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A population survey of 1000 7 year old children found a significant excess of wheeze among children whose homes were reported to be mouldy (odds ratio 3 70, 95% confidence limits 2-22, 6-15).The airborne mould flora was quantified by repeated volumetric sampling during the winter in three rooms of the homes of 88 children. All of these had previously completed spirometric tests before and after a six minute free running exercise challenge. Total airborne mould counts varied from 0 to 41 000 colony forming units (CFU)/m3, but were generally in the range 50-1500 CFU/m3, much lower than the concentrations found outdoors in summer. The principal types of fungi identified are all known to be common out of doors, and most were found on at least one occasion in most of the homes. Median and geometric mean total mould counts were not related to reports of visible mould in the home, or to a history of wheeze in the index child. The heterogeneous group of non-sporing fungi (mycelia sterilia) were the only airborne fungi present at significantly higher concentrations in the homes of wheezy children (geometric mean 2-1 v 0 7 CFU/m3. A non-significant increase in total mould counts was observed in the homes of children with a

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Populations of aerobic heterotrophic bacteria, mycelial fungi and yeasts occurring in malting barley were estimated by a plate technique and scanning electron microscopy. There was an increase in the total number of micro‐organisms during germination, although populations declined after kilning. Bacteria dominated on all samples, with progressively lower populations of yeasts and filamentous fungi. There was no obvious spatial distribution of micro‐organisms on the samples although there appeared to be high populations of bacteria and fungal hyphae on the inner surface of the kernels. The dominant groups of aerobic heterotrophic bacteria were presumptively identified as Alcaligenes sp., Arthrobacter globiformis, Clavibacter iranicum, Erwinia herbicola, Lactobacillus spp. and Pseudomonas fluorescens. The principal filamentous fungi were identified as Aiternaria alternata, Aspergillus glaucus (group), Cladosporium macrocarpum, Epicoccum purpurascens, Fusarium avenaceum, Geotrichum candidum and Penicillium spp. The yeasts isolated most frequently were Candida catenulata, C. vini, Debaryomyces hansenii, Hansenula polymorpha, Kloeckera apiculata, Rhodotorula mucilaginosa, Sporobolomyces roseus and Trichosporon beigelii.

To advance our understanding of the underlying processes by which kernel set is regulated in maize (Zea mays L.), leaf photosynthesis, sugars, starch, abscisic acid (ABA), and cytokinin were quantified in plants subjected to water deficit and shade, imposed for 5 d at the pre‐pollination and early post‐pollination stages. Both water and light deprivation, at both stages, decreased kernel set primarily in apical ear regions. Treatments decreased leaf photosynthesis similarly; however, sugar concentrations in reproductive tissues increased in water deficit while they decreased 20 to 50% in shade. During treatments, nonstructural carbohydrate accumulation was nearly halted in both apical and basal florets at the pre‐pollination stage, whereas it was decreased to a greater extent in apical than basal endosperm/nucellus at the post‐pollination stage. Both water deficit and shade increased ABA concentrations in reproductive tissues, but only at the post‐pollination stage was ABA greater in apical than basal ear zones, thus corresponding to effects on kernel set. Treatments did not consistently alter zeatin‐like cytokinin concentrations. We conclude that photosynthate flux and ABA are components of a regulatory system by which water and light deprivation affect kernel set at the post‐pollination stage, while additional factors may underlie effects at the pre‐pollination stage.

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