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1.
Methanolic extract ofMelia azedarach fruits enriched by washing with petrolether and ethyl acetate was used for laboratory treatments of two lepidopteran pests in Egypt. The experiments were carried out with concentrations of 10, 15, 25, 50, 100 and 1000 ppm in a diet and compared with control insects. In both insects food consumption, weight gain and conversion of ingested food (ECI) in body matter decreased with increasing extract amounts. The conversion of digested food (ECD) was lowered gradually by using higher concentrations ofMelia extract. Some antifeedant activity was observed in larvae ofS. littoralis andA. ipsilon. The percentage of mortality increased with application of higher concentrations ofMelia extract in both species. Starting from 3rd larval instar the larvae of both species reduced significantly their weight until pupation in 25 ppm and higher extract concentrations, while the larval period was prolonged. The pupal weight was significantly reduced at 15, 25 and 50 ppm. At higher concentrations the larvae failed to pupate. Duration of pupal period was affected only inA. ipsilon. All reproduction parameters, as period of oviposition, fecundity, fertility and longevity of males and females were affected using emerged adults from treated larvae with concentrations of 10, 15 and 25 ppmMelia extract. InS. littoralis no adult emerged from pupae originated from larvae treated with 50 ppm and higher amounts and no larva hatched from eggs laid by adults treated with 25 ppmMelia concentration as larvae. In both species the oviposition period was shortened at 15 and 25 ppm extract, the fecundity and fertility were drastically reduced, and the longevity of males and females was reduced. Cross sections of the midgut showed that the epithelial cells are destroyed in both pests. This can be one of the reasons for the observed effects.  相似文献   

2.
Flufenoxuron displayed various effects on the two spotted spider miteTetranychus urticae Koch according to the age and the concentrations tested. Generally, younger immatures were rather susceptible than the older ones. The duration of the developmental period increased due to treatments and reproduction of the succeeding females, at the different concentrations. The number of eggs/♀/10 days was fewer than in the control. Treated females at concentrations ranged between 400–20 ppm, produced none-viable eggs and viability increased by decreasing the concentration down to 1 ppm.  相似文献   

3.
Ｉ－６９杨插穗分别培养在含有不同浓度Ｃｅ（ＮＯ３）３的营养液中，经快速冷冻、冷冻干燥、无水塑料包埋及干刀薄切片法，用Ｘ－射线能谱微区分析测定Ｃｅ及其它无机离子在茎尖分生组织和叶的不同组织中细胞壁、细胞质、细胞核及叶绿体中的含量及分布。在１０ｐｐｍＣｅ（ＮＯ３）３处理下，茎尖中Ｃｅ的含量比对照组和１００ｐｐｍＣｅ（ＮＯ３）３处理组高出近１倍，叶的亚细胞中的Ｋ、Ｐ、Ｓ、Ｆｅ的含量也呈增加的趋势。特别是Ｍｇ的含量增加显著，在保卫细胞的细胞质中Ｍｇ的含量比对照组高出３．５倍，而在表皮细胞的细胞核和液泡中的含量则比对照组高出近１３倍。但在１００ｐｐｍＣｅ（ＮＯ３）３处理下，无机离子在叶中亚细胞微区间的含量则显著下降  相似文献   

4.
Several studies have been conducted on the response of crops to greater concentrations of atmospheric CO2 (CO2 fertilization) as a result of climate change, but only few studies have evaluated this effect on multipurpose agroforestry tree species in tropical environments. The objectives of this study were to quantify differences in growth parameters and in leaf carbon (C) and nitrogen (N) concentrations of Cedrela odorata L. and Gliricidia sepium (Jacq.) Walp. seedlings under current ambient temperature (32°C daytime, 22°C night time) and CO2 (360 ppm) (AMB); CO2 fertilization (800 ppm, 32°C daytime, 22°C night time) (fCO2); elevated ambient temperature (360 ppm, 34°C daytime, 25°C night time) (TEMP); and a combination of elevated temperature (32°C daytime, 22°C night time) and CO2 fertilization (800 ppm) (TEMPxfCO2). Results showed significant differences (P < 0.05) in seedling growth parameters (seedling height, number of stem leaves, leaf area ratio, shoot and root biomass, and shoot/root ratio) between treatments for both tree species. The greatest increases in growth parameters occurred in the TEMP and TEMPxfCO2 treatments compared to the AMB treatment for both tree species. However, growth parameters were significantly lower (P < 0.05) in the fCO2 treatment compared to that of the AMB treatment. Leaf N concentration was 1.1 to 2.1 times lower (P < 0.05) in all treatments when compared to current ambient conditions (AMB) in both tree species, but no significant changes in leaf C concentrations were observed. Results from our study suggested that fCO2 had the greatest negative impact on tree growth parameters, and leaf N concentrations were affected negatively in all treatments compared to current ambient conditions. It is expected that such changes in growth parameters and plant N content may impact the long-term cycling of nutrients in agroforestry systems.  相似文献   

