Gas-liquid chromatographic determination of hydrazine in maleic hydrazide formulations and in samples stored at an elevated temperature     

Henk Bakker  Albertus Martijn  Rudolf H. Schreuder 《Pest management science》1983,14(5):470-474

A method is described for the analysis of small amounts of hydrazine in maleic hydrazide formulations. Following derivative formation with pentafluorobenz-aldehyde, the pentafluorobenzaldehyde azine was extracted with hexane and determined by gas-liquid chromatography with electron-capture detection. Recoveries of 72-80% were obtained from samples fortified with 1 and 10 μg of hydrazine. The limit of detection was 0.05 mg kg^?1. Fourteen commercial formulations with maleic hydrazide concentrations ranging from 180-360 g litre^?1 were investigated. The hydrazine content of the maleic hydrazide used in these formulations ranged from less than 0.05 to 53 mg kg^?1. During the storage of two samples at 50°C for 10 weeks, the hydrazine contents increased from 2.2 to 124 and 0.4 to 54 mg litre^?1, respectively.  相似文献   

Effectiveness of preventing flowering of hawthorn in protecting pear orchards from fire blight infection     

Henk J. Schouten 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(1):21-32

Since 1984 when a new Ministerial Regulation on fire blight came into force, there have been 20 protected regions in the Netherlands, where nurseries of rosaceous plants, and pear and apple orchards are extra protected against fire blight. This policy is also necessary to meet the requirements of the European Community (EC) on fire blight. Two of the measures in the protected regions are the prohibition of flowering of the native hawthorn (Crataegus monogyna andC. laevigata), and destruction of blighted plants. In the unprotected regions, flowering is allowed, and destruction of blighted plants is limited to a zone of 500 metres around orchards.For three years, the effectiveness of preventing flowering of hawthorn in protecting pear orchards against fire blight infection was studied in the field. Five test areas of about 3 km × 3 km were chosen with hawthorns and pear orchards. Two of these areas were in protected regions and three in unprotected regions. The more than 50 000 hawthorns in the areas were grouped into 1125 sites of hawthorn. The 126 orchards larger than 0.2 ha contained about 180 000 trees.During the three years light to moderate epidemics of fire blight were observed in the regions. Fire blight occurred in 2.3% of the non-flowering sites and 19.8% of the flowering (or fruiting) sites at least once in 1987, 1988 or 1989. The prohibition of flowering for hawthorn in protected areas was rather well implemented, so that in protected areas a smaller proportion of sites of hawthorns had fire blight (4.1%) than in unprotected areas (14%). Moreover, there were fewer sites per square kilometre in the protected areas (13) than in the unprotected areas (26).In protected areas, 53% and in unprotected areas 59% of the pear orchards had fire blight during 1987, 1988 or 1989. The difference was not significant. The first reason for the ineffectiveness of the preventing of flowering prevention in hawthorn to control fire blight in pear orchards was the inadequate hygiene of the pear orchards in both types of region. If it be assumed that a new focus is most probably initiated by the nearest existing focus, the second reason was that fire blight hardly spread from hawthorn to pear in the period of this study. Spread of fire blight within pear orchards and between pear orchards occurred frequently.  相似文献   

Metabolic diversity in apple germplasm     

Sabaz A. Khan  Yury Tikunov  Pierre‐Yves Chibon  Chris Maliepaard  Jules Beekwilder  Evert Jacobsen  Henk J. Schouten 《Plant Breeding》2014,133(2):281-290

We analysed metabolic diversity in apples from wild species, elite material and a F₁ population, using liquid chromatography–mass spectrometry (LC‐QTOF‐MS). The evaluated elite material appeared to have strongly reduced levels of phenolic compounds, down to 1% of the concentrations in the investigated wild germplasm. In one quarter of the F₁ population, the concentrations of phenolic compounds such as quercetin derivatives, procyanidin, catechin and epicatechin were further significantly reduced, due to accumulation of recessive alleles of putatively leucoanthocyanidin reductase, a structural gene that is located at the top of LG16. In another part of F₁ progeny, putatively glycosylated forms of β‐glycols were up to 50 times more abundant compared to both parents. These metabolites were mapped with high logarithm of odds (LOD) scores at the top of LG8, and progeny that was homozygous recessive for the candidate gene showed the elevated levels. We hypothesize that this was caused by inheritance of non‐functional alleles of enoyl‐CoA hydratase gene. Both examples of transgressive segregation, where some progeny significantly deviated from both parents, were caused by accumulation of recessive alleles.  相似文献   

Costs and effectiveness of on‐farm measures to reduce aquatic risks from pesticides in the Netherlands     

Martha M van Eerdt  Joanneke Spruijt  Erna van der Wal  Henk van Zeijts  Aaldrik Tiktak 《Pest management science》2014,70(12):1840-1849

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The histologic, ultrastructural, and immunohistochemical features of a blastema-predominant canine nephroblastoma.     

R M Simpson  J M Gliatto  H W Casey  W G Henk 《Veterinary pathology》1992,29(3):250-253

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Number blindness: fatal?     

Vaarkamp H 《Tijdschrift voor diergeneeskunde》2004,129(22):768

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The inheritance of resistance to the potato cyst nematode <Emphasis Type="Italic">Globodera pallida</Emphasis> PA3 in wild <Emphasis Type="Italic">Solanum</Emphasis> species with broad spectrum resistance     

Lidwine M. W. Dellaert  Henk Vinke  Karin Meyer 《Euphytica》1988,39(3):105-116

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Experimental dinitro-o-toluamide poisoning in poultry     

F Henk  L Hromatka 《Wiener tier?rztliche Monatsschrift》1967,54(5):336-341

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Phenylpyrazoles,a new class of pesticide: Effects on neuromuscular transmission and acetylcholine responses     

Sjaak F. L. Klis  Nic J. Nijman  Henk P. M. Vijverberg  Joep van den Bercken 《Pest management science》1991,33(2):213-222

Phenylpyrazoles constitute a newly developed class of chemicals with insecticidal and herbicidal properties. In acute toxicity experiments in rats, near-lethal doses of phenylpyrazoles produce neurotoxic symptoms with an unknown mode of action. We have investigated the effects of two phenylpyrazoles, SLA4722 and SLA4685, in the frog neuromuscular junction and in the clonal muscle cell line BC3H-1. In the frog neuromuscular junction SLA4722 at concentrations ? 10^?5 M caused a pronounced increase in the frequency of miniature endplate potentials (MEPPs). SLA4685 caused a similar increase but was less potent. In the clonal muscle cell line BC3H-1, SLA4685 produced a concentration-dependent block of the acetylcholine (ACh) response (IC₅₀ = 2.4(±0.3) × 10^?5 M). At 10^?6 M a slight potentiating effect of SLA4685 on the ACh response was observed. SLA4722 was less potent in this preparation. The increased transmitter release might, at least partly, be responsible for the excitatory effects of the phenylpyrazoles in intact animals.  相似文献   

The road to hell...     

Boissevain I  Vrieselaar H 《Tijdschrift voor diergeneeskunde》2008,133(2):71

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