Inhibition of radish germination and root growth by coumarin and phenylpropanoids

Thirteen natural and synthetic phenylpropanoids as well as coumarin (2×10⁴M) were tested for their biological activity on radish germination and subsequent root growth in light and darkness. Coumarin was the most potent inhibitor. With some exceptions, phenylpropanoids with a carboxylic group in the side chain inhibited root growth. Coumarin was formed spontaneously by photooxidation of 2-hydroxycinnamic acid. Microscopic observations of root treated with coumarin suggest that this substance inhibits the elongation of cells of the differentiating zone of the root.     

Relationships between chemical structure and inhibitory activity of C6 through C9 volatiles emitted by plant residues

Leaf, stem, flower, fruit, and root residues of a wide variety of plants have been reported to emit bioactiven-alkanes, 2-alkanols,n-alkanals, 2-alkenals, 2-alkanones, andn-alkanoic acids containing from six to nine carbon atoms. During a 72-hr exposure to the vapor phase of these compounds (6.9, 20.8 or 34.4 M/liter), germination of onion, carrot, and tomato seeds was inhibited to varying degrees. The extent of inhibition caused by these plant residue volatiles depended upon the compound type and concentration, carbon-chain length, and the seed species tested. Tomato seeds recovered more fully from exposure to these volatile inhibitors than did those of carrot and onion. Degree of recovery in all three species depended on the type and concentration of volatile present. The C₇ and C₈ compounds were the most inhibitory among these 24 volatiles. Of the six classes of chemicals examined, the 2-alkenals were the most inhibitory, followed by the 2-alkanols,n-alkanals, and 2-alkanones, which were equally effective as seed germination inhibitors. The straight-chain alkanes and alkanoic acids were relatively noninhibitory. Tests of a C₇ and C₉ alkadienal indicated that the C₇ compound was the more inhibitory.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture.     

Metabolism and excretion of the furanocoumarin xanthotoxin by parsnip webworm,Depressaria pastinacella

The parsnip webworm,Depressaria pastinacella, feeds on plants containing high concentrations of furanocoumarins. compounds toxic to many organisms. Parsnip webworm larvae were fed radiolabeled xanthotoxin to quantify the detoxification of this furanocoumarin. They metabolized approximately 95% of the ingested xanthotoxin, indicating that metabolic detoxification is important in their tolerance to this allelochemical. Excretion of xanthotoxin and its metabolites was not restricted to the frass but also occurred by means of the silk glands. The silk glands contained half as much of the tritiated compounds as the rest of the body. Because of the feeding habits of this insect, such an excretory pathway may have implications for interactions with predators and pathogens.     

Juglone reduces growth,nitrogenase activity,and root respiration of actinorhizal black alder seedlings

European black alder trees [Alnus glutinosa (L.) Gaertn.] fix nitrogen with nodular symbionts and are interplanted with valuable black walnut trees (Juglans nigra L.) to increase soil nitrogen fertility. However, on some soils interplanted alder can be killed by black walnut's allelochemical juglone. In order to better understand the effects of juglone directly on the growth, nitrogen fixation, and root respiration of black alder, we grew nodulated alders hydroponically in a nitrogen-free nutrient solution at juglone levels of 2 × 10^–6, 2 × 10^–5, and 0 molar (M). Results indicate that nitrogenase activity (acetylene reduction) of alders growing in 2 × 10^–3 M juglone was reduced relative to alders without added juglone after one day, and in 2 × 10^–6 M juglone after five days. Root respiration (CO₂ evolution) and the relative increase of plant fresh weight were reduced in the 2 × 10^–5 M juglone treatment. In a related experiment, black alder germinants were grown in Flanagan silt loam soil dosed with 10^–3, 10^–4, and 0 M juglone. The inhibitory effects of 10^–3 M juglone on radicle elongation ceased 22–37 days after juglone treatments were started, suggesting that this soil can readily detoxify juglone.     

In vitro metabolism of a linear furanocoumarin (8-methoxypsoralen,xanthotoxin) by mixed-function oxidases of larvae of black swallowtail butterfly and fall armyworm

Studies were made of the comparative in vitro metabolism of [¹⁴C]xanthotoxin and [¹⁴C]aldrin by homogenate preparations of midguts and bodies (carcass minus digestive tract and head) of last-stage larvae of the black swallowtail butterfly (Papilio polyxenes Fabr.) and the fall armyworm [Spodoptera frugiperda (J. E. Smith)]. The two substrates were metabolized by 10,000g supernatant microsomal preparations from both species. Evidence gained through the use of a specific inhibitor and cofactor indicated that mixed-function microsomal oxidases were major factors in the metabolism and that the specific activity of this enzyme system was considerably higher in midgut preparations fromP. polyxenes than in similar preparations fromS. frugiperda. Aldrin was metabolized 3–4 times faster byP. polyxenes, and xanthotoxin 6–6.5 times faster.     