5.
Pomiferin is a unique, prenylated isoflavonoid that can be isolated and purified from the fruits of Maclura pomifera (Osage Orange). The molecule typically is isolated with a small amount of a molecule called Osajin which is structurally similar to Pomiferin but lacks an aromatic hydroxyl group. As a consequence, Osajin has been shown to be a less effective antioxidant than Pomiferin. In vitro studies on Normal Human Dermal Fibroblasts demonstrate that Pomiferin is a potent extracellular matrix protein stimulant, showing increases in collagen, elastin and fibrillin expression comparable or superior to equivalent concentrations of retinol. Ex vivo hair follicle assays demonstrate comparable effects on expression of collagen and elastin at Pomiferin concentrations in the range of 0.05–5 ppm. Taken together, the results from the two assays conducted on different models indicate that Pomiferin may be a very interesting ingredient for topical skin and scalp treatments where modulation of the expression of extracellular matrix proteins is important.  相似文献   

6.
The effect of aqueous solutions of L-arginine, L-glutamic acid and ascorbic acid onMeloidogyne javanica egg hatch, juvenile survival, and maturity and fecundity of nematode females in susceptible tomato roots was investigated. All tested compounds significantly suppressed egg hatchability at all concentrations (1000, 2000 and 4000 ppm). L-arginine proved to be the best one in inhibition egg hatch and achieved the highest inhibition percentages at all tested concentration. Inhibition rate of egg hatch increased by increasing the concentration of amino acids and vitamin. L-arginine and L-glutamic acid and ascorbic acid at 2000 ppm resulted in 100% mortality ofM. javanica juveniles after 7 days exposure. Application of aqueous solutions of L-arginine, L-glutamic acid, and ascorbic acid at 1000 ppm significantly reduced numbers ofM. javanica populations, mature females and eggmasses in tomato roots. The maximum inhibitory effect was obtained by L-arginine acid which surpassed both ascorbic acid and L-glutamic acid, in reducing nematode population (R% were 84.95, 80.11 and 70.4, respectively) and in affecting maturity and fecundity of females (maturity % were 53.7, 54.2 and 67.7 and fecundity % were 39.2, 46.2 and 61.2 for L-arginine acid, ascorbic acid, and L-glutamic acid respectively, in comparison with that of control group).  相似文献   

7.
Maintaining the numbers of wood mice and common voles at an acceptable economic level, especially during years of massive outbreaks, is a major challenge in plant protection. Efforts to reduce the negative effects of rodenticides on the environment, to improve the integrated pest control system, and to minimize risks for human and animal health require investigation of the potentials of cellulose, as a natural product, and sodium selenite as rodenticides. The present study was conducted to determine the sensitivity of these rodent species to bromadiolone (a.i. 0.005 %), sodium selenite (a.i. 0.1 and 0.05 %), and cellulose (a.i. 45 %) baits. All experiments were done using no-choice and choice feeding trials. A low acceptance of cellulose baits was found in the choice feeding trial, and the time of first deaths indicate that stress and hunger increase the death rate in both species. The taste had a negative impact on the acceptability of baits containing sodium selenite. Low bait acceptance of cellulose and sodium selenite resulted in lower mortality of both species. The acquired results indicate that bromadiolone remains a more effective solution than cellulose and sodium selenite for control of wood mice and common voles.  相似文献   

