The effect of C-2-carboxyphenyl derivatives of certain heterocyclic compounds on root geotropism in cress seedlings

The effects on root geotropism of 2-carboxyphenyl derivatives of various five- and six-membered heterocyclic compounds have been assessed. In an assay involving cress seedlings, appropriately substituted derivatives of isoxazole, 1,3,4- and 1,2,4- oxadiazoles, 1,3,4-thiadiazole, 1,2,4-triazole, thiazoie, pyridine, pyrimidine and pyridazine were highly effective in eliminating the geotropic response.     

干旱对小麦幼苗Cu、Mn含量的影响及其机理研究

采用液体培养法,研究了不同干旱处理方法,即每天间断干旱1 h2、h、3 h、4 h和连续干旱24 h,对小麦幼苗两种微量元素Cu、Mn的吸收、分布及叶绿素含量的影响。结果表明:间断干旱1 h、2 h处理,小麦幼苗根、茎、叶的Cu、Mn含量及叶绿素含量均有所增加,间断干旱2 h处理增加更显著;间断干旱3 h4、h和连续干旱处理均使小麦幼苗根茎叶中Cu、Mn含量及叶绿素含量降低,连续干旱处理降低最显著。随着干旱程度的增加,小麦幼苗Cu、Mn含量呈"钟型曲线"变化,即先随干旱程度增加而增加,当干旱达到一定程度后随干旱程度增加而减少。小麦幼苗Cu、Mn含量和叶绿素含量变化趋势一致,三者高度相关。说明适度的干旱处理可增加小麦幼苗中Cu、Mn两种微量元素的含量,而过度干旱则导致小麦幼苗中Cu、Mn含量降低。     

The effect on root geotropism of certain ortho-carboxyphenylpropanones

A series of compounds related to 1-(2′-carboxyphenyl)-3-phenylpropane-1,3-dione has been synthesised and their effects on root geotropism assessed using cress and ryegrass seedlings. The more active members have been found to be highly potent, abolishing root geotropism at concentrations as low as 0.01 mg/litre. In this respect they compare favourably with TIBA and NPA. It is suggested that a 2-carboxy-phenyl radical separated by a 3 carbon unit from a second aromatic ring is essential for activity, and that a C-1 oxygen function enhances the effect.     

Design,synthesis and biological activities of new strobilurin derivatives containing substituted pyrazoles

BACKGROUND: Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin analogues with high activity, a series of new strobilurin derivatives containing substituted pyrazoles in the side chain were synthesised and bioassayed. RESULTS: The compounds were identified by ¹H NMR, IR, MS and elemental analysis. Preliminary bioassays indicated that some title compounds exhibited excellent fungicidal activities against Pseudoperonospora cubensis (Burk. & Curt.) Rostovsev and Erysiphe graminis DC f. sp. tritici Marchal, protecting cucumber and wheat at 6.25 and 1.56 mg L^?1 respectively, and showed a moderately high acaricidal activity against Tetranychus cinnabarinus (Boisd.) at 20 mg L^?1. The relationship between structure and biological activity is discussed in terms of effects of the substituent of the pyrazole ring. CONCLUSION: The present work demonstrates that strobilurin analogues with substituted phenylpyrazolylmethoxymethyl side chains can be used as possible lead compounds for further developing novel fungicides and acaricides. Copyright © 2009 Society of Chemical Industry     

Studies on pesticides based on coumarin. III. Synthesis and antifungal activity of substituted 4-methyl-coumarins and related compounds

A series of substituted 4-methylcoumarins was synthesised and the members tested for their toxicity towards mycelial growth of seven phytopathogenic fungi in culture. Rhizoctonia solani, Alternaria alternata and Fusarium solani exhibited maximum sensitivity to these compounds whereas Pythium aphanidermatum, Colletotrichum falcatum, Drechslera oryzae and Macrophomina phaseolina were relatively less sensitive. 6-Ethyl-3-n- propyl-7-hydroxy4-methylcoumarin ( I ) was relatively toxic towards all fungi except C. falcatum, P. aphanidermatum and M. phaseolina. The 6-n-butyl ( III ) and 6-(1, 1, 3, 3-tetramethylbutyl) ( VI ) derivatives were highly toxic to R. solani with EC₅₀, values of lμg ml^?1.     