Effect of phytotoxic resin glycoside on activity of H+-ATPase from plasma membrane

A resin glycoside mixture isolated fromIpomoea tricolor inhibited radicle growth ofEchinochloa crusgalli. The effect of the resin was tested on the activity of the plasma membrane H⁺-ATPase fromE. crusgalli. For this purpose, plasma membrane vesicles were purified by the method of aqueous two-phase partitioning. The resin glycoside inhibited by 30% the activity of the plasma membrane ATPase. The same result was obtained with the purified main component of the resin. This indicates that the plasma membrane ATPase can be one of the cellular targets of the resin. Hence it is possible that the mechanism of action of the resin involves an inhibition of the plasma membrane ATPase.     

Effect of diacetyl piquerol on H+-ATPase activity of microsomes fromIpomoea purpurea

The effect of an allelopathic compound, diacetyl-piquerol on the H⁺ -ATPase activity of the microsomal fraction from the radicles of a common weedIpomoea purpurea was studied. The diacetyl-piquerol inhibited the germination and radicle growth fromI. purpurea; the radicle growth was increasingly inhibited (10% to 100%) as piquerol concentrations were raised (10 M to 1000 M). The H⁺-ATPase activity was inhibited (48%) by 500 M diacetyl-piquerol, and this inhibition was higher in plasma membrane ATPase (67.2%) than in tonoplast membrane ATPase (31.4%). Additional studies of the precise physiological mechanisms of interference caused by allelopathic compounds are needed.This study was sponsored by Project PCECCCNA-050954 of Consejo Nacional de Ciencia y Tecnología (CONACyT).     

Analysis,isolation and insecticidal activity of linear furanocoumarins and other coumarin derivatives fromPeucedanum (Apiaceae: Apioideae)

Peucedanum arenarium Waldst. & Kit.,P. austriacum (Jacq.) Koch,P. coriaceum Reichenb.,P. longifolium Waldst. & Kit,P. officinale L.,P. oreoselinum (L.) Moench,P. ostruthium L., andP. palustre (L.) Moench accumulate different structural types of coumarins including simple coumarins, linear furanocoumarins, linear dihydropyranocoumarins, angular dihydrofuranocoumarins and angular dihydropyranocoumarins. Linear furanocoumarins, known for various biological activities, include some well-known antifeedants, such as bergapten, isopimpinellin, and xanthotoxin. The aim of this investigation was to screen the diverse coumarins fromPeucedanum for insecticidal activity. LC was used to analyze and isolate coumarins for the bioassays. A growth inhibition bioassay with 17 derivatives, comprising all structural types fromPeucedanum, carried out withSpodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) as test organism, indicated the majority of the linear furanocoumarins and the angular dihydrofuranocoumarin athamantin as active compounds. Oxygenation of the prenyl residue of linear furanocoumarins decreased activity. Further formation of an ester with angelic acid even resulted in complete inactivity. Five active linear furanocoumarins, bergapten, isopimpinellin, xanthotoxin, isoimperatorin, and imperatorin, and two linear furanocoumarins with a substituted furan ring, peucedanin and 8-methoxypeucedanin, were compared in a dietary utilization bioassay. Relative growth rate (RGR) and relative consumption rate (RCR) divided the tested coumarins in three groups of similar activity. Isopimpinellin and peucedanin slightly decreased RGR and RCR of the treated larvae, and xanthotoxin, isoimperatorin, and 8-methoxypeucedanin heavily decreased RGR and RCR. Bergapten and imperatorin differed by the lowest RGR values and rather high RCR values. The effects caused by these two coumarins indicate specific postingestive toxicity. The results obtained in this study add to the reputation of coumarins to be an effective chemical defense, postulating that chemical diversity is a necessary trait for well-defended plants.     

Effect of nitrogen and water uptake on yield of wheat

For 2 years, field experiments were conducted to study the direct and interactive effects of water and nitrogen uptake at different growth stages on grain yield of wheat, grown on coarse textured alluvial soil of Ludhiana. Twelve treatments comprising 3 irrigation regimes and 4 rates of N were imposed. The N and irrigation regimes showed significant interaction, especially during the drier year. Grain yield was better explained with water uptake and N uptake, when partitioned over different growth stages than with total uptake. The sensitivity factor for water uptake was higher at the reproductive stage ( = 1.60) than at the vegetative ( = 1.05) and maturation ( = 0.38) stages. Contrary, yield was more sensitive to N uptake during the vegetative stage than the reproductive and the maturation stages. Sensitivity of grain yield to water uptake was higher at higher N application rates. Yield predictability was much better (R² = 0.98) when N and water uptake at different growth stages were combined.     