8.
In-vitro and in-situ N mineralization were studied in a natural Acacia seyal stand and in a Eucalyptus camaldulensis plantation in Senegal.Mineralizable N, measured by 20 days in-vitro incubations, averaged 40–50 ppm in Acacia soil and 11–14 ppm in Eucalyptus soil, and reached 3.5 and 2.3%, respectively, of total N. The coarse light fractions (>0.2 mm) of Eucalyptus soil organic matter did not produce any mineral N; about 80% of the mineral N was supplied by the organo-mineral fraction, as against 30–50% in Acacia soil.In-situ mineralization was related to precipitation, and ranged from 18 to 40 ppm over 4 weeks during the rainy season in the Acacia stand where 7–10% of total N was mineralized each year. Under Eucalyptus, N mineralization reached only 10 ppm over 3 weeks in the beginning of the rainy season and then decreased sharply. It was assumed that this decrease was related to a depressive effect of herbaceous root growth, the possible processes of which are discussed.  相似文献   

9.
The effect of various flavonoids, lectins and phenyl β-d-glucoside on larval survival, weights and the activities of digestive (total serine protease and trypsin) and detoxifying [esterase and glutathione-S-transferase] enzymes of Helicoverpa armigera larvae at 5 and 10 days after treatment (DAT) was studied through diet incorporation assay. Flavonoids (quercetin, cinnamic acid, caffeic acid, chlorogenic acid, catechin, trihydroxyflavone, gentisic acid, ferulic acid, protocatechuic acid and umbelliferone) were incorporated in artificial diet at 100, 500 and 1000 ppm, lectins: groundnut leaf lectin (GLL), concavalin (ConA) and phenyl β-d-glucoside at 2.5 and 5 μg mL?1. Flavonoids such as chlorogenic acid, caffeic acid and protocatechuic acid at 1,000 ppm were more toxic to H. armigera larvae at 10 DAT than quercetin, catechin, cinnamic acid, trihydroxyflavone, gentisic acid, ferulic acid and umbelliferone. Larval growth and development were significantly reduced in H. armigera larvae fed on a diet with GLL and ConA at 5 μg mL?1 compared to the larvae fed at 2.5 and 1.25 μg mL?1 concentrations. The enzyme activities of the larvae were significantly reduced in flavonoid-treated diets. The flavonoids such as chlorogenic acid, caffeic acid, gentisic acid, trihydroxyflavone, catechin and protocatechuic acid, and lectins, GLL and ConA can be utilized in insect control programs.  相似文献   

10.
Severe dieback and disorted growth was observed in a 30-year old plantation of coastal Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco, var. mensiesii] growing in the Brittain River Valley in southwestern coastal British Columbia. Shoot, bud and tip dieback, bushy multileadered crowns, enlarged and darkened pith and red to brown discoloration on leading shoots as well as bronzed, necrotic and chlorotic foliage were found to be common features of this plantation.Boron deficiency has been diagnosed as the cause of dieback and distorted growth. Foliar samples from affected trees averaged only 6 ppm boron, well below critical minimum levels of 8–12 ppm reported in the literature for a number of coniferous trees. The average boron concentration in the foliage of unaffected trees growing on upper slopes in the same valley was 14.5 ppm. The site characteristics of the affected plantations were found to be similar to those described by other workers as likely to result in soils low in total boron. A complete nutritional diagnosis carried out on all foliage samples collected also suggested sulphur and magnesium deficiences.  相似文献   

11.
The total S and SO4‐S concentrations of Scots pine (Pinus sylvestris L.) needles growing at a distance of 10–80 km from the metallurgical complex in Monchegorsk in subarctic Russia were measured, and organic S was calculated as the difference between them, in order to study the impact of SO2 (3–28 μg m?3 a?1) on foliar S fractions. Total S concentrations of currentand previous‐year needles collected in April 1991 and July 1992 amounted to 658–2548 ppm, SO4‐S concentrations to 99–1297 ppm and organic S concentrations to 447–1599 ppm. The SO4‐S concentrations and the S/N ratios (0.032–0.113 on a gram atom basis) show that S in excess of the growth requirements of trees was entering the needles at all the five sites studied. Foliar K and Ca, but not Mg, increased with increasing SQ4‐S. It is hypothesized that exposure to SO2 concentrations of ≥2 μg m?3 as a growing season mean together with pollution episodes of ～ 100 μg m?3 h?1 result in an oxidative stress high enough to damage Scots pine needles, which derive SO2 effectively from the atmosphere, and that cellular acidification is a secondary effect.  相似文献   

