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1.
用昆虫病原线虫液相培养早期发育指标预测产量的研究 总被引：1，自引：1，他引：0
对液相培养繁殖昆虫病原线虫的早期发育指标与最终产量的相关性进行研究，探讨利用早期发育指标预测最终产量的可能性。试验中采用４项早期发育指标：（１）接种代发育比（培养第４天）；（２）接种代繁殖倍数（培养第９天）；（３）子１代发育比（培养第１３天）；（４）子１代繁殖倍数（培养第１８天）。回归分析结果表明，４项发育指标与最终产量均有显著相关性，可以用作预测最终产量的指标。 相似文献
2.
A continuous in vitro steady-state assay procedure was used to investigate the dependence of trout brain mitochondrial Mg2+-stimulated adenosinetriphosphatase specific activity on temperature and substrate concentration. The inhibition of enzyme activity by DDT was independent of substrate concentration. DDT and several analogs caused increases in the experimental activation energy and frequency factor of the enzyme-catalyzed reaction, which gave rise to a negative temperature coefficient of inhibition. It is suggested that DDT and other highly lipophilic compounds have the potential to allosterically affect membrane-bound enzymes by simply becoming a major lipoid component of the membranes. 相似文献
3.
D. Andújar A. Escolà J. R. Rosell-Polo R. Sanz V. Rueda-Ayala C. Fernández-Quintanilla A. Ribeiro J. Dorado 《Gesunde Pflanzen》2016,68(3):155-162
This study evaluated the capabilities of a LiDAR-based system to characterize poplar trees for biomass production. The precision of the system was assessed by analyzing the relationship between the distance records and biophysical parameters. The terrestrial laser scanner (TLS) system consisted of a 2D time-of-flight LiDAR sensor, a gimbal to dynamically stabilize the sensor and a RTK-GPS to georeference its location and, subsequently, the sensor data. The sensor and its stabilizer were fixed facing downwards, on a metal frame designed for this purpose. Then, it was mounted on an all-terrain vehicle to perform 2D scans in planes perpendicular to the travel direction. Distances between the sensor and the surrounding objects had a high spatial resolution, providing high density 3D point clouds. Results on the reliability of the LiDAR system to estimate plant height showed a significant relationship between the sensor readings and actual poplar height and biomass data. In addition, tree biomass and tree volume were properly estimated in the point cloud. Regression analysis showed significant estimates of 0.79 and 0.89 for biomass and volume, respectively. These results reveal the potential of the LiDAR sensor to estimate both, plant height and plant biomass. This sensor’s capability, added to its relative low cost, fast reaction, and the high number of readings per second consolidate the ideal system for estimating the productivity of biomass in energy crops. 相似文献
4.
驱蚊剂定量构效关系(QSAR)的研究对指导高效新驱蚊剂开发、阐明驱蚊剂的驱避机理有重要意义。以40种酰胺类化合物对埃及伊蚊Aedes aegypti的有效保护时间为驱避活性指标,借助PCLIENT(http:∥w w w.vcclab.org/lab/pclient/start.html)量子化学计算软件获得每个化合物的1 773个初始分子描述符,经二元矩阵重排过滤器、多轮末尾淘汰实施特征非线性筛选后,保留了8个物化意义明确的分子描述符,以支持向量回归SVR建立了高精度的非线性QSAR模型,F=8 465,R2=0.999 6。SVR可解释性体系分析结果表明,保留分子描述符对酰胺类驱蚊剂的驱避活性的非线性关系明显。其中,拓扑极性分子表面积TPSA(Tot)对驱避活性影响最为重要,其值越小,活性越高;负电性对驱避活性有较大影响,其值越大,驱避活性越高。 相似文献
5.
建立了同时测定大豆油中126种农药残留的检测方法。样品经乙腈饱和的正己烷溶解并初次除油后用正己烷饱和的乙腈萃取,于 ?5 ℃、20000 r/min下离心5 min,Captiva EMR-Lipid固相萃取柱净化,乙酸乙酯复溶后采用气相色谱-质谱联用仪 (GC-MS/MS) 多反应监测 (MRM) 模式检测,外标法定量。结果表明:在0.003~0.2 mg/L范围内,126种农药的质量浓度与其对应的峰面积间线性关系良好,R2均大于0.995,在0.005、0.01和0.05 mg/kg 3个添加水平下,126种农药的回收率在60%~119%之间,其中122种农药的RSD低于20%,另外4种农药的RSD低于25%。该方法能够有效除去大豆油中甘油及亲脂性干扰物,方法灵敏度、准确度和精密度均符合农药残留检测的要求,为监测大豆油中农药残留含量、有效防范健康风险提供了一种高效、可靠的分析手段。 相似文献
6.
