The effect of previously infested spruce needles on the growth of the green spruce aphid, Elatobium abietinum, and the effect of the aphid on the amino acid balance of the host plant

The effect of chlorosis induced in needles of Sitka and Norway spruce by the green spruce aphid on growth of the aphid is investigated, and the effect of infestation of the aphid on amino acid levels in Sitka spruce foliage is reported. On both Sitka and Norway spruce green spruce aphids were heavier when reared on chlorotic (previously infested) needles than when reared on green (previously uninfested) needles. The effect was more pronounced on Sitka than on Norway spruce. Infestation of the aphid altered the amino acid balance of Sitka spruce foliage but not the concentration of total amino acids. Possible causes of chlorosis, the influence of individual amino acids on aphid growth, the potential effect of chlorosis on outbreaks of the aphid and the differences in susceptibility of Sitka and Norway spruce to damage by the aphid are discussed.     

SUITABILITY OF SELECTIVE MEDIA FOR RECOVERY OF HEAT-STRESSED ESCHERICHIA COLI O157:H7

Tryptone soya agar (TSA) and three selective media, BCM^1M O157:H7(+) agar (BCM), modified eosin methylene blue agar (MEMB), and sorbitol MacConkey agar (SMAC) were evaluated for recovery of two strains of E. coli O157:H7 (salami and cider isolates) heated at 56, 58, and 60C for up to 60 min in tryptone soya broth (TSB). TSA and MEMB were equally effective at recovery of heat-stressed (56, 58, and 60C) E . coli O 157:H7 and superior to SMAC and BCM (P 0.05). When heated at 56 and 58C, recovery of E. coli O157:H7 on MEMB and TSA was not significantly different (P > 0.05); recovery was poorer on SMAC, followed by BCM (P 0.05). There was no significant difference in recovery of E. coli O157:H7 on BCM and SMAC when strains were heated at 60C (P > 0.05).     

HOME PLACEMENT TESTING OF LAMB CONDUCTED IN SIX COUNTRIES

Consumer placement tests, which are used to assess products in an appropriate context, were performed in 36 households comprising 2 to 8 persons in England, France, Greece, Iceland, Italy and Spain using leg joints from 2 types of lamb raised in each of those countries. Ratings of odor, tenderness, juiciness, flavor and overall liking were different among lamb types and overall, the least tender was the least liked. Variations in ratings of cooking odor given by the cook only, which were most marked by the Greek and Spanish panels, were correlated with assessments of the other qualities given by the whole household. Variations in liking were less among individuals within a household than between households and reduced as the number of individuals in a household increased. The structure of a panel is important and should be taken into account when analyzing and concluding from consumer placement tests.     

Internodal Meristems of Monocotyledons: Further Studies and a General Taxonomic Summary

The occurrence of uninterrupted (UM) and intercalary (IM) meristemsin the internodes of vegetative and/ or reproductive axes isreported for 90 species in 34 familie of monocotyledons. Meristemtype was determined by measuring regions of surface elongationand cell division in developing internodes. Many aquatic andpredominantly tropical families are included. These new dataand previously published information are presented in a summaryof 45 families in 19 orders of monocotyledons (sensu Takhtajan,1969). The distribution of UM's and IM's is about equal amongfamilies and orders. Phylogenetic trends are not apparent inthe distribution. Generally, UM's tend to predominate in vegetativeinternodes, and IM's tend to predominate in reproductive internodes.