Inhibition of salvinia (Salvinia molesta Mitchell) by parthenium (Parthenium hysterophorus L.). I. Effect of leaf residue and allelochemicals

Parthenium (Parthenium hysterophorus L.) leaf residue (LP, leaf powder) inhibited salvinia (Salvinia molesta Mitchell) biomass and the number of healthy fronds at 0.25% (w/v) and killed the treated plants at and above 0.75% (w/v) in about 5–15 days, depending on the quantity of the residue. At the lethal dose, the LP caused an abrupt desiccation of above-water plant parts, probably due mainly to root dysfunction. This was concurrent with the loss of dehydrogenase activity in, and an increase in solute leakage from, the roots and loss of chlorophylla, b, and total chlorophyll contents in the fronds, resulting in death of the treated plants. The LP appears inhibitory to salvinia through affecting macromolecules—proteins, lipids, and nucleic acids. The inhibitory activity of LP at the lethal dose suspended in water was completely lost when allowed to stand for 30 days under outdoor conditions and promoted growth of the salvinia plants placed in it. The standard allelochemicals, including those present in parthenium LP, except parthenin andp-hydroxybenzoic acid, did not inhibit growth up to 100 ppm. However, parthenin andp-hydroxybenzoic acid killed salvinia plants at 100 and 50 ppm, respectively. Sincep-hydroxybenzoic acid is unlikely to be present at such a high concentration, parthenin appears to be one of the main allelochemicals responsible for the inhibitory effect of parthenium leaf residue on salvinia.A portion of this work was presented at the International Symposium on Weed Management for Sustainable Agriculture held at C.C.S. Haryana Agricultural University, Hissar, India, November 18–20, 1993.     

Studies on relationship between activity and electron density on carbonyl oxygen in sex pheromone mimics of the American cockroach,part XI

From the relationship between structures of the 2-substituents of verbanyl analogs and their sex pheromone activities to the American cockroach, electron density of the carbonyl oxygen atom in the substituent, as estimated by the [¹⁷O]NMR chemical shift, was estimated to be an important factor which influenced the activity, in addition to length of the substituent and the position of the carbonyl group. (+)-Verbanyl methylcarbonate (XX), possessing the highest electron density on the carbonyl oxygen atom, showed the strongest activity among the analogs.For Part X, see Manabe et al., 1983. J. Chem. Ecol. 9:533–549.     

Aldrin epoxidase activity and cytochrome P-450 content of sawfly larvae,Pergagrapta polita Leach (Hymenoptera: Pergidae) feeding on twoEucalyptus species

Aldrin epoxidase and cytochrome P-450 levels were determined in sawfly larvae,Pergagrapta polita Leach. Of the tissues examined the anterior portion of the midgut had the highest levels of aldrin epoxidase activity and cytochrome P-450 content, 3.56 nmol dieldrin produced/min/mg protein and 1.28 nmol/mg protein, respectively. No significant differences in aldrin epoxidase activities were observed between groups of larvae representing the last three larval instars and between larvae feeding on two eucalypt species.     

苏尼替尼对HeLa细胞增殖及3-磷酸甘油醛脱氢酶表达和活性的影响

目的探讨苏尼替尼(Sutent)对HeLa细胞增殖及3-磷酸甘油醛脱氢酶(Glyceraldehyde-3-phosphate dehydro-genase,GAPDH)表达和活性的影响。方法用不同浓度的Sutent作用于HeLa细胞,采用MTT法检测Sutent对HeLa细胞增殖活力的影响;Western blot检测HeLa细胞中GAPDH蛋白表达的变化;GENMED细胞GAPDH活性终点比色法定量检测了GAPDH的活力。结果经Sutent处理24 h后,HeLa细胞的增殖受到明显抑制,且呈浓度依赖性,半数抑制浓度(IC50)为10.283μmol/L;Sutent可明显降低HeLa细胞中GAPDH蛋白的表达量,并能直接抑制GAPDH的活力。结论 Sutent可抑制HeLa细胞的增殖,降低GAPDH蛋白的表达量及活力,显示了其作为多靶点药物的重要研究价值。     

Effect of gross cardiac glycoside content of seeds of common milkweed,Asclepias syriaca,on cardiac glycoside uptake by the milkweed bugOncopeltus fasciatus