Uptake and translocation of bleaching herbicidal compounds in radish seedlings

The relationship between the hydrophobicity of certain herbicidal compounds and the bleaching pattern caused on radish cotyledons was investigated. Seed treatment with diphenylpyridones, as well as with established herbicides, produced three types of bleaching pattern according to their hydrophobicity. The less hydrophobic compounds caused complete bleaching of both cotyledons, but the compounds with more hydrophobicity caused only partial bleaching. The critical points for whole or partial bleaching were in the range of log K_ow 4–5 (K_ow: octanol/water partition coefficient), and these values were changed slightly with their chemical classes. Uptake of compounds into the seed coat took place rapidly; these compounds were then translocated slowly from the seed coat to the embryo, namely, radicle, abaxial surface of one cotyledon and marginal areas of both cotyledons. Application of these compounds to roots resulted in initial translocation to marginal areas of both cotyledons, with subsequent translocation to the middle area. It is believed that compounds taken up into the radicle were translocated to both cotyledons in a manner similar to that following application to roots. These effects following uptake by seeds can be used as a translaminal and lateral transport assay for bleaching herbicidal compounds in cotyledons.     

茉莉酸甲酯对水稻白叶枯病的诱导抗性及相关防御酶活性的影响

为探索茉莉酸甲酯(methyl jasmonate,MeJA)诱导水稻抗白叶枯病的效应,采用MeJA喷雾处理剪叶接种法,测定MeJA对水稻幼苗的白叶枯病病情指数、白叶枯病病菌Xanthomonas oryzae pv.oryzae的抑菌效果及对叶片过氧化物酶(peroridase,POD)、过氧化氢酶(catalase,CAT)、超氧化物歧化酶(superoxide dismutase,SOD)、多酚氧化酶(polyphenol oxidase,PPO)和苯丙氨酸解氨酶(phenylalnaine ammonialyase,PAL)等相关防御酶活性的影响.0.05 ～ 2.0 mmol/L的MeJA能降低水稻幼苗白叶枯病的病情指数,但对水稻白叶枯病菌无直接抑菌活性;0.1 mmol/L MeJA的诱导效果最好,处理48h后,感病品种温229和抗病品种嘉早312的诱导效果分别为73.18％和70.43％;0.05 ～2.0mmol/L的MeJA处理水稻叶片中POD、CAT、SOD、PPO和PAL活性呈上升趋势.研究表明MeJA能诱导水稻幼苗对白叶枯病的抗性,且诱导抗性的产生与MeJA提高水稻相关防御酶的活性有关.     

Phytotoxicants from microorganisms and related compounds

Phytotoxic compounds produced by microorganisms are reviewed. Their utilisation as leads to new herbicides is explored in three chemical classes : 2-aminoalk-3-enoic acids, ether derivatives of 3-hydroxycyclobut-3-ene-1,2-diones, and 2-(acylaminooxy)acetic acid derivatives. It is concluded that some bacteria and fungi yield compounds possessing sufficient herbicidal activity to be valuable as herbicides as such, or as leads for chemical optimisation.     

Photodecomposition of natural pyrethrins and related compounds

Present knowledge of the photochemistry of the pyrethrins, and of the alcohols and acids from which they are constituted is summarised.     

取代双吡唑类化合物的合成及杀虫活性

以3-氯苯肼盐酸盐( 1 )和1,1,3,3-四甲氧基丙烷( 2 )为起始原料,经环化、Vilsmeier反应得1-(3-氯苯基)-1H-吡唑-4-甲醛( 4);(4 )与3-三氟甲基苯乙酮( 5 )经Claisen-Schmidt缩合反应得取代芳基烯酮类化合物( 6 ),再与水合肼发生环化反应得3-(3-三氟甲基苯基)-5-(3-氯苯基-1H-吡唑)-4,5-二氢吡唑( 7),其与取代异氰酸酯 作用,制得15个未见文献报道的结构新颖的取代双吡唑类化合物。利用核磁共振氢谱(1H NMR)和质谱(MS)对其结构进行了表征。初步生物活性测定结果表明,在 500 mg/L 质量浓度下,部分化合物对小菜蛾Plutella xylostella的致死率达100%,而对苜蓿蚜Aphis medicaginis、稻褐飞虱Nilaparvata lugens、朱砂叶螨Tetranychus cinnabarinus均无杀虫活性。     

Antifungal activities of mono- and di-SCCl3 substituted compounds: Structure-activity correlations