Fifty six 1,2,3-benzothiadiazoles and related compounds were evaluated as carbaryl synergists against the house fly (Musca domestica). Many of these were excellent synergists, the most active being those containing various combinations of halogen, alkyl, or alkoxy substituents in the 5- and/or 6-positions of the ring.Regression analysis on the data from 14 compounds for which substituents constants were available established that synergistic activity can be satisfactorily described by equations in terms of the hydrophobic bonding constant (π) and the homolytic free radical constant (σ ·).The results with compounds related to the 1,2,3-benzothiadiazoles suggest that synergistic activity is associated primarily with the diazosulfide moiety. 相似文献
7.
Balkrishna R. Gandhe Purnanand Rameshwar Prasad Rajinder K. Danikhel Shankarrao K. Shinde Rajendra K. Srivastava Balwant S. Batra Karumuru M. Rao 《Pest management science》1990,29(4):379-385
Thirty-five dialkyl phenyl phosphates analogous to methyl and ethyl paraoxon were synthesized and their insecticidal activity against house fly (Musca nebulo) determined. Gas chromatographic retention indices (GCRI) at 200°C for all the phosphates were determined on OV-101, DB-1701 and DB-WX fused-silica capillary columns. The retention indices on polar and nonpolar columns (DB-1701 and OV-101, DB-WX and OV-101) considered together were shown to be related to the Hansch hydrophobic constant (II). Multiple regression analysis using the least-square method was carried out to establish the linear relationships between insecticidal activity and GCRI along with the Hammett constant, (σ). The multiple correlation coefficients (r) of various parameters obtained using GCRI were found to be as significant as those obtained using II values. It was found that both hydrophobic and electronic effects made a significant contribution to the insecticidal activity of dialkyl phenyl phosphates. It is concluded that GCRI on two columns can be used directly as an indicator for hydrophobicity in QSAR studies provided that a suitable pair of polar and nonpolar columns is used for this purpose. 相似文献
8.
新型含噻唑和三唑环的亚胺类杀菌剂的QSAR研究 总被引：1，自引：1，他引：0
应用Cerius2软件中的主成分分析法(PCA)和Var.Jarvis-Patrick聚类方法对新型含噻唑和三唑环的亚胺类杂环化合物进行分类,再用遗传函数算法(GFA)和分子力场分析方法(MFA)分别进行了二维/三维定量构效关系研究(QSAR),所建模型都通过了显著性检验,CV-r2均大于 0.910,表明模型都具有良好的预测可靠性。计算研究表明:分子的热力学性质(各种原子类型AlogP描述符)、空间结构状态(Jurs参数和Shadow参数)和电拓扑状态指数(S_aaCH)是影响活性的主要二维因素。三维研究结果表明,分子的静电作用强弱对活性影响较大。最后根据药物分子设计理论设计了一系列亚胺类化合物,并用所建最优二维/三维QSAR模型进行活性预测与相互验证,筛选出活性可能较高的6个化合物。该研究可为高效亚胺类杀菌剂的研制提供理论指导。 相似文献
9.
应用叶绿素荧光技术快速预警乌鲁木齐典型农作物干旱胁迫 总被引：1，自引：0，他引：1
通过叶绿素荧光技术,分析了黄瓜、番茄、茄子、辣椒4种乌鲁木齐典型农作物幼苗在干旱胁迫过程中光系统（PSⅠ、PSⅡ）活性的变化特点,同时分析了土壤含水量和叶绿素荧光参数之间的相关关系。结果表明：在干旱胁迫下,4种农作物幼苗的光系统活力受到土壤水分含量变化的影响。Fv/Fm、Y(II)（实际量子产量）随土壤水分含量降低逐渐受到抑制,在土壤失水严重时显著降低。Y(NO)（非调节性能量耗散的量子产量）在干旱胁迫过程中逐渐增加。PSⅡ反应中心潜在活性Fv/F0在指示干旱胁迫危害和鉴别不同植物耐旱性时具有一定优势。通过土壤含水量和叶绿素荧光参数的相关分析发现,土壤含水量与Fv/Fm、Fv/F0、Y(II)和Y(ND)（非光化学能量耗散的量子产量）等呈显著正相关关系,与Y(NO)和Y(I)呈显著负相关关系。叶绿素荧光参数可以反映植株在干旱胁迫下的生理状态,也可以作为土壤水分含量的指示物,对农作物幼苗的干旱胁迫程度做出快速预警。同时,通过干旱胁迫下叶绿素荧光参数的对比,还发现幼苗之间的耐旱性差异,茄子抗旱能力优于其他3种农作物幼苗,黄瓜和番茄幼苗耐旱能力相似,辣椒的耐旱性比其他3种农作物幼苗差。 相似文献
10.
