Determination of Atrazine Residues in Electro-Ultrafiltration Soil Extracts by a Sensitive Enzyme Immunoassay

A sensitive enzyme immunoassay (EIA) based on polyclonal antibodies from sheep was used to screen for atrazine in electro-ultrafiltration (EUF) soil extracts without clean-up. Matrix effects were circumvented by diluting the aqueous EUF extracts. The EUF proved to be a convenient method for the extraction of atrazine residues in soil. The efficiency of EUF appeared to be equivalent to that of organic extraction methods except on weathered residues, which generally resulted in lower yields. Both the combined gas chromatography/automated Soxhlet (GC/Soxtec) and the immunochemical technique EIA/EUF yielded similar data for the 26 soil samples identified as positive (> 0.02 mg/kg) during the first screening of 479 EUF extracts by the EIA.     

Physiological and biochemical characterization of quinclorac resistance in a false cleavers (Galium spurium L.) biotype

The physiological and biochemical basis for quinclorac resistance in a false cleavers (Galium spurium L.) biotype was investigated. There was no difference between herbicide resistant (R) and susceptible (S) false cleavers biotypes in response to 2,4-D, clopyralid, glyphosate, glufosinate-ammonium, or bentazon. On the basis of GR(50) (growth reduction of 50%) or LD(50) (lethal dose to 50% of tested plants) values, the R biotype was highly resistant to the acetolactate synthase (ALS) inhibitor, thifensulfuron-methyl (GR(50) resistance ratio R/S = 57), and quinolinecarboxylic acids (quinclorac R/S = 46), resistant to MCPA (R/S = 12), and moderately resistant to the auxinic herbicides picloram (R/S = 3), dicamba (R/S = 3), fluroxypyr (R/S = 3), and triclopyr (R/S = 2). The mechanism of quinclorac resistance was not due to differences in [(14)C]quinclorac absorption, translocation, root exudation, or metabolism. Seventy-two hours after root application of quinclorac, ethylene increased ca. 3-fold in S but not R plants when compared to controls, while ABA increased ca. 14-fold in S as opposed to ca. 3-fold in R plants suggesting an alteration in the auxin signal transduction pathway, or altered target site causes resistance in false cleavers. The R false cleavers biotype may be an excellent model system to further examine the auxin signal transduction pathway and the mechanism of quinclorac and auxinic herbicide action.     

Collection of plant-genetic resources in the Georgian SSR 1986

Summary After having finished in 1985 the collection of plant-genetic resources in Western Georgia (the results have been summarized in some tables) joint activities for the collection of indigenous taxa of cultivated plants began for Eastern regions of the Georgian SSR in 1986. The mission took place within the rayon Dueti, which is highly differentiated in geographical respect and stretches beyond the main ridge of the Great Caucasus. Althogether 265 samples could be collected, grain legumes and vegetables represent the most numerous groups but the amount of cereal accessions is not much less; this contrasts sharply with the results from the missions in Western Georgia. The gene-erosion is very advanced in Dueti too, especially for cereals.Triticum carthlicum, T. dicoccon and naked barleys have disappeared within the last decades from the fields. However in isolated settlements the cultivation of old local races ofT. aestivum as well as of barley and rye had been maintained up till now. For breeding purposes and botanically interesting material could be collected also from vegetables, spice plants and grain legumes. Some examples have been shortly characterized.

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Sammlung pflanzen-genetischer Ressourcen in der Georgischen SSR 1986

Zusammenfassung Nachdem 1985 die Sammlungen pflanzen-genetischer Ressourcen in Westgeorgien abgeschlossen wurden (in einigen Tabellen werden die Sammelergebnisse kurz zusammengefaßt), wurde 1986 die gemeinsame Sammeltätigkeit zur Erfassung indigener Kulturpflanzen-Sippen in östlichen Gebieten der Georgischen SSR aufgenommen. Die Reise führte in den Rayon Dueti, der geographisch sehr differenziert ist und bis jenseits des Kaukasus-Hauptkammes reicht. Es konnten insgesamt 265 Proben gesammelt werden, unter denen Körnerleguminosen und Gemüse den Hauptanteil einnehmen, denen aber die Getreide (im Gegensatz zu den Sammelergebnissen in Westgeorgien) nur wenig nachstehen. Die Generosion ist auch hier vor allem bei den Getreiden sehr weit fortgeschritten;Triticum carthlicum, T. dicoccon sowie Nacktgersten sind in den letzten Jahrzehnten aus dem Anbau verschwunden. Jedoch hat sich in entlegenen Siedlungen noch die Kultur alter Lokalsorten vonTr. aestivum sowie von Gerste und Roggen erhalten. Auch von Gemüsen, Gewürzpflanzen und Körnerleguminosen konnte botanisch und züchterisch interessantes Material gesammelt werden. Einige Beispiele davon werden kurz charakterisiert.

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- 1986

1985 - ( ¶rt;), 1986 , . ¶rt; , . , , 265 , , , , . ¶rt;, , Triticum carthlicum, T. dicoccon . , Tr. aestivum . , , , . .

     

Taxonomy and evolution of cultivated plants: Literature review 1980/1981

Summary Important papers on taxonomy and evolution of cultivated plants published in 1980 and 1981 were compiled and briefly discussed.

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Taxonomie und Evolution der Kulturpflanzen: Literaturübersicht 1980/1981

Zusammenfassung Wichtige Arbeiten über Taxonomie und Evolution der Kulturpflanzen aus den Jahren 1980 und 1981 wurden zusammengestellt und kurz kommentiert.

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: 1980–1981 .

, 1980 1981 . .

