TIME-INTENSITY EVALUATION OF ORAL BURN1

Temporal oral burn profiles for cinnamaldehyde, piperine and capsaicin were quantified using time-intensity (TI) parameters. Despite large judge-to-judge variation, TI profiles for eaters and noneaters of chile peppers differed significantly. Eaters had lower maximum intensities, shorter total times, and slower maximum rates of onset and decay. Judges with substantial desensitization also had shorter time-to-maximum intensities. Desensitized judges not only scored the burn of capsaicin as less intense, but also the burn of cinnamaldehyde and piperine. The burn of cinnamaldehyde solutions increased and decayed quickly; whereas, burns due to piperine and capsaicin increased and decayed slowly. Capsaicin compared to cinnamaldehyde, had time-to-max, plateau time, and total time that were 1.5, 2.0 and 3.0 fold larger; whereas, the maximum rates of onset and decay were 0.7 and 0.2 fold smaller, respectively. Temporal differences are believed to reflect differences in neural pathways for the irritant species.     

Effect of Light Intensity on Adaptation of Dunaliella to Very High Salt Concentrations

Light intensity was found to have a strong effect on the adaptationto high salt concentrations of a green microalga, Dunaliellaparva, normally grown at low and medium salt concentrations.At high light intensities (200 µmol m^–2 s^–1)the cell glycerol content increased in parallel with an increasein external salt concentration; protein synthesis and cell divisioncontinued with no period of arrest. At low light intensitiesno glycerol synthesis occurred as the external salt concentrationwas raised; protein synthesis and cell division were equallyarrested. The importance of high light intensity during theinitial phase of increase of salt concentration was demonstratedand was found to be a requirement for protein synthesis andcell division. In experiments designed to discover the effectof light intensity on cells growing in media in which the saltconcentration was kept constant, it was confirmed that the lightintensity needed for growth increases as the salt concentrationof the medium is increased. Key words: Dunaliella, salt concentration, light intensity, growth rates     

Bank voles in linear habitats show restricted gene flow as revealed by mitochondrial DNA (mtDNA)

Genetic structure of bank vole populations in linear river bank habitat in southeast Norway was determined from analyses of DNA sequences for the mitochondrial D-loop. Animals were sampled at sites separated by 1 km, along two forested river banks separated by ≈ 100 m of open water. Twenty-six distinct haplotypes were found among 120 voles. The voles showed significant deviation from panmixis on both sides of the river. Animals from the same site or from sites 1 km apart were more likely to share haplotypes than animals 2 km apart or more. Common haplotypes were widespread on both river banks, and had a wider distribution than relatively rare haplotypes. Some rare haplotypes were found on both banks, but most were restricted to a single bank. The results suggest that short-term gene flow may be restricted for female bank voles in linear habitats. Female territorial behaviour may vary with habitat geometry. In the linear habitat described here, females defend only two territorial borders and may effectively limit female dispersal. Results were compared to a previous study of bank voles from this region in a two-dimensional habitat. Gene flow in the linear habitat was much more restricted than gene flow in the two-dimensional habitat. Probable mechanisms underlying this difference are discussed.     

Palaeofloristic assemblages and palaeoecology of the Lower Oligocene Bembridge Marls, Hamstead Ledge, Isle of Wight

A sequence of nine, plant-macrofossil-bearing horizons has been recognized in the Lower Oligocene from the Isle of Wight, England. The plant fossils are contained in finely laminated, olive-brown to black silty-clays and clays. Some horizons exhibit rhythmic alternation of sediment couplets; others show evidence of bioturbation and rootlet penetration. These horizons are included within a sequence of finely laminated greenish grey silty-clays and clays, largely devoid of plant macrofossil material. The plant-bearing horizons contain abundant fruits, seeds, fern sporangia, Azolla megaspores, and rare leaves. The nearest living relatives of the fossils all inhabit an aquatic or marginal aquatic environment. The associated fossil fauna includes lake bottom and lake margin species. The palynoflora of the plant-bearing and immediately underlying horizons includes large numbers of planktonic algae and limited representatives of a forest vegetation. It shows a strong relationship between the occurrences of Sparganiaceaepollenites pollen and of Typha macrofossils. Palaeoecological interpretations of this plant-fossil-bearing sequence are discussed with particular reference to modern environments.
One new genus and three new species are described. Emendations are presented for four other species. Stratiotes leaf margin teeth are described.     

Seasonal variation in insect abundance among three Australian rain forests,with particular reference to phytophagous types

Monthly sweep net and light trap samples were used to examine seasonal changes in the abundance of insects in subtropical, warm and cool temperate rain forest in New South Wales. Maximum insect abundance, especially of phytophages, coincided with leaf flushing in the canopy trees. Cool temperate insect numbers were highest during the month just following the beech leaf flush, a rapid and synchronous growth event. Conversely, numbers of subtropical insects fluctuated over a longer period, in a pattern similar to the continuous growth of leaves that occurred throughout spring and summer there. The warm temperate was intermediate in its vegetation growth phenology and insect patterns. Rainforest insect abundance varied both temporally and spatially.     

Effect of sowing date on the temperature response of leaf emergence and leaf size in barley

Abstract Rate of leaf emergence of barley grown in the field in each of 2 years was affected by sowing date and, where direct comparisons were possible, it was found that leaves on late-sown plants emerged more quickly. Rate of leaf emergence fluctuated throughout the season, slowing almost to zero in the winter. Much of this variation in rate was removed when the number of leaves was plotted against accumulated temperature rather than time. When emergence rates for each sowing were calculated using a common base temperature they were found to be well correlated with rate of change of daylength. However, it was (bund that base temperature as well as temperature response was affected by date of sowing. The pattern of change of size of leaves was also affected by date of sowing. It appeared that in low temperatures and short days, there was no increase in leaf size from leaf position to leaf position. The responses of leaf emergence, extension and final size to date of sowing appear to adapt the plant to grow quickly when sown early but to cease growth and possibly frost-harden at low temperatures.     

Induction of sporulation of fungi isolated from Dactylis glomerata seed by exposure to near-ultraviolet radiation*

Pure cultures of fifty-two species of plant pathogenic and saprophytic fungi isolated from orchard (cock's-foot) grass seed (Dactylis glomerata L.) were incubated either in total darkness or exposed to a diurnal cycle of near-ultraviolet (NUV) radiation (12 h NUV/12 h darkness). Twenty-four species sporulated only after exposure to NUV including seven species of Drechslera, five species of Fusarium, as well as species olAscochyta, Photna, Septoria, Pyrenochaeta, Rhynchophoma and Stagonospora; six species sporulated moderately in darkness but more profusely following exposure to NUV; twenty species sporulated whether they were irradiated or not; and only two species failed to sporulate. To assess the pathogenic fungal microflora of orchard grass seed accurately, seeds should be incubated under a daily regime that includes NUV to induce sporulation.     

Host ranges, symptoms and amino acid compositions of eight potexviruses

The host ranges, symptom expression and coat protein compositions of eight definitive potexviruses are described and compared. Only limited host range similarity was observed: clover yellow mosaic virus and white clover mosaic virus shared 11 of the 28 host species tested; foxtail mosaic virus and narcissus mosaic virus infected monocotyledons; barrel cactus virus and viola mottle virus had narrow host ranges but had eight of the host species in common. Amino acid analyses of coat proteins showed some similarity among the viruses tested, but little correlation with the different host range types. There was more variation of structurally important amino acids such as lysine, arginine, leucine and proline than might have been expected, but high alanine and low tyrosine, tryptophan, cysteine and methionine were typical of plant virus coat proteins.