12.
Single-node leafy cuttings from 8- and 15-month-old seedlings of the large Bornean Dipterocarp Shorea macrophylla (Illipe nut) rooted easily under continuous mist, both with and without the application of auxins. Callus production was greatest in the untreated cuttings. Rate of rooting was enhaced by 1200 ppm and 3600 ppm IBA, but the overall level of rooting after 61 days was unaffected by auxin treatment. In a second experiment, 3600 ppm IBA was found to be more effective than 3600 ppm NAA and mixtures of 1800 ppm NAA + 1800 ppm IBA. Mortality of cuttings was greatest with IBA especially at 10800 ppm. Cuttings from the second node below the apex rooted best, with rooting ability of those from nodes 3, 4 and 5 being progressively worse, and mortalities rising with distance from the apex. Cuttings from the uppermost node, which included the developing apex, had the lowest rooting ability. When continuous misting was replaced with misting for alternate hours, rooting was still good, but the absence of misting overnight resulted in much increased cutting mortality and, subsequently, in decreased rooting. It is suggested that Shorea macrophylla could be domesticated for fruit or timber production by the propagation of superior clones.  相似文献   

13.
Ethylene concentrations were determined in gas samples extracted from sealed holes made in the sapwood and heartwood of stems of 70-100-year-old Scots pine (Pinus sylvestris L). Gas could be collected from the heartwood holes by lowering the pressure by means of a large syringe. However, attempts to extract gas from air spaces in the sapwood with the same technique failed, presumably because of lack of an interconnected system of gas-filled canals. High ethylene concentrations, usually in excess of 1 ppm, accumulated in the sapwood holes within one day after sealing. Ethylene concentrations in the sapwood rose to 3-7 ppm during the growing season, and decreased to 0.1-0.3 ppm during the winter. In response to extreme drought, sapwood ethylene concentration increased to 30 ppm, followed by a rapid decrease after the onset of rain. Ethylene concentrations in gas samples from the heartwood were consistently lower than 1 ppm. The lowest values, about 0.1 ppm, were found during the autumn and early winter, whereas values around 0.5 ppm were typical from February to August.  相似文献   

14.
The insecticidal effects of deltamethrin, chlorpyriphos-methyl, pirimiphos-methyl, and spinosad were evaluated against adults of Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) and larvae of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae). Spinosad was applied at 1 and 0.5 ppm, deltamethrin at 0.5 ppm, chlorpyriphos-methyl at 2.25 ppm, and pirimiphos-methyl at 4 ppm. All tests were carried out on wheat for E. kuehniella and in maize for P. truncatus, at three temperature levels, 20, 25, and 30 °C. Mortality of the exposed individuals of P. truncatus was measured after 7, 14, and 21 days of exposure, and 60 days later, the progeny production in the treated and untreated substrate was recorded. In the case of Ephestia kuehniella, mortality was assessed after 25 days. Spinosad was highly effective against P. truncatus adults, even at 0.5 ppm, but 1 ppm provided a better “speed of kill” and a higher suppression of progeny production. Mortality of the exposed P. truncatus adults after 21 days of exposure on maize treated with 0.5 ppm of spinosad was 100 %, regardless of the temperature level tested. A complete (100 %) mortality level was also noted in the case of maize treated with deltamethrin and pirimiphos-methyl, while in the case of chlorpyriphos-methyl, mortality at the 21 day exposure ranged between 61 and 90 %. Progeny production was completely suppressed only on maize treated with deltamethrin. In contrast, pirimiphos-methyl was the most effective grain protectant for E. kuehniella, since mortality was usually <99 %. In general, for both species tested, temperature had a significant effect on mortality, but this trend was different at different insecticides.  相似文献   

15.
Summary The uptake of 1-Naphthyl-N-Methyl Carbamate (Sevin) through the roots of plants an its systemic effect The systemic property of the compound 1-naphthyl-n-methyl carbamate applied to the roots of tabac, pea and turnip plants in aquous culture was tested by cagingMyzus persicae, Aphis fabae andPhyllotreta atra, which were used as test insects, on foliages.It was found that the ability of the tested plants to absorb and translocate the compound was very high and resulted on tabac plants, 3 days after infestation with insects: 0, 0, 68.0% and 100% mortality at concentrations of 0, 25, 250 and 2,500 ppm respectivly.On pea plants Sevin caused 46 hours after infestation withA. fabae. 0, 35.1%, 77.6% and 100% mortality at concentrations of 1.2, 12.5, 125 and 1250 ppm respectivly.6 days after infestation of the beetle,Phyllotreta atra, on seeds of rape Sevin caused 0, 12%, 30%, 90% and 100% mortality at concentrations of 0, 25, 50, 75 and 100 ppm respectivily. After the first 48 hours the mortality was under 25% at all concentrations.These results prove undoubtly the systemic property of sevin. Taken the physiological process involved in absorbtion and translocation of this compound in consideration, it might be that sevin acts as growth regulator when applied at low or high concentrations. Sevin at 25 ppm stimulated the tabac plants to absorb more water than at the highest concentration or at untreated stems. Similar effect was found on the length of roots and stems as well of the weight of dry leaves of oil radish at different concentrations.  相似文献   

