Bound and extractable ¹⁴C residues in canola (Brassica napus) plants treated with radiolabelled atrazine     

S. DUPONT  S. U. KHAN 《Weed Research》1993,33(1):9-16

The nature and distribution of ¹⁴C atrazine (2- chloro- 4 -ethylamino- 6 -isopropylamino-s-tria- zine) residues in resistant and susceptible canola (Brassica napus L.) varieties were studied. Radiolabelled atrazine was applied to the plants just before the flowering stage and continued for 10 days. The plants were harvested 3, 10 and 25 days after the end of the treatment. The roots, shoots and pods of each plant were exhaustively extracted with methanol. The ¹⁴C distribution between the methanol extracts and the plant matrix fractions (bound residues) was similar for the two varieties. High-pressure liquid Chromatographie analysis of the methanol extracts showed that they contained two unknown metabolites (possibly conjugates) in addition to atrazine. The bound ¹⁴C residues were released by supercritical methanol extraction and analysed by thin-layer chromato- graphy, gas chromatography and high-pressure liquid chromatography. Several ¹⁴C components in the released material were detected. Bound atrazine and its two dealkylated metabolites represented only a very small portion (10–18%) of the total bound ¹⁴C residues in the plants. Résidus ¹⁴C extractibles et liés chez des plantes de canola (Brassica napus) traitées avec de l'atrazine radioactivement marquée La nature et la distribution de résidus d'atrazine ¹⁴C (2-chloro 4-ethylamino-6-isopropylamino-s-triazine) chez des variétés de canola résistantes et sensibles ont étéétudiés. De l'atrazine radiomarquée a été appliquée aux plantes juste avant la floraison et poursuivie pendant 10 jours. Les plantes ont été récoltées 3, 10 et 25 jours après la fin du traitement. Les racines, tiges et gousses de chaque plante ont été complètement extractées avec du methanol. La distribution du ¹⁴C entre les extraits méthanol et les fractions de plantes matricielles (liées) a été similaire pour les 2 variétés. Des analyses HPLC des extraits méthanol ont montré qu'ils contenaient deux metabolites inconnus (probablement combinés) en plus de l'atrazine. Les résidus ¹⁴C liés étaient libérés par une extraction au méthanol supercritique et analysé par Chromatographie en couche mince, Chromatographie gazeuze et HPLC. Plusieurs composés dans le matériel libéré ont été détectés. L'atrazine liée et ses deux metabolites dealklyés représentaient seulement une très petite part (10–18%) de la totalité des résidus ¹⁴C liés dans les plantes. Gebundene und extrahierbare ¹⁴C-Rückstände in mit radioaktiv markiertem Atrazin behandeltem Raps (Brassica napus) Die Art und die Verteilung von Rückständen von ¹⁴C-Atrazin (2-Chlor-4-ethylamin-6-iso- propylamin-s-triazin) wurden in resistenten und empfindlichen Varietäten von Raps (Brassica napus) untersucht. Das radioaktiv markierte Herbizid wurde kurz vor der Blüte und 10 Tage weiter auf die Pflanzen ausgebracht. Die Pflanzenproben wurden 3, 10 und 25 Tage nach dem Ende der Behandlung gezogen. Wurzeln, Sprosse und Schoten wurden erschöpfend mit Methanol extrahiert. Die ¹⁴C-Verteilung in den Methanolextrakten und im Pflanzenmaterial (gebundene Rückstände) war bei beiden Sorten ähnlich. Bei der HPLC-Analyse wurden in den Methanolextrakten neben Atrazin 2 unbekannte Metaboliten (vermutlich Konjugate) gefunden. Die gebundenen ¹⁴C-Rückstände wurden im Überkritischen Verfahren mit Methanol extrahiert und dünnschicht-, gas-und HPL-chromatographisch analysiert. Verschiedene ¹⁴C-Verbindungen wurden gefunden. Gebundenes Atrazin und seine beiden de-alkylierten Metaboliten machten nur eine kleinen Anteil (10 bis 18%) der gesamten gebundenen ¹⁴C-Rückstände aus.  相似文献   

