Resistance to toxin-mediated fungal infection: role of lignins,isoflavones, other seed phenolics,sugars, and boron in the mechanism of resistance to charcoal rot disease in soybean

Charcoal rot disease in soybean is caused by the fungus Macrophomina phaseolina, which is believed to infect plants from soil through the roots by a toxin-mediated mechanism. Soybean genotypes exist which are susceptible (S) or moderately resistant (MR) to charcoal rot, but the mechanism of resistance is not known. Significantly (p ≤ 0.05) higher levels of phenolics, seed coat lignin, isoflavones, sugars, and total boron were observed in MR genotype than in S genotype seeds under irrigated and nonirrigated and under experimental M. phaseolina infested and noninfested conditions, indicating a possible association of these substances with resistance to toxin-mediated infection.     

The Performance of Graphene-Enhanced THz Grating: Impact of the Gold Layer Imperfectness

We report the performance of a graphene-enhanced THz grating fabricated by depositing a gold layer on the femtosecond micromachined SiO₂ substrate. The morphology of the gold plated patterned substrate was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while the quality of the chemical vapor deposition (CVD) graphene was evaluated by Raman spectroscopy. The electromagnetic (EM) response of the metasurface comprising the graphene sheet and the gold plated substrate was studied by THz time domain spectroscopy in the 100 GHz–1 THz frequency range. We employed the finite elements method (FEM) to model the metasurface EM response by adjusting the ac conductivity of the gold layer covering the patterned SiO₂ substrate to reproduce the measured transmission/reflection spectra. The results of the numerical simulation reveal the impact of the imperfectness of the gold layer on the performance of the THz metasurface. The experimental results are well described in terms of the Drude–Smith model of metal conductivity that takes into account the anisotropic scattering of the carriers in thin metal films.     

微创去腐技术治疗龋齿临床分析

目的：分析微创去腐技术治疗龋齿的临床效果。方法：搜集2012年3月—2013年3月我院接收的龋齿74例患者,随机分为甲组和乙组。对甲组37例进行微创去腐技术治疗,对乙组37例进行传统治疗。观察、比较甲组和乙组治疗效果。结果：甲组疼痛情况较好,优于乙组;治疗时间短于乙组;填充物完好率高于乙组,复发率低于乙组,预后情况优于乙组,差异显著,有统计学意义（P〈0.05）。结论：微创去腐技术治疗龋齿效果较好,患者疼痛较小,治疗快速,预后良好,值得推广。     

抗人参根腐病生防菌剂的研发与评价

目的:研发安全有效的抗人参根腐病微生物菌剂.方法:平板对峙试验筛选三七内生菌,形态学及分子生物鉴定拮抗菌株,单因素试验优选菌株发酵条件,响应面法优化微生物菌剂的载体及助剂配比制定生产工艺,通过对峙及盆栽试验验证菌剂验证防治效果.结果:平板对峙试验筛选出一株具有显著抗根腐病的菌株Fusarium pseudoanthop...     

草甘膦对党参生长 根腐病及根际土壤微生物的影响

目的 探究除草剂草甘膦对党参生长、根腐病发生和药用成分的影响及可能的土壤微生态机制。方法 调查同一地块中草甘膦处理组和对照组党参的存苗数、鲜质量和发病情况,采用高效液相色谱法（HPLC）测定党参炔苷含量、分光光度法测定多糖含量,采用扩增子技术测定根际土壤微生物群落变化。结果 施用草甘膦能够显著降低党参的存苗数（P<0.05）,对党参地上部生长有一定抑制作用;根腐病发病率及病情指数高于对照组,分别增加了34.51%和34.81%（P<0.05）;党参炔苷和多糖的含量降低。另外,草甘膦处理对党参根际土壤微生物的多样性及真菌群落结构影响较小,但细菌群落中伯克霍尔德氏菌目（Burkholderiales）和鞘脂单胞菌目（Sphingomonadales）显著增加（P<0.05）。结论 施用草甘膦对党参生长有一定抑制作用,导致根腐病加重,这可能与部分根际细菌的相对丰度变化有关。     

广金钱草根腐病病原生物学特性研究

目的:研究温度、pH、培养基、碳源和光照对广金钱草茄病镰刀菌生长、产孢以及孢子萌发的影响。方法:设置不同处理,每处理接3个平板,每项实验重复3次。结果:茄病镰刀菌生长温度范围为12～37℃,最适为20～30℃。茄病镰刀菌在pH3.0～14.0范围内均能生长,最适pH为9.0～11.0。PDA、PSA、OMA和Czapek培养基对茄病镰刀菌生长影响不显著,但对孢子萌发率有较大影响,在Czapek培养液中孢子萌发率最高。不同碳源Czapek培养基上茄病镰刀菌生长和孢子萌发率明显不同,以蔗糖和麦芽糖为碳源的培养基菌落扩展最快,其次是葡萄糖和乳糖,果糖最差,同时以果糖、葡萄糖、麦芽糖和蔗糖为碳源的Czapek培养液孢子萌发最高,而乳糖较低。光照对茄病镰刀菌菌丝生长没有影响,但有利于产孢。     

根腐对三七的皂苷含量影响

目的:对比分析根腐三七与正常三七中总皂苷及R1、Rg1、Rb1三种单体的含量,为根腐三七的质量评价及利用提供依据.方法:同田对比正常三七、根腐三七及不同腐烂程度三七的皂苷含量与单体成分,用HPLC法测定单体皂苷含量,大孔吸附树脂吸附比色法测定总皂苷含量.结果:三七根腐后比正常三七总皂苷含量平均降低了30.88%,R1、Rg1、Rb1三种单体平均含量分别降低了25.53%、11.26%、17.82%.结论:三七的皂苷含量随根部腐烂程度的增加而减少,根部腐烂对R1、Rg1、Rb1三种单体皂苷的比例无显著影响.     

Illumina高通量测序揭示黄连根腐根际土壤真菌群落组成及多样性

目的对黄连根腐病病株及健株根际土壤真菌种群组成、丰富度及多样性进行分析。方法利用Illumina高通量测序技术来分析黄连根腐病病株及健株根际土壤真菌种群组成、丰度和多样性。用Spearman分析土壤理化性质和土壤真菌丰富度前35个属的相关性进行分析。结果高通量测序共获得106 267个有效标签(effective tags),主要分为子囊菌门、接合菌门、担子菌门、球囊菌门、壶菌门和Neocallimastigomycota。健株和病株土样真菌种群多样性差异不显著。病株土样中,子囊菌门、担子菌门和壶菌门的相对丰度显著高于健株土壤;而接合菌门、球囊菌门和Neocallimastigomycota在病株土样的相对丰度则显著低于健株土样。在属水平上,病株土壤中镰刀菌属的相对丰度显著高于健株土样。Spearman分析结果表明,镰刀菌属与pH值和速效磷的含量呈显著正相关,与碱解氮的含量呈显著负相关。结论土壤理化性质的改变与土壤真菌多样性变化相关。     

红景天根腐病的防治研究

对新疆红景天根腐病病因调查表明,低海拔区种植、7~8月高温、土壤湿度大(浇水多)亦是红景天根腐病流行的主要原因之一。中耕时适当扒土使红景天根茎部裸出地面和人工摘除花芽等措施可以减轻根腐病的危害。室内及田间药物防治试验表明:多菌灵、多菌灵 福美双混合剂600倍对红景天根腐病的防治效果显著,分别达到82.12%和85.34%。