The mono- and di-N-SCCl₃ substituted derivatives of lactams, cyclic urea, 5,5-diphenylhydantoin and 5-ethyl-5-phenylbarbituric acid were synthesized. Many of these compounds have not been reported previously. The antifungal activities were determined by spore germination method using Stemphylium sarcinaeforme, Monilinia fructicola, Helminthosporium maydis and Alternaria solani. Among the lactam and cyclic urea derivatives studied 1,3-bis(trichloromethylthio)-2-imidazolidinone appears to be the most active compound against S. sarcinaeforme, and has activity slightly below those of the commercial products captan and folpet. Among the diphenylhydantoin and phenobarbital derivatives the mono-SCCl₃ compounds appear to be more potent than the disubstituted compounds in most of the cases examined, but they are not as active as the imidazolidinone derivative. The antifungal activity appears to be highly dependent on the lipophilic character as measured by the 1-octanol/water partition coefficient. Since the bis-SCCl₃ compounds are less potent than the mono-substituted compounds in both of the series of compounds studied, it is evident that the whole molecule rather than any decomposition products of the N-SCCl₃ moiety is responsible for the fungitoxicity.     

The rodenticidal activity of reserpine and related compounds

The spread of warfarin resistant mice in the early 1970s prompted an urgent search for alternative rodenticides suitable for commercial use. The early success of a stupefying compound, chloralose (alphachloralose), directed research in that direction and led ultimately to the adoption of reserpine as a rodenticide. Laboratory and field trials of reserpine, and some of its naturally occurring and synthetic analogues, against mice and rats, are reported here.     

Selective complexometric determination of glyphosate and related compounds

A complexometric method has been developed for the selective determination of glyphosate and related compounds. The method is based upon the different pH-dependence of tridentate and tetradentate ligand-metal complex stabilities. Glyphosate, the tridentate ligand forms a stable copper complex at pH ≥ 8 only, whereas N-carboxymethyl-N-phosphonomethylglycine and N,N-bis(phosphonomethyl)glycine, the tetradentate ligands, form sufficiently stable bismuth complexes even at low pH. The method, therefore, consists of aliquot titrations in basic and acidic media, using metal ion titrant solutions. The first aliquot containing N-(phosphonomethyl)glycine plus N-carboxymethyl-N-phosphonomethylglycine or N,N,-bis(phosphonomethyl)glycine is titrated with bismuth volumetric solution at pH 1.8–2–5 in the presence of methylthymol blue indicator. Quantities of the tetradentate ligands can be calculated from the bismuth consumption. The second aliquot is titrated with copper volumetric solution at pH 8–10, in the presence of murexide indicator. The content of glyphosate can be calculated from the difference between the copper and bismuth consumptions. Efficacy of the method is verified by analyses of standard mixtures and industrial samples.     

壳低聚糖处理对苗期甘蔗抗旱性的影响

采用三种不同分子量(Mw3 000;3 000Mw5 000;5 000Mw10 000)相同浓度(50 mg/L)的壳低聚糖分别叶面喷施苗期甘蔗,并测定土壤相对含水量和甘蔗叶片抗旱性生理指标(水势、脯氨酸含量、可溶性蛋白质),以期了解不同分子量壳低聚糖对甘蔗苗期抵御土壤不同程度水分胁迫的影响。结果表明,壳低聚糖叶面喷施可以延缓干旱胁迫下叶片水势下降,提高叶片脯氨酸含量和可溶性蛋白质含量。壳低聚糖有望成为一种新型的甘蔗抗旱调节剂。     

Effect of acetochlor treatment on Fusarium wilt and sugar content in melon seedlings

Pretreatment of soil with the herbicide acetochlor at 0.1–1g g^–1 significantly decreased incidence of wilt due toFusarium oxysporum f. sp.melonis in melon seedlings. Glucose, fructose and sucrose increased in leaves of inoculated and uninoculated melon plants following acetochlor treatment. The increase in sugar levels in stems and roots was less pronounced. Light intensity affected sugar content and disease incidence. The percentage of diseased plants was significantly higher in untreated plants grown under 165E m^–2 sec^–1 compared to plants grown under 300E m^–2 sec^–1. Lowering light intensity resulted in reduction of levels of total sugars on the third and sixth day after inoculation. Acetochlor had little or no effect on growth rate or sporulation of the pathogen in culture. The colonization rate of diseased plant stems by the pathogen was similar in herbicide-treated and untreated plants, thus excluding the possibility that disease reduction by the herbicide is related to direct fungitoxicity.Contribution from the Agricultural Research Organization. No. 1560-E, 1995 series.     