SATURATION PERCENTAGE AS A MEASURE OF SOIL TEXTURE IN THE LOWER INDUS BASIN     

G. A. STIVEN  M. A. KHAN 《European Journal of Soil Science》1966,17(2):255-273

The saturation percentage is related to the mechanical constituents of a soil: and is therefore a quantitative expression of soil texture. Profiles may be described in terms of the S.P.; thus Maps may be drawn showing quantitative changes in texture, and associated statements of the reliability of an S.P. estimate and the probable error of the position of a textural contour be made. Decomposition of the calcium carbonate component should be avoided in routine soil survey work.  相似文献   

Total sulphur amino acid requirement and cystine replacement value for fingerling rohu,Labeo rohita: effects on growth,nutrient retention and body composition     

S.F. ABIDI  M.A. KHAN 《Aquaculture Nutrition》2011,17(2):e583-e594

Two feeding experiments were conducted to quantify the total sulphur amino acid (TSAA) requirement and replacement value of cystine for methionine for fingerling Labeo rohita. In Experiment I, isonitrogenous (380 g kg^?1 CP) and isocaloric (17.90 kJ g^?1 GE) amino acid test diets with graded levels of methionine (4, 6, 8, 10, 12, 14 g kg^?1 dry diet) and 0.4 g kg^?1 cystine were fed to fish (4.62 ± 0.2 cm; 0.66 ± 0.1 g) and methionine requirement determined by analysing absolute weight gain (AWG) (5.48), feed conversion ratio (FCR) (1.26), protein retention efficiency (PRE%) (39%) and energy retention efficiency (ERE%) (85%) data which were best at 10 g kg^?1 methionine of dry diet. In Experiment II, six diets with different ratios of L‐cystine and L‐methionine on equimolar sulphur basis were fed to fish (4.71 ± 0.1 cm; 0.69 ± 0.2 g) under identical conditions. Maximum AWG (5.58), best FCR (1.24), PRE (41%) and ERE (86%) in fish fed Diet IV indicated cystine replacement value to be 40%. On the basis of the broken‐line and second‐degree polynomial regression analyses of results obtained in Experiments I and II, it is concluded that inclusion of TSAA in the range of 25.2–31.31 g kg^?1 of protein is optimum of which 33–39% could be spared by cystine.  相似文献   

Biology of milk thistle (Silybum marianum) and the management options for growers in north-western Pakistan     

MUHAMMAD AZIM KHAN  ROBERT E. BLACKSHAW  KHAN B. MARWAT 《Weed Biology and Management》2009,9(2):99-105

Milk thistle ( Silybum marianum ) is cultivated as a medicinal plant but it also can be a troublesome weed. It is an annual or biennial herb that prefers high rainfall and fertile soils. Milk thistle has become a widespread weed in north-western Pakistan, where it causes yield reductions ≤37% in wheat and poses harvesting problems due to its thorny nature. Shortcomings in cultural practises, such as a low crop seed rate, wide row spacing, broadcast fertilizer, and limited crop rotation have contributed to milk thistle becoming a severe weed problem for farmers in this region. This paper reviews the biology of milk thistle and discusses the possible management options for its control, considering the socioeconomic conditions of farmers in Pakistan.  相似文献   

Complementary effect of zoo compost with mineral nitrogen fertilisation increases wheat yield and nutrition in a low-nutrient soil     

Muhammad S. A. KHAN  Lynette K. ABBOTT  Zakaria M. SOLAIMAN  Peter R. MAWSON  Ian S. WAITE  Sasha N. JENKINS 《土壤圈》2022,32(2):339-347

