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Selection of compounds acting as aphid development and reproduction regulators: Laboratory screening
Newly synthesized compounds were examined in screening tests with the pea aphid, Acyrthosiphon pisum (Harris) for juvenilizing effects. usign the spray-residue method. Two derivatives of 2-(4-hydroxvbenzyl)eyclohexanone bearing a carbamate or an ether group were found to be the most active inhibitors of development and reproduction. Tests with the hop aphid, Phorodon humuli (Schrank) of insecticide-susceptible and multi-resistant biotypes and with the green peach aphid, Myzus persicae (Sulzer) confirmed their biological activity. Cross-resistance between conventional insecticides and juvenoids was not indicated. The formation of supernumerary larvae, where retention of larval cauda and corresponding larval characters were observed and reproduction was entirely suppressed, was recognized as the critical result of the juvenilizing effect. The production of viable progeny was not affected in those aphids which survived treatment and developed normal adult external genitalia. 相似文献
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Jožica Gričar Špela Jagodic Bogoslav Šefc Jelena Trajković Klemen Eler 《European Journal of Forest Research》2014,133(3):551-562
We investigated the structure and width of the dormant cambium and of the increments of phloem and xylem of Quercus robur to estimate their potential as indicators for tree vitality. The samples were taken from three woodlands, two in Slovenia [Krakovo forest (KRA) and Murska Suma (MUS)] and one in Croatia [Kobiljak (KOB)], with reported tree decline. The number of dormant cells seems to reflect the initial capacity of the cambium to accomplish cell division. With the exception of two trees at KRA, cell production was always higher on the xylem side than on the phloem side. The annual phloem increments were narrower, less variable among trees and with clear lower and upper limits. With increased cambial cell productivity, the share of the xylem in the total annual radial increment increased following a curvilinear function. In trees with an annual radial increment >3.5 mm, the xylem size represented more than 90 % of the total radial growth. The anatomical variables analyzed show that the most limiting environmental conditions seem to prevail at KRA, whereas the conditions at MUS seem to be most favorable in terms of radial growth. Analysis of the width and structure of xylem and phloem increments, the number of dormant cambial cells and their inter-relationships can provide additional information on the vitality of oaks. 相似文献
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Mirjana D. Stojanović Dragi R. Stevanović Jelena V. Milojković Mirko S. Grubišić Deana A. Ileš 《Water, air, and soil pollution》2010,209(1-4):401-410
The aim of this article is the determination of uranium accumulation in plants tissue in shoots and roots of corn—maize (Zea mays), grown on two types of soils, pseudogley and chernozem, together with its phytotoxic effect on the plant growth and development. The soils was contaminated with different rates (10 to 1,000 mg U(VI) kg?1) of uranyl nitrate (UO2(NO3)2·6H2O). Vegetative tests performed with maize indicated uranium phytotoxic effect on plant height, yield, and germination of seeds. This effect was stronger on the plants grown on pseudogley in comparison with those grown on chernozem. Soil properties determined the tolerance and accumulation of U in plants. A linear dependence between the content of uranium in soil and in plants tissue, including maximal content of 1,000 mg U?kg?1, indicates that maize could be used for phytoremediation of uranium-contaminated soils. 相似文献
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Jelena Petrović Snežana Dragović Ranko Dragović Milan Đorđević Mrđan Đokić Mirjana Ćujić 《Journal of Soils and Sediments》2016,16(4):1168-1175
Purpose
The area of southeastern Serbia, the P?inja and South Morava River Basins, is under the influence of very strong erosion, and the aim of this study was to investigate the vertical and spatial distribution of the 137Cs in the eroded soils of this area.Materials and methods
Vertical soil profiles were collected with 5-cm increments from the uppermost layer down to 20, 25, 30, 40, and 50 cm of depth, depending on the thickness of the soil layers, i.e., down to the underlying parent rocks. Measurements of 137Cs activity concentration were performed by using the HPGe gamma-ray spectrometer ORTEC-AMETEK (34 % relative efficiency and high resolution 1.65 keV at 1.33 MeV for 60Co), from its gamma-ray line at 661.2 keV.Results and discussion
The mean 137Cs activity concentration across all 18 soil profiles (for all soil layers) was found to be 20 Bq kg?1. In the greatest number of soil profiles, the 137Cs activity concentration was generally highest in the first soil layer (0–5 cm) and decreased with soil depth, while in a few soil profiles, the peak of either the 137Cs activity concentration occurred in the second soil layer (5–10 cm) or the 137Cs activity concentration was almost equal throughout the entire soil profile. The mean 137Cs activity concentration in the first soil layer (0–5 cm) was found to be 61 Bq kg?1, and the high coefficient of variation of 92 % pointed out high spatial variability and large range of the 137Cs activity concentrations in the study area.Conclusions
The obtained results indicate that in the greatest number of soil profiles, 137Cs is present in the upper layers, with concentration decreasing with depth, as is typical in uncultivated soil. Its spatial distribution was very uneven among the surface soil layers of the investigated sites. One of the main reasons for such pattern of 137Cs in the study area may be soil erosion. Additional investigations which would support this hypothesis are required.6.
