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SUMMARYOxygen convective uptakes in gas exchange cycles were directly recorded in early diapause pupae of Pieris brassicae L. (Lepidoptera; Pieridae) by means of O 2 coulometric respirometry. This method was combined with flow-through CO 2 respirometry, the two systems being switchable one to the other. During recording with both systems, measurements were also taken with infrared actography. The pupae displayed short discontinuous gas exchange cycles lasting 40-70min. No true C phase was found by flow-through measurements; instead, flutter opening of the spiracles with discrete convective O 2 uptakes began shortly after the O phase whereas CO 2 release was suppressed by the inward directed passive suction ventilation. The F phase was characterized by a series of small CO 2 bursts (flutter events). Between these bursts, novel sub-phase 'miniflutter' was observed, which consisted of six to 10 miniature inspirations without any CO 2 emission. During the flow-through measurements, oxygen convective uptakes were indirectly recorded by the infrared actograph as sudden extensions (lengthening) of the abdominal segments at each spiracular microopening.

The aim of the present study was to determine the influence of mineral and peat soil condition on the growth, yield and nutrient uptake of some half-highbush blueberry cultivars. The peat soil experimental site was located in a harvested (milled) peat field. Four half-highbush blueberry (Vaccinium spp.) cultivars (five- and six-year-old plants) were used in the experiment: ‘Aino’, ‘Alvar’, ‘Arne’, and ‘Northblue’. Environmental conditions exercised a considerable influence on biological processes of half-highbush blueberry, at the same time, a genotype-based variation was observed. Cultivar ‘Northblue’ had a higher yield in mineral soil and ‘Aino’ had the highest yield in peat soil considering the average of two years. The peat soil condition in the harvested peat field provided a better supply of nutrients for blueberry bushes compared to mineral soil and this, in its turn, secured better growth and a higher yield of blueberry bushes.

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