Excess nitrogen(N) fertiliser use in agriculture is associated with water pollution and greenhouse gas emissions.While practices and programs to reduce N fertiliser application continue to be developed,inefficient fertiliser use persists.Practices that reduce mineral N fertiliser application are needed in a sustainable agricultural ecosystem to control leaching and gaseous losses for environmental management.This study evaluated whether fully or partially replacing mineral N fertiliser with zoo compost(Perth Zoo) could be a good mitigation strategy to reduce mineral N fertiliser application without affecting wheat yield and nutrition.To achieve this,a glasshouse experiment was conducted to assess the complementary effect of zoo compost and mineral N fertiliser on wheat yield and nutrition in a sandy soil of southwestern Australia.Additionally,a chlorophyll meter was used to determine whether there was a correlation between chlorophyll content and soil mineral N content,grain N uptake,and grain protein content at the tillering(42 d after sowing(DAS)) and heading(63 DAS) growth stages.The standard practice for N application for this soil type in this area,100 kg ha^-1,was used with a soil bulk density of 1.3 g cm^-3 to calculate the amount of mineral N(urea,46% N) and Perth Zoo compost(ZC)(0.69% N) for each treatment.Treatments comprised a control(no nutrients added,T1),mineral N only(100 kg N ha^-1,T2),ZC only(100 kg N ha^-1,T7),and combinations of mineral N and ZC at different rates(mineral N at 100 kg N ha^-1+ ZC at 25 kg N ha^-1(T3),mineral N at 75 kg N ha^-1+ ZC at 25 kg N ha^-1(T4),mineral N at 75 kg N ha^-1+ ZC at 50 kg N ha^-1(T5),and mineral N at 50 kg N ha^-1+ ZC at 50 kg N ha^-1(T6)).The T6 treatment significantly increased grain yield(by 26%) relative to the T2 treatment.However,the T7 treatment did not affect grain yield when compared to the T2 treatment.All treatments with mineral N and ZC in combination significantly improved the 1 000-grain weight compared to the T2 treatment.Chlorophyll content was better correlated with soil mineral N content(r = 0.61),grain N uptake(r = 0.62),and grain protein content(r = 0.80) at heading(63 DAS) than at tillering(42 DAS).While ZC alone could not serve as an alternative to mineral N fertiliser,its complementary use could reduce the mineral N fertiliser requirement by up to 50% for wheat without compromising grain yield,which needs to be verified in the field.Chlorophyll content could be used to predict soil mineral N at the heading stage,and further studies are warranted to verify its accuracy in the field.Overall,the application of ZC as part of integrated nutrient management improved crop yield with reduced N fertiliser application.  相似文献   

Comparison of humic acid fractions derived from thermally created plant residues and natural soils: Spectroscopic and elemental analyses   总被引：1，自引：0，他引：1  

Nazmul A. KHAN  Nobuhide FUJITAKE  Yukio NODA  Takeshi SUZUKI  Hiroo OTSUKA 《Soil Science and Plant Nutrition》2006,52(3):349-360

  相似文献   

Bacterial Wilt of Russell Prairie Gentian Caused by <Emphasis Type="Italic">Burkholderia caryophylli</Emphasis>     

Naruto FURUYA  Teruyuki MASUNAGA  Abu Ashraf KHAN  Kazuhiro IIYAMA  Masaru MATSUMOTO  Nobuaki MATSUYAMA 《Journal of General Plant Pathology》2000,66(4):316-322

A new bacterial disease of Russell prairie gentian (Eustoma grandiflorum) was found in Fukuoka Prefecture, Japan, in 1997. This disease was characterized by wilting and yellowing of the foliage. A cross section of the stem of a diseased plant revealed a tan to yellow-brown discoloration of the vascular tissue. A nonfluorescent, aerobic, Gram-negative bacterium was consistently isolated from infected plants. The bacteriological characteristics of 10 isolates of the bacterium coincided with those of the reference strains of Burkholderia caryophylli that were isolated from carnations. The bacterium, as well as the reference strains, attacked Russell prairie gentian and carnation after artificial inoculation and reproduced the symptoms similar to those after natural infections. On the basis of bacteriological characteristics and pathogenicities, the bacterium was identified as B. caryophylli. This is the first report of a disease caused by B. caryophylli on Russell prairie gentian ; therefore, bacterial wilt of Russell prairie gentian is proposed as the name of the disease. Received 5 April 2000/ Accepted in revised form 11 July 2000  相似文献   

Light and electron microscope observations on pathological changes in the gills of the marine fish Lycodes lavalaei Vladykov and Tremblay associated with the proliferation of an unidentified cell     