马唐生防菌画眉草弯孢霉毒素α,-βdehydro-curvularin对马唐叶绿体功能的影响 总被引：4，自引：0，他引：4
马唐(Digitaria sanguinalis (L.) Scop.)生防菌画眉草弯孢霉(Curvularia eragrostidis)菌株QZ2000产生一种具有除草剂活性毒素α,β-dehydrocurvularin。通过研究该毒素对马唐类囊体膜光合活性的影响,发现毒素对马唐类囊体膜希尔反应活性、非环式光合磷酸化活性、Mg2+-ATP酶活性和Ca2+-ATP酶活性均有较强的抑制作用,并且Mg2+-ATP酶较Ca2+-ATP酶对毒素更为敏感,但毒素不抑制环式光合磷酸化活性。毒素对马唐叶片叶绿素含量影响较小。从试验结果还可看出,非环式光合磷酸化与希尔反应活性及ATP酶活性呈明显的正相关。上述结果表明,该毒素影响马唐叶绿体的功能。另外,根据我们的试验结果及文献报道,该毒素还具有抗菌活性和杀线虫活性,推测叶绿体可能不是该毒素的惟一作用位点。 相似文献
11.
Gerhard Hamprecht Horst Mayer Karl-Otto Westphalen Helmut Walter 《Pest management science》1999,55(5):566-570
New pyrimidine and triazine intermediates for herbicidal sulfonylureas are prepared as follows: 2,4-dichloro-6-methylpyrimidine is converted via a halogenation, halogen exchange and substitution sequence to 2-amino-4-trifluoromethyl-6-trifluoromethoxypyrimidine. New fluoromethyl-triazines are available starting from guanidine, trichloroacetonitrile and difluoroacetic anhydride, or alternatively from thiocarbamoyl guanidine and chlorodifluoroacetic ester ring closure. To obtain new o-fluoroalkyl-benzenesulfonamide precursors, o-chlorobenzaldehyde was fluorinated with sulfur tetrafluoride, or a bromobenzene derivative was subjected to a substitution reaction with sodium pentafluoropropionate. Sulfonylureas derived from trifluoromethylpyrimidines with an m-methylthio substituent are selective post-emergence herbicides in cotton, presumably due to sulfone metabolization. Selectivity in wheat is obtained by combining 4-methoxy-6-trifluoromethylpyrimidine with a lipophilic difluoromethyl-benzenesulfonamide moiety. Also in the difluoromethyl-triazine series, the combination with the difluoromethyl-benzenesulfonamide moiety is a good choice for wheat selectivity. Chlorodifluoromethyl- and trifluoromethyltriazines, however, combine better with an aromatic ester for best activity and selectivity in wheat. Selected compounds are undergoing broad field tests in wheat. 相似文献
12.
For the purpose of better understanding the molecular mechanism of action of sulfonylurea and sulfonamide herbicides, the quantitative relationship between their structure and herbicidal activity against rape, Brassica campestris L, was analysed using physicochemical parameters and regression analysis and comparative molecular field analysis (CoMFA). The results showed that the structure–activity relationships of the two sets of compounds were identical, which suggested that the two different sets of compounds affect a common region of the receptor site. The CoMFA results were consistent with those derived from traditional QSAR analysis. Combining the traditional QSAR analysis with the CoMFA results, we can conclude that the variations in the herbicidal activity of the two sets of ALS inhibitors were governed dominantly by the three-dimensional steric and electrostatic field parameters of molecules participating in the interaction with the receptor site and there is apparently an optimum electronic property (Σσ or pKa) for the molecules to fit the receptor. © 1999 Society of Chemical Industry 相似文献
13.
在室内测定了樟树(Cinnamomum camphora L.)天然产物莰酮-[2](Cam-phor C10H16O)的杀虫活性和作用方式，并进行了田间试验。结果表明，莰酮对天牛成虫有较强的驱避、熏蒸和触杀作用。每点投放2％莰酮DP1-2g，药后24h对天牛驱避效果为55．00％-85．00％，药后72h达到94．12％-100．00％；熏蒸致死中浓度为8．20mg/L，触杀致死中浓度为15．25mg／L。经回归和相关分析，处理浓度与作用效果相关性均达到极显著水平。每洞穴喷2％莰酮DP0．1-0．2g，对天牛幼虫防治效果达85．80％-100％；每袋装2％莰酮DP1．5-2．5g，药后7-15天对天牛成虫驱避效果为80．95％-100％。药后30-60天为68．29％-86．36％，田间防治效果显著。 相似文献
14.
