DISSIMILARITIES IN COGNITION OF FLAVOUR TERMS RELATED TO VARIOUS SENSORY LABORATORIES IN A MULTIVARIATE STUDY

A study of dissimilarities in cognitive perception of 20 common flavor terms was carried out by the Sensory Group of Norway. An average cognitive pattern of the flavor terms was revealed from multidimensional scaling (MDS) and cluster analysis (CLU). In general, small but interesting deviations between different sensory laboratories working with various food products were found by a multivariate pattern recognition technique based on principal component analysis (PCA). Suggestions for finding general reference standards for flavor terms are discussed.     

Distribution of planktonic ciliates in highly coloured subtropical lakes: comparison with clearwater ciliate communities and the contribution of myxotrophic taxa to total autotrophic biomass

SUMMARY 1. The planktonic ciliate communities of eleven organically coloured north and central Florida lakes representing a variety of trophic conditions were examined during 1979–80. The total abundance and biomass of ciliates were not significantly different from comparable clearwater lakes and only minor taxonomic replacements were noted at the order level.
2. Timing of population peaks of oligotrophic lakes was dissimilar to clearwater lakes of the same trophic state, but seasonality in meso-trophic and eutrophic lakes resembled patterns described for comparable clearwater lakes.
3. Various ciliate components were strongly correlated with chlorophyll a concentrations, but only moderately correlated to dominant phytoplankton groups. No significant correlations were found between ciliate components and bacterial abundance.
4. Myxotrophic taxa numerically dominated oligotrophic systems, particularly during midsummer, and accounted for a large percentage of the total ciliate biomass. Estimates of the ciliate contribution to total autotrophic biomass indicate that these zoochlorellae-bearing protozoa may account for much of the autotrophic biomass during midsummer periods in coloured lakes, and thus may lead to an overestimation of phytoplankton standing crops available to zooplankton grazers if chlorophyll a is used as a surrogate measure of algal biomass.     

Thigmomorphogenesis: The Interaction of Wind and Temperature in the Field on the Growth of Phaseolus vulgaris L.

Field and laboratory experiments were performed to determinethe interaction of wind and temperature on thigmomorphogenesis(defined here as decreased elongation and increased internodalradial enlargement due to mechanical perturbation). Kidney beanplants (Phaseolus vulgaris L. cv. Red Cherokee Wax) were shelteredor exposed to wind for 10 days. Wind velocity, wind gusting,temperature, light and rainfall were measured for the durationof each of ten experiments. Stem elongation and diameter weremeasured and it was found that thigmomorphogenesis due to windoccurs naturally. There was more internodal secondary xylemproduced in the wind-exposed plants than in the sheltered plants.The experimental data were analyzed by multiple linear regressionand the wind was found to be a significant factor in the predictionof bean stem elongation and thickening. Laboratory experimentsshow that as wind velocity increases, thigmomorphogenesis increasesin an approximate linear fashion. Furthermore, it was foundthat low temperatures interact with mechanical perturbationto reduce the amount of thigmomorphogenesis, both in the fielddue to wind and in the laboratory due to rubbing. Other environmentalfactors do not seem to interact with the wind to modulate thigmomorphogenesiseven though these factors affect plant growth. Phaseolus vulgaris L., kidney bean, thigmomorphogenesis, wind, temperature, ethylene, multiple linear regression     

Breeding of waders (Charadrii) and Brent Geese Branta bernicla bernicla at Pronchishcheva Lake, northeastern Taimyr, Russia, in a peak and a decreasing lemming year

During summer 1991, lemmings occurred at high densities in Arctic tundra at Pronchishcheva Lake in the northeastern Taimyr Peninsula, whereas, in 1992, lemming densities were substantially lower and decreased further during the summer. In 1991, avian predators such as Snowy Owls Nyctea scandiaca, gulls and skuas bred well; Arctic foxes Alopex lagopus were rarely observed in the study area but bred in the immediate vicinity. In both years there was a late thaw, but this did not deter breeding by birds. The insect food supply for waders showed similar patterns of abundance in both years. In 1991, 73 nests of nine species of wader were found within a 14-km² study area, and Dark-bellied Brent Geese Branta bernicla bernicla nested in association with Snowy Owls. The overall density of wader nests was estimated to be 7 per km². Clutches disappeared at only two wader nests and no Brent Goose nests, and the Mayfield estimate of the daily probability of predation for waders was 0.0022. In contrast, the daily probability of predation was 0.20 in 1992, when there was a similar breeding density of waders. Arctic foxes were seen searching for food daily within the study area, and fox droppings were found associated with nests taken by predators. The predicted scenarios for peak and decreasing lemming years (the Roselaar-Summers hypothesis), i.e. low predation and high nest success in the peak year and high predation and low nest success in the decreasing year, therefore occurred.     

The Effect of the Calyptra on the Plane of Guard Cell Mother Cell Division in Funaria and Physcomitrium Capsules

The calyptra influences the plane of division in guard cellmother cells of Funaria and Physcomitrium. Normally, capsulesexpand while sheathed by the calyptra and the axes of the stomataare parallel to the axis of the capsule in both genera. Removalof the calyptra from an elongating sporophyte leads to setathickening prior to capsule expansion and an essentially randomorientation of stomata. If the calyptra is removed from a sporophyteof Funaria at the time the division of the guard cell mothercells is expected, guard cells of abnormal shape and undividedguard cell mother cells are found in unusually high frequency.     

Paramecium Transport by Land Snails

SYNOPSIS. Field observations and experiments in a tropical forest revealed that Paramecium multimicronucleatum and other small aquatic organisms are transported between Heliconia flowers by terrestrial snails of the genus Caracolus . It is probable that dispersal is readily accomplished in tropical forests, and that the presence or absence of Paramecium in a given area therefore is determined by biological interactions.     

Evidence aǵainst self-incompatibility and for genetic lethals in the fern Stenochlaena tenuifolia (Desv.) Moore

Morphofogical studies of Stenochlaena tenuifolia (Desv.) Moore have shown that the inter-gametophytic mating system, as in most Blechnaceae, is based on an initial prolonged arche-goniate condition followed by the formation of antheridia, with a resultant tendency towards outbreeding and the production of heterozygous sporophytes. Subsequent genetic studies indicate that certain sporophytes of this species are heterozygous for lethal genes.