·kg-1·d-1、黄芪水提取物高剂量给予黄芪水提取物 5 g·kg-1·d-1灌胃。予给药12周末处死各组小鼠。应用ELISA法测定血清氧化低密度脂蛋白（oxLDL）含量；HE染色、油红O染色观察小鼠主动脉粥样斑块内脂质的形成；用免疫荧光、免疫组化染色法检测观察粥样斑块部位巨噬细胞浸润水平及MMP-9表达。 结果黄芪水提取物明显降低ApoE-/-小鼠，其中黄芪水提取物高剂量组血清oxLDL含量明显低于对照组（5.2±6.1）μg/ml比（15.8±5.4）μg/ml，P<0.01；与对照组比较，黄芪水提取物高剂量组ApoE-/-小鼠动脉粥样斑块面积明显减小（17.24%±4.22%比49.87%±9.37%，P<0.01），动脉管壁斑块弥漫程度较轻(P<0.01)。黄芪水提取物高剂量组斑块中Mac3表达低于对照组(P<0.01)；黄芪水提取物高剂量组与对照组主动脉斑块中MMP-9阳性表达面积平均吸光度值(MA)分别为0.0154±0.0014与0.0263±0.0065 (P<0.01）。 结论黄芪水提取物能够抑制ApoE-/-小鼠动脉MMP-9表达，延缓动脉粥样硬化斑块形成。其机制可能是通过降低ApoE-/-小鼠血清oxLDL水平，抑制巨噬细胞的浸润、迁移及分泌MMP-9，从而抑制斑块形成

Importance of hierarchical structures in wetting stability on submersed superhydrophobic surfaces

Submersed superhydrophobic surfaces exhibit great potential for reducing flow resistance in microchannels and drag of submersed bodies. However, the low stability of liquid-air interfaces on those surfaces limits the scope of their application, especially under high liquid pressure. In this paper, we first investigate the wetting states on submersed hydrophobic surfaces with one-level structure under hydrostatic pressure. Different equilibrium states based on free-energy minimization are formulated, and their stabilities are analyzed as well. Then, by comparison with the existing numerical and experimental studies, we confirm that a new metastable state, which happens after depinning of the three-phase contact line (TCL), exists. Finally, we show that a strategy of using hierarchical structures can strengthen the TCL pinning of the liquid-air interface in the metastable state. Therefore, the hierarchical structure on submersed surfaces is important to further improve the stability of superhydrophobicity under high liquid pressure