S. S. DESSER  R. A. KHAN 《Journal of fish diseases》1982,5(5):351-364

Abstract. Pale and swollen gills were observed in 23 of 240 Laval's eelpouts, Lycodes lavalaei Vladykov and Tremblay (Perciformes), taken from several locations off the coasts of Newfoundland and southern Labrador. Light microscopic study of histological sections revealed clusters of unidentified cells ('X-cells') in the basal region of secondary gill lamellae and extending along the latter, between the epithelium and lamellar capillaries. In the electron microscope two types of X-cells were enclosed in a network of cytoplasmic processes from dense 'envelope' cells. Both types of X-cells were bound by a densely-coated limiting membrane and had nuclei with large, dense nucleoli, numerous mitochondria with short vesicular cristae, lipid inclusions, abundant smooth endoplasmic reticulum and small dense inclusions. The Type II X-cells were larger, contained a much greater concentration of lipid and small dense inclusions, and an additional inclusion with a dense core surrounded by a light halo. The X-cells are compared with strikingly similar cells described from epidermal and pseudobranch tumours of marine fish. Although transformation of a host cell by virus or possibly pollution has been suggested, neither the nature nor the origin of the X-cells can be determined.  相似文献   

Persistence and movement of terbacil in peach orchard soil after repeated annual applications*     

P. B. MARRIAGE  S. U. KHAN  W. J. SAIDAK 《Weed Research》1977,17(3):219-225

Terbacil (5-chloro-6-methyl-3-butyluracil) residues did not accumulate in peach orchard soil after seven consecutive annual spring applications of the herbicide at the rate of 4.5 kg/ha although carry-over of terbacil from year to year occurred. Terbacil was lost by degradation and leaching and the time required for a 50% decrease in surface soil concentration was 5–7 months in the sandy loam soil. The major part of the residues was found in the upper 15 cm of the soil profile and smaller amounts were detected to a depth of 60 cm. Terbacil leached readily in prepared columns of sandy loam soil in proportion to the amount of water added. The residual levels of terbacil in the orchard were phytotoxic to oats planted 3 years after the last application.  相似文献   

褐煤腐殖酸对不同土壤上小麦生长的影响   总被引：6，自引：0，他引：6  

M. M. TAHIR  M. KHURSHID  M. Z. KHAN  M. K. ABBASI  M. H. KAZMI 《土壤圈》2011,21(1):124-131

Humic acid(HA),a fairly stable product of decomposed organic matter that consequently accumulates in ecological systems,enhances plant growth by chelating unavailable nutrients and buffering pH.We examined the effect of HA derived from lignite on growth and macronutrient uptake of wheat(Triticum aestivum L.) grown in earthen pots under greenhouse conditions.The soils used in the pot experiment were a calcareous Haplustalf and a non-calcareous Haplustalf collected from Raisalpur and Guliana,respectively,in Punjab Province,Pakistan.The experiment consisted of four treatments with HA levels of 0(control without HA),30,60,and 90 mg kg -1 soil designated as HA 0,HA 1,HA 2,and HA 3,respectively.In the treatment without HA(HA 0),nitrogen(N),phosphorus(P),and potassium(K) were applied at 200,100,and 125 mg kg -1 soil,respectively.Significant differences among HA levels were recorded for wheat growth(plant height and shoot weight) and N uptake.On an average of both soils,the largest increases in plant height and shoot fresh and dry weights were found with HA 2(60 mg kg -1 soil),being 10%,25%,and 18%,respectively,as compared to the control without HA(HA 0).Both soils responded positively towards HA application.The wheat growth and N uptake in the non-calcareous soil were higher than those of the calcareous soil.The HA application significantly improved K concentration of the non-calcareous soil and P and NO 3-N of the calcareous soil.The highest rate of HA(90 mg kg -1 soil) had a negative effect on growth and nutrient uptake of wheat as well as nutrient accumulation in soil,whereas the medium dose of HA(60 mg kg -1 soil) was more efficient in promoting wheat growth.  相似文献