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Herrn Prof. Dr. Dr. h. c. mult. H.Stubbe aus Anlaß der 80. Wiederkehr seines Geburtstages gewidmet.     

Taxonomy and evolution of cultivated plants: Literature review 1988/1989

Summary Important papers on taxonomy and evolution of cultivated plants published in 1988 and 1989 were compiled and briefly discussed.

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Taxonomie und Evolution der Kulturpflanzen: Literaturübersicht 1988/1989

Zusammenfassung Wichtige Arbeiten über Taxonomie und Evolution der Kulturpflanzen aus den Jahren 1988 und 1989 wurden zusammengestellt und kurz kommentiert.

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: 1988–1989

, 1988 1989 . .

     

Estimating balanced structure areas in multi-species forests on the Sierra Madre Occidental,Mexico

• Introduction   

This study presents a method for estimating the minimum area which exhibits a balanced diameter distribution, and the corresponding number of trees, for different tree species and forest types in the Santiago Papasquiaro region in the State of Durango, Mexico. The balanced structure area is defined as the minimum contiguous area that is required for sustainable management of a multi-sized selection forest. A multi-sized forest represents a balanced structure unit if the relationship between harvest and growth can be maintained, using a defined target diameter distribution and disregarding major natural disturbances. The study is based on 17,577 sample plots in uneven-aged forests, which are selectively harvested by local communities.     

Investigation of sorbate-induced plasticization of Pahokee peat by solid-state NMR spectroscopy

Purpose

Sorbate-induced swelling and plasticization of sorbent have been linked to sorption hysteresis of organic compounds in the natural organic matter of isolated humic acids, soils, and coals. The above processes, which have important implications for the fate and bioavailability of organic and inorganic contaminants, are mostly based on macroscopic changes and require molecular-level confirmation. This study aimed to investigate the presence or absence of sorbate-induced plasticization of Pahokee peat soil as a function of different sorbates.

Materials and methods

The plasticization of Pahokee peat soil was studied upon sorption of different proton-free solutes including C₆D₆, CDCl₃, CCl₄, C₂Cl₄, CBr₄, C₆D₅Cl, and C₅D₅N, covering apolar and polar aromatic and aliphatic compounds. The swelling and plasticization of Pahokee peat soil were verified at the molecular level by ¹H wideline and two-dimensional wideline separation (2D WISE) NMR. The use of ¹H wideline shapes is the traditional technique for studying molecular dynamics but hampered by the lack of spectral resolution, with one dimension displaying ¹³C chemical shifts and the second showing ¹H wideline shapes, is capable of providing information on molecular dynamics of specific functional groups.

Results and discussion

Our results showed that the segments of Pahokee peat soil sorbed with C₆D₆, C₂Cl₄, and C₅D₅N became more mobile, but the changes due to the plasticization were small. Both C₆D₆ and C₅D₅N selectively increased the mobility of specific components, C₆D₆ of the nonpolar alkyl domains, and C₅D₅N of both the nonpolar alkyl domains and aromatic components.

Conclusions

Some liquid solutes at high concentrations (2–5 wt%) are capable of slightly “softening” natural organic matter of a soil, and this provides support for the hypothesis that natural organic matter in Pahokee peat soil is in a glassy state that is subject to plasticization.

     

Differences in the chemical composition of dissolved organic matter from waste material of different sources

The chemical composition of waste-material-derived dissolved organic matter (DOM) was characterized by chemolytic analyses and ¹H, ¹³C and ³¹P nuclear magnetic resonance (NMR) spectroscopy. Dissolved organic matter was extracted by water from an aerobic fermented urban waste compost, a sewage sludge and a pig slurry and then fractionated using the XAD-8 method. The amount of water-extractable dissolved organic carbon (DOC) ranged from 3% in the sewage sludge to 22% in the pig slurry. Dissolved organic matter isolated from pig slurry was equally distributed between hydrophilic and hydrophobic DOC, whereas in the sewage-sludge-derived material the hydrophobic fraction was predominant. Dissolved organic C from the urban waste compost was mainly within the hydrophilic fraction. Wet-chemical analysis and ¹H- and ¹³C-NMR spectra showed that both DOM fractions from the urban waste compost were low in neutral, acidic and amino sugars as well as in lignin-derived compounds. In turn, the materials were rich in low-molecular-weight aliphatic compounds. The chemical structure of both fractions is probably the result of the intensive transformation of urban waste compost during its fermentation. The hydrophilic fractions of DOM from sewage sludge and pig slurry contained considerable amounts of carbohydrates but were also rich in low-molecular-weight aliphatics. The respective hydrophobic fractions had the largest contents of CuO-extractable phenols which may in part derive from sources other than lignin. By contrast with the other materials, the hydrophobic fraction from the pig slurry seemed to contain polymeric rather than low-molecular-weight material. The ³¹P-NMR spectrum of the hydrophilic DOM fraction from urban waste compost did not show signals of inorganic or organic P compounds while the spectrum of the hydrophobic fraction revealed traces of monoester P, diester P, and orthophosphate. ³¹P-NMR spectroscopy suggested that both the hydrophobic and hydrophilic fractions from pig slurry did not contain organic P. The hydrophilic DOM fraction from sewage sludge contained orthophosphate, organic monoester P and a little pyrophosphate. The hydrophobic fraction contained mainly organic diester P and smaller amounts of teichoic acids and organic monoester P. Considering that water-soluble fractions of urban waste compost contained no easily plant-available P and a low content of labile organics, we conclude that this material contains less labile nutrients and is more refractory than the soluble constituents of pig slurry and sewage sludge.