Skrbić B Durisić-Mladenović N Cvejanov J 《Journal of agricultural and food chemistry》2005,53(6):2171-2175
Trace elements (Cu, Fe, Pb, Hg, Cd, As, Mn, Zn) were analyzed quantitatively in 14 wheat samples collected from fields in all Serbian growing regions, harvested in 2002. Microelements were determined according to an atomic absorption spectrophotometric method. Principal component analyses (PCA) were performed on data matrices consisting of contents of trace elements in wheats (columns) and all Serbian wheat-growing regions (rows). It was found that four principal components account for 87.2% of the total variance in the data. The plot of component loadings showed significant groupings for concentration of some microelements. The component scores indicated the similarities among the Serbian wheat-growing regions. The loading plot reveals that there is no need to measure all of the variables to achieve the same classification. It is enough to measure one variable per group. Naturally, this conclusion is valid only within the limits of the present study of wheat grain samples from different parts of Serbia. 相似文献
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Slađana Č. Alagić Snežana B. Tošić Mile D. Dimitrijević Jelena V. Petrović Dragana V. Medić 《Communications in Soil Science and Plant Analysis》2016,47(17):2034-2045
Inductively coupled plasma optical emission spectroscopy, in combination with calculation of various biological factors, was used in this study not only for a simple illustration of the present status of some essential and non-essential metals such as copper (Cu), zinc (Zn), nickel (Ni), lead (Pb), arsenic (As), and cadmium (Cd) in the grapevine cultivar Rkatsiteli and wild blackberry from East Serbia but also for the estimation of plant bioaccumulation potentials. Great majority of detected metal concentrations were in normal ranges except in few cases: Zn concentrations were at the level of deficiency in almost all plant parts, and some Cu and As concentrations were at the levels that could be considered phytotoxic. Biological accumulation factors provided very informative data on metal accumulation and translocation in both plants and pointed to low accumulation rates of metals except in the case of Cu, Zn, and As in some wild blackberry tissues. 相似文献
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Naturally occurring antimutagenic factors, especially those of plant origin, have recently become a subject of intensive research. Antimutagenic properties of terpenoid fractions of sage (Salvia officinalis) were tested in mammalian system in vivo through examining the ability of sage to decrease the frequency of aberrant cells induced by a potent mutagen. First, groups of mice were treated with three concentrations of sage alone and it was established that the frequency of aberrant cells after treatment with a concentration of 25 microL/kg was not significantly different from the negative control (olive oil), while that found after treatment with the 50 microL/kg concentration differed significantly (chi2(1) = 4.05, p < 0.05). Sage used at a concentration of 100 microL/kg was cytotoxic. Mitomycin C (MMC), known as a potent mutagen, was used for induction of chromosome aberrations. Post-treatment with sage suppressed the effects of MMC significantly. Both concentrations (25 microL/kg and 50 microL/kg) produced a significant decrease in the frequency of aberrations relative to MMC (chi2(1) = 5.42, p < 0.02, chi2(1) = 14.93, p < 0.001, respectively). The percent of aberrations decreased with increasing concentrations of sage. Only nontoxic concentrations of sage without mutagenic effects can be recommended for use as inhibitors of mutagenesis or carcinogenesis. 相似文献
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