Effect of temperature on virulence of Rhizoctonia solani on soybean leaves and seedlings

Isolates representing 11 anastomosis groups (AGs) of Rhizoctonia solani from various geographic locations and host plants were tested for virulence on soybean leaves at 15, 20, 25, 30, and 35°C, and on soybean seedlings at 20, 25, and 30°C. Numbers of infection cushions formed on soybean leaves were determined using light microscopy. Isolates of AG-1 IA, AG-1 IB and AG-5 were more virulent on soybean leaves at 20, 25, and 30°C than isolates of AG-1 IC and AG-4. Maximum numbers of infection cushions were formed on soybean leaves by AG-1 (IA, IB, and IC), AG-4, and AG-5 at 25 and 30°C. The other AGs tested did not form infection cushions on soybean leaves although some caused minimal disease severity. Isolates of AG-1 IA formed significantly more infection cushions and caused greater disease severity than AG-1 IB and other isolates at 35°C. Maximum seedling infection, based on per cent area of hypocotyl region covered by lesions occurred at 25 C for AG-1 (IA, IB, and IC) and AG-4. Isolates of AG-5 caused greater seedling infection at 20°C than at 25 and 30°C. The other AGs tested caused only minimal damage to the seedlings. Isolates of AG-4 and AG-5 are not known to cause Rhizoctonia foliar blights of soybean in Louisiana, but their potential to be destructive foliar pathogens is confirmed.     

Insecticidal activity of 3-isoxazolyl methanesulfonates and related compounds

Various methanesulfonates, notably of 3-isoxazolols, exhibit interesting insecticidal activity, especially against Musca domestica and Locusta migratoria. Although the symptoms of poisoning are very similar to those caused by parathion, no correlation between in-vitro inhibition of acetylcholinesterase and insecticidal activity was observed. This is also true for several methanesulfonates of hydroxy-heterocycles and phenols included in this study for comparison.     

氯化钾对干旱胁迫下马铃薯幼苗抗旱性的影响及其机制研究

探究了KCl对干旱胁迫下马铃薯幼苗抗旱性的影响及其机制。研究结果表明：增施KCl（0.70 g·株^-1）显著缓解干旱胁迫下马铃薯幼苗叶片相对含水量和叶绿素含量的降低,抑制叶片MDA含量和相对电导率的升高,相对 提高叶片脯氨酸含量、可溶性糖含量、抗氧化酶（SOD、CAT）活性、净光合速率和水分利用效率;增施KCl还相对提高了马铃薯的株高、基径、单株匍匐茎数量和单株产量,增施氯化钾使干旱胁迫条件下马铃薯植株株高、茎粗、单株匍匐茎数和单株产量分别相对提高6.32%、18.28%、13.75%和29.45%。由此可以认为,在干旱条件下增施氯化钾可通过提高马铃薯幼苗的保水能力,缓解干旱胁迫造成的抗氧化酶活性下降并相对提高渗透调节物质含量,减轻干旱胁迫对光合作用和生长发育的不良影响,从而显著提高马铃薯幼苗的抗旱性。     

多效唑对柠条幼苗构型特征的影响

以1年生柠条(Caragana korshinskii)幼苗为材料,研究了不同浓度多效唑处理对柠条幼苗株高、基径、分枝数、分枝角度等地上部分和根系特征参数等地下部分的影响,分析不同浓度处理之间柠条幼苗构型指标的差异。结果显示:随多效唑处理浓度的增加,柠条幼苗株高增长量显著减少、基茎增长量显著增加;分枝数和分枝角度随处理浓度的增加呈现先增加后降低的趋势,400mg·L~(-1)浓度处理使幼苗根系表面积显著增大,根系分级数和各级根系数量增加,表明施用适宜浓度多效唑能够矮化柠条幼苗,增粗基茎,促进分枝、扩大分枝角度,增大柠条幼苗单位面积地表覆盖;同时,能够拓展地下根系的分布面积,增加各级根系数量;综合考虑,在调控柠条幼苗空间构型方面,适宜的多效唑处理浓度为300~400mg·L~(-1)。