A radiolabelling method is generally used to determine the foliar uptake of xenobiotics. This technique cannot provide any information on the localization of chemicals inside leaf tissues. The influence of an alcohol ethoxylate surfactant on the uptake of three fluorescent dyes, difluorofluorescein (hydrophilic), rhodamine B (moderately lipophilic) and a naphthalimide dye (lipophilic), into the leaves of three contrasting species, bean (Vicia faba), wheat (Triticum aestivum) and cabbage (Brassica oleracea), at 16 h after treatment was measured using a conventional wash‐off method and also visualized in vivo by confocal laser scanning microscopy (CLSM). Whereas the lipophilic dyes showed greater intrinsic uptake than the hydrophilic one, the enhancing effect of the surfactant on uptake was more pronounced for the latter. CLSM revealed that the presence of the surfactant increased the transport of difluorofluorescein into the epidermal cells of bean and wheat leaves, but not cabbage leaves. Rhodamine B showed greatest transcuticular diffusion in all three species, but most of the dye moved into the vacuole of the epidermal cells. The naphthalimide dye was strongly retained by the wax–cuticle layer of all species, even in the presence of the surfactant. CLSM has proven to be an attractive tool for studying xenobiotic diffusion. The results obtained using fluorescent dyes are believed to be applicable to the foliar uptake of herbicides. 相似文献
15.
Partial cohesive interaction parameters as predictors of the spreading of spray mixtures were investigated. Multiple linear regression of the inverse of the area of spread, 1/A, for leaf surfaces on the partial cohesive interaction parameters of pure liquids gave a good fit (r2 > 0–90) on virtually all tested surfaces. The coefficients obtained from the regression analysis could be used to describe the spreading properties of each surface uniquely. Regression of 1/Afor an unknown liquid on the coefficients of known surfaces could, conversely, be used to obtain the cohesive interaction parameters of the unknown liquid. A linear relationship was observed between the calculated energy of adsorption and the inverse of the area of spread. An increase in molar volume caused a decrease in the slope of the regression line and an increase in roughness caused a similar, but more pronounced, decrease. 相似文献
16.
具有异喹啉-1(2H)-酮骨架的天然产物分布广泛且有丰富多样的生物活性,为进一步明确该类化合物的农用抑菌活性,本文利用Castagnoli-Cushman反应及酯化反应合成了22个具有该骨架的四氢异喹啉酮-4-羧酸(酯) 类化合物。离体抑菌活性测定结果表明,在100 μg/mL下, 5a ~ 5k和6a ~ 6f 对油菜菌核病菌菌丝生长抑制率高于80%,其中 5k 活性最高,EC50值为5.8 μg/mL,但低于对照药剂啶酰菌胺(EC50 = 0.094 μg/mL)。初步构效关系分析表明,在N上引入苯基要优于烷基,苯基上引入不同取代基后抑菌活性均有所提高且表现出位置和数目的选择性;C3位苯基和C4位羧基引入取代基对活性不利。室内离体叶片法结果表明,在500 μg/mL下, 5k 的保护作用防治效果为94.6%,与啶酰菌胺在10 μg/mL下的防治效果(95.8%) 相当。本研究可为该类化合物的进一步结构优化提供借鉴。 相似文献
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18.
为研究内蒙古典型草原不同放牧强度植被反射光谱与植被参数和蝗虫密度的关系,使用地物波谱仪于2015年和2016年对5个放牧梯度,共20hm~2样地进行调查研究。结果表明,不同放牧强度植被地上总生物量与归一化植被指数(NDVI)关系为y=0.034 8+0.002 9x(R~2=0.645 5,P=0.000 2),蝗虫密度与NDVI线性关系为y=0.067+0.013x(R~2=0.415,P=0.006)。对其进行冗余分析(RDA)发现,植被地上总生物量、植物高度、糙隐子草生物量是蝗虫数量和NDVI变化的主要影响因子,其中植被地上总生物量是显著性影响因子(P=0.001)。在不同放牧强度下蝗虫密度与草地NDVI显著相关(P0.05),随NDVI增大而增多。本文研究结果为进一步开展放牧区蝗灾遥感监测和科学合理地利用草地资源奠定了基础。 相似文献
19.
Structure-activity relationships were used to determine the physicochemical properties of DDT that are important in the inhibition of oligomycin-sensitive mitochondrial ATPase activity of red coxal muscle tissue homogenates of the American cockroach (Periplaneta americana). The results were compared with structure-activity relationships derived from toxicity values for houseflies (Musca domestica) and blowflies (Phormia regina), reported in the literature. Toxicity was found to be promoted by hydrophobicity and electron donation. Toxicity was concluded to be a route of action process involving the distribution and partitioning of insecticide to active sites and apart from them. Enzyme inhibition, in contrast to factors contributing to toxicity, was determined to be a mode of action process predicted by the lipophilic parameter (π) and the steric constant, van der Waals radii (VWR), and represents action upon a sterically sensitive, hydrophobic site in the membrane sector of mitochondrial ATPase. 相似文献