John P. Clarkson

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The release and survival of ascospores of a UK Sclerotinia sclerotiorum isolate were studied. Apothecia placed in a spore clock apparatus with different lighting regimes at 15 degrees C released ascospores continuously with an increasing rate for the duration of experiments (72-84 h). Spore release was not confined to light or dark periods in alternating(More)
ABSTRACT A predictive model for production of apothecia by carpogenic germination of sclerotia is presented for Sclerotinia sclerotiorum. The model is based on the assumption that a conditioning phase must be completed before a subsequent germination phase can occur. Experiments involving transfer of sclerotia from one temperature regime to another allowed(More)
Thermal imaging has been used in the past for remote detection of regions of canopy showing symptoms of stress, including water deficit stress. Stress indices derived from thermal images have been used as an indicator of canopy water status, but these depend on the choice of reference surfaces and environmental conditions and can be confounded by variations(More)
Antibody to rat liver metallothionein prepared by the method of Brady and Kafka (1979) was used to localise immunoreactive metallothionein using a sensitive DNP hapten sandwich technique applied to formalin fixed wax embedded tissues. Rat tissues examined were liver, kidney and small intestine, taken from normal animals, from animals fasted after receiving(More)
We have examined the relationship between (a) histochemically demonstrable copper using rubeanic acid, (b) copper-associated protein (CAP) using orcein, and (c) immunoreactive metallothionein (MT) using DNP hapten sandwich staining and have correlated these with histological lesions in 95 liver biopsies from patients with conditions associated with hepatic(More)
ABSTRACT The feasibility of developing a forecasting system for carpogenic germination of Sclerotinia sclerotiorum sclerotia was investigated in the laboratory by determining key relationships among temperature, soil water potential, and carpogenic germination for sclerotia of two S. sclerotiorum isolates. Germination of multiple burials of sclerotia to(More)
Blood samples and ileal mucosal samples were collected from 25 patients requiring intestinal resections. Plasma zinc levels were measured using atomic absorption spectrophotometry and enterocyte zinc levels were measured using electron probe X-ray analysis. Plasma zinc values showed a positive correlation with mean enterocyte zinc values, supporting the(More)
Accurate and timely detection of plant diseases can help mitigate the worldwide losses experienced by the horticulture and agriculture industries each year. Thermal imaging provides a fast and non-destructive way of scanning plants for diseased regions and has been used by various researchers to study the effect of disease on the thermal profile of a plant.(More)
Pathogenic isolates of Fusarium oxysporum, distinguished as formae speciales (f. spp.) on the basis of their host specificity, cause crown rots, root rots and vascular wilts on many important crops worldwide. Fusarium oxysporum f. sp. cepae (FOC) is particularly problematic to onion growers worldwide and is increasing in prevalence in the UK. We(More)