Milkweed bugs,Oncopeltus fasciatus, were fed seeds of common milkweed,Asclepias syriaca, that contained differing concentrations of cardiac glycoside. Whole seeds had a mean cardiac glycoside concentration of 4.01 mg equivalents to digitoxin per g dry weight, and seed embryos had a mean concentration of 5.56 mg/g dry weight. Bugs fed these seeds concentrated cardiac glycoside: their mean concentration was 6.85 mg/g dry weight. Milkweed bugs fed seeds of lower cardiac glycoside content sequestered a greater percent of the available glycoside than bugs fed seeds of high glycoside content. The quantitative variation of cardiac glycoside content of the seeds of this single species did not significantly affect the growth of bugs. In a separate feeding preference experiment, bugs were offered seeds of both high (5.18 mg/g dry weight) and low (2.30 mg/g dry weight) cardiac glycoside content. The bugs showed no indication of selecting seeds of either high or low glycoside content.     

Penicillium bilaji and phosphorus fertilization effects on the growth,development, yield and common root rot severity of spring wheat

A strain ofPenicillium bilaji Chalabuda (PB) has recently been commercially released as a seed inoculant to increase phosphorus (P) uptake by wheat (Triticum aestivum L.). The purpose of this study was to compare the effects of drill applied P (15 kg P ha^–1) with PB seed inoculation on early growth, development, P uptake, and grain yield of Stoa spring wheat at four sites in North Dakota.Fertilization with P consistently enhanced early season growth, main stem development, tillering and P uptake. Seed inoculation with PB had little or no effect on these traits. Phosphorus fertilization tended to increase common root rot severity (CRR, incited byCochliobolus sativus (Ito & Kurib) Drechs.), while PB inoculation had no effect. Grain yields were significantly increased by P fertilization at one location. Inoculation with PB also increased grain yield at this location. The reason why PB inoculation increased yield at this location is not evident, as plant growth and P uptake were not enhanced earlier in the season. Averaged across all four sites, PB inoculation increased wheat yields 66 kg ha^–1, which is similar to averaged yield responses reported from the Prairie Provinces of Canada.     

The triglyceride composition,structure, and presence of estolides in the oils ofLesquerella and related species

Members of the genusLesquerella, native to North America, have oils containing large amounts of hydroxy fatty acids and are under investigation as potential new crops. The triglyceride structure of oils from twenty-fiveLesquerella species in the seed collection at our research center has been examined after being hydrolysis-catalyzed by reverse micellar-encapsulated lipase and alcoholysis-catalyzed by immobilized lipase. These reactions, when coupled with supercritical-fluid chromatographic analysis, provide a powerful, labor-saving method for oil triglyceride analysis. A comprehensive analysis of overall fatty acid composition of these oils has been conducted as well.Lesquerella oils (along with oils from two other Brassicaceae:Physaria floribunda andHeliophilia amplexicaulis) have been grouped into five categories: densipolic acid-rich (Class I); auricolic acid-rich (Class II); lesquerolic acid-rich (Class III); an oil containing a mixture of hydroxy acids (Class IV); and lesquerolic and erucic acid-rich (Class V). The majority of Class I and II triglycerides contain one or two monoestolides at the 1- and 3-glycerol positions and a C₁₈ polyunsaturated acyl group at the 2-position. Most Class III and IV oil triglycerides contain one or two hydroxy acids at the 1- and 3-positions and C₁₈ unsaturated acid at the 2-position. A few of the Class III oils have trace amounts of estolides. The Class V oil triglycerides are mostly pentaacyl triglycerides and contain monestolide and small amounts of diestolide. Our triglyceride structure assignments were supported by¹H nuclear magnetic resonance data and mass balances.     

Effect of green manure on the yield,N uptake and floodwater properties of a flooded rice,wheat rotation receiving15N urea on a highly permeable soil

Field studies were conducted for two years on a rapidly percolating loamy sand (Typic Ustochrept) to evaluate the effect of green manure (GM) on the yield,¹⁵N recovery from urea applied to flooded rice, the potential for ammonia loss and uptake of residual fertilizer N by succeeding crops. The GM crop ofSesbania aculeata was grownin situ and incorporated one day before transplanting rice. Urea was broadcast in 0.05 m deep floodwater, and incorporated with a harrow. Green manure significantly increased the yield and N uptake by rice and substituted for a minimum of 60 kg fertilizer N ha^–1. The recovery of fertilizer N as indicated by¹⁵N recovery was higher in the GM + urea treatments. The grain yield and N uptake by succeeding wheat in the rotation was slightly higher with GM. The recovery of residual fertilizer N as indicated by the¹⁵N recovery in the second, third and fourth crops of wheat, rice and wheat was only 3, 1 and 1 per cent of the urea fertilizer applied to the preceding rice crop. Floodwater chemistry parameters showed that the combined use of the GM and 40 kg N ha^–1 as urea applied at transplanting resulted in a comparatively higher potential for NH₃ loss immediately after fertilizer application. The actual ammonia loss as suggested by the¹⁵N recoveries in the rice crop, however, did not appear to be appreciably larger in the GM treatment. It appeared the ammonia loss was restricted by low ammoniacal-N concentration maintained in the floodwater after 2 to 3 days of fertilizer application.     