16.
The comparative molluscicidal activity of different preparations ofBacillus thuringiensis as Thuricide, SAN 401, SAN 402 and SAN 415, onB. alexandrina snails was studied. The results showed that different preparations ofBac. thuring. have a remarkable molluscicidal activity onB. alexandrina snails. However, the obtained results proved thatBac. thuring. with its preparation SAN 415 was the most effective in killing the snails comparing with the other preparations at the same experimental condition. Prolonged exposure ofB. alexandrina to subletal concentration (250 ppm) of SAN 415 delayed its ovipositary activity. Increasing the dose to 500 ppm resulted in a complete loss of egg production. Comparatively exposure of snail groups to the same doses of Thuricide, SAN 401 and SAN 402 resulted only in decreasing its egg laying capacity. These results proved the high potentially effectiveness ofBac. thuring. in its preparation SAN 415 as a biological control agent forB. alexandrina snails. The wayes by which this biological agent acts on the reproductive system of the snails were discussed.  相似文献   

17.
The toxicity of cypermethrin, deltamethrin, fenpropathrin, fenvalerate, methomyl and kelthane-s against the egg stage and the 1st larval instar ofChrysoperla carnea (Steph.) revealed that deltamethrin exhibited magnitude bad side effects against the eggs (LC90=3.35 ppm) as compared with the safest compound kelthane-s (LC90=144 ppm); the figures of the other tested toxicants ranged between 17.6 and 109.2 ppm.It was found that the larval stage needed higher concentrations to achieve similar mortality percentages. LC90 values ranged between 72.2 and 1,176 ppm. Ranking of toxicity was, however, similar to that of ovicidal action.With one table  相似文献   

18.
A gradient survey was carried out in order to compare peroxidase activity in Scots pine (Pinus sylvestris) needles in relation to distance from the industrial centre of Monchegorsk, on the Kola Peninsula in north-western Russia. Apoplastic and total peroxidase activity and sulphur (S), nickel (Ni) and copper (Cu) content in the needles of mature trees were measured on seven plots located between 10 and 110 km from the pollution source. Peroxidase activities in both current- and previous-year needles increased towards the smelters and showed a positive correlation with needle S, Cu and Ni concentrations. Total peroxidase activities showed a more obvious relationship to the pollution gradient in winter than in autumn. The element contents in the current year needles averaged 1649 ppm (S), 128 ppm (Ni) and 118 ppm (Cu) close to the smelters, 1212 ppm (S), 37 ppm (Ni) and 67 ppm (Cu) at a distance of 40 km and 831 ppm (S), 7 ppm (Ni) and 1 ppm (Cu) at the most distant sampling plot.This study showed that both the apoplastic and total peroxidase activities responded to heavy metal and sulphur pollution up to 40 km from the smelters in winter, which indicated an increased oxidative stress in this area. The harsh climate conditions and the high pollution levels may have had additive effects. However, as peroxidases are considered a general indicator of stress, it is not possible to evaluate the extent to which single pollutants contribute to this enzyme activity.  相似文献   

19.
采用随机区组田间试验进行叶面喷施。通过对１００ｐｐｍ、３００ｐｐｍ、４００ｐｐｍ、５００ｐｐｍ、７００ｐｐｍ和一个清水对照进行处理和分析,最后得出３００ｐｐｍ可以提高百粒重、座果率、单株产量。  相似文献   

20.
Captan, at concentrations up to 2500 ppm did not affect seed germination of Pinus resinosa Ait. However, concentrations of 500 ppm or higher injured roots, stems, and cotyledons within 13 days. Root injury consisted of collapse of root hair cells, epidermal cells, and cortical cells; cotyledon injury of collapse of epidermal and mesophyll cells.  相似文献   

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