Effect of birch (Betula pendula) bark and food protein level on root voles (Microtus oeconomus): I. food consumption,growth, and mortality

The effect of protein and birch bark powder (BBP) content of forage on food consumption and growth of root voles (Microtus oeconomus) was studied by feeding young voles with eight different diets for two weeks. Voles ate more when the protein content of forage was moderate (6%) or low (3%), and when BBP was added to the diets, as compared to a high (12%) protein diet without BBP addition. On high and moderate protein diets voles gained weight, whereas on low protein diets they lost weight. Addition of BBP caused reduced growth or weight loss. Consuming a diet with moderate (6%) protein and high BBP (20%) resulted in high mortality (9 of 10 died). These results show that root voles need at least 6% protein for growth and that the effect of birch bark depends on the protein content of the forage.     

Inhibitory effect of parthenium (Parthenium hysterophorus L.) residue on growth of water hyacinth (Eichhornia crassipes Mart Solms.) II. Relative effect of flower,leaf, stem,and root residue

The relative effect of residue of leaf, flower, stem, and root of parthenium (Parthenium hysterophorus L.) on growth of water hyacinth was studied. The inhibitory activity of the residue as shown by its effect on biomass and healthy leaf number (HLN) of treated plants was in the order: leaf and flower >stem >root. Total phenolic acids in the medium after 72 hr of suspending the plant part residue were maximum in flower followed by leaf, root, and stem, successively. The dry leaf powder (DLP) and dry flower powder (DFP) at and above 0.50% (w/v) and dry stem powder (DSP) at 1.00% (w/v) killed water hyacinth in about one month. Dry root powder (DRP) at the highest dose (1.25% w/v) reduced the growth of the treated plants drastically, but the plants recovered after about one month. The DSP at 0.50% (w/v) and DRP at 0.25–0.75% (w/v) supported growth of treated plants, probably due to lower levels of inhibitors, allowing utilization of constituents of the residue as nutrients. Using wheat seedlings as a reference material, it was observed that in aquaculture at different levels of parthenium plant parts residue, water hyacinth plants were much more sensitive to inhibitory activity. Thus, water hyacinth is suggested as a material for bioassay of inhibitory activity of the parthenium plant residue.     

Sex Pheromone of Apple Blotch Leafminer, Phyllonorycter crataegella, and Its Effect on P. mespilella Pheromone Communication

(Z)-10,(Z)-12-Tetradecadienyl acetate (Z10,Z12–14:OAc) and (E)-10,(E)-12-tetradecadienyl acetate (E10,E12–14:OAc) are sex pheromone components of the apple blotch leafminer (ABLM), Phyllonorycter crataegella. Compounds extracted from female pheromone glands were identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses, retention index calculations of EAD-active compounds, and by comparative GC-EAD analyses of female ABLM-produced and authentic (synthetic) compounds. In field experiments in apple Malus domestica orchards in Connecticut, Z10,Z12–14:OAc alone attracted ABLM males. Addition of E10,E12–14:OAc to Z10,Z12–14:OAc at 0.1:10 or 1:10 ratios enhanced attractiveness of the lure. Geometrical isomers Z10,E12- or E10,Z12–14:OAc at equivalent ratios were behaviorally benign and slightly inhibitory, respectively. In field experiments in British Columbia, Z10,Z12–14:OAc plus E10,E12–14:OAc did not attract Phyllonorycter moths, supporting the contention that ABLM is not present in the fruit growing regions of British Columbia. Z10,Z12–14:OAc added to P. mespilella pheromone, (E)-4,(E)-10-dodecadienyl acetate, strongly inhibited response by P. mespilella males. Recognition of the ABLM pheromone blend by allopatric P. mespilella males suggests a phylogenetic relationship and previous sympatry of these two Phyllonorycter spp. If pheromonal attraction of ABLM males were reciprocally inhibited by P. mespilella pheromone, a generic Phyllonorycter pheromone blend could be tested for pheromone-based mating disruption of the apple leaf-mining Phyllonorycter guild in North America.