The growth rate and the variation in growth in relation to the stock plant of Hedera canariensis Willd. ‘Gloire de Marengo’

When leaf-bud cuttings from Hedera canariensis Willd. ‘Gloire de Marengo’ were prepared with various stem lengths, the subsequent shoot length was inversely correlated with the stem length below the axil. The shoot growth was also correlated with the size of the leaf of the cutting but not by the position along the stem of the stock plant. Certain stock plants yielded cuttings with significantly greater shoot lengths than did others.The shoot length obtained was variable (coefficient of variation 36%), and this variation was reduced neither by standardising the length of the stem below the axil, nor by standardising the area of the original leaf on the cuttings. However, some stock plants produced less variable cuttings than others, and variability was shown to be inversely correlated with the shoot length of the propagated plants.     

Attempts to immunize cattle against Ostertagia ostertagi infections employing 'normal' and 'chilled' (hypobiosis-prone) third stage larvae.

Immunity to Ostertagia ostertagi infections in calves develops slowly and only becomes manifest towards the end of a grazing season in which they have been exposed to the parasite. In an attempt to hasten the onset of immune reactions, three immunization protocols were set up. Twenty four heifers were allocated into four groups. Beginning in January, animals in two of the groups were inoculated with four 1-monthly increasing dosages of either 'normal' or 'chilled' (hypobiosis-prone) larvae, those in the third group received a single large infection with 'chilled' larvae and those in the fourth group served as non-infected controls. All animals were turned out on a common pasture in late April. Development of immunity was evaluated through determinations of faecal egg counts, live weight gains, serum pepsinogen levels and specific serum antibody responses of three isotypes (IgG1, IgG2 and IgA). Significantly reduced egg excretions in the immunized groups were apparent early in the season, indicating that the immunizations had, in this respect, been efficacious. The 'chilled' and 'normal' larvae seemed equally efficient given as multiple and single infections. A single large dosage of 'chilled' larvae seemed to have adverse effects. Only moderate antibody responses were elicited probably because of low challenge infection level on pasture. Considerable variation in responses existed between and within the four groups, for which reason conclusions regarding correlations between antibody isotype responses and immune effects on parasites could not be made.     

Effects of density,rectangularity and row orientation on apple trees,measured in a multiv ariated experimental design

A single-plant-plot design was found very suitable for a study of growth and yield effect of tree density, rectangularity and row orientation on a wide range of intra and inter-row planting-distances.Densities from about 250 to 40 000 trees per hectare were studied in 2 apple cultivars on 2 weak-growing rootstocks over a period of 8 years. On unpruned trees a maximum yield of 80 tons per hectare of ‘James Grieve’ and about 95 tons of ‘Spartan’ was recorded. At the highest densities these yields were reached 2–3 years after planting.As early as the second to third year the growth was restricted at densities over about 1000 trees per hectare. A higher yield per tree at medium densities than at lower densities for the first fruiting-years is supposed to be an effect of growth resulting in earlier fruiting.A high rate of rectangularity reduced the yield only on densities of 1200–1550 trees per hectare. The lack of a significant effect on lower and higher densities is discussed.The growth and yield of rows oriented North—South were 17% higher than of those oriented East—West.     

Serological survey of the infectious disease status of Old English Game fowl in the lower North Island, New Zealand

AIM: To investigate the serological status of Old English Game (OEG) cockerels for a range of infectious diseases of poultry. METHODS: Standard methods were used to screen serum collected from approximately 200 birds during routine dubbing operations, in 2004 and 2005. RESULTS: There was no serological evidence of infection with Newcastle disease, infectious bursal disease, or Salmonella Pullorum. Antibodies to infectious bronchitis virus, avian encephalomyelitis (AE) virus, Mycoplasma gallisepticum and Mycoplasma synoviae were detected. CONCLUSIONS AND CLINICAL RELEVANCE: The disease status of OEG birds is similar to that of commercial poultry.     

Fire and the nitrogen cycle in california chaparral

Analysis of soils from burned and unburned chaparral indicates that high nitrate concentrations following fire are due to the addition of ammonium and organic nitrogen in the ash. Inhibition of mineralization in unburned chaparral results in low nitrate concentrations. Fluctuations in the amount of soil nitrate in unburned chaparral are the direct result of foliar leaching.     

Long-term study of growth in the New Zealand flatworm Arthurdendyus triangulatus under laboratory conditions

In a 1-year laboratory study of the New Zealand flatworm Arthurdendyus triangulatus, individual growth, degrowth and regrowth were manipulated via the feeding regime, with the compost worm Eisenia fetida as prey. A mean growth rate of 25 mg live weight wk^—1 was evident, individual rates ranging between 18 and 38 mg wk⁻¹. Degrowth was associated with egg capsule deposition for which the maximum rate was 0.5 capsules wk⁻¹. The more egg capsules produced, the greater the adult weight loss, degrowth rates ranging from 8 to 55 mg wk⁻¹. Change in flatworm body weight (gain/loss) also correlated with the length of the food introduction interval, though weight could be maintained for circa 2 weeks. Weight loss was not simply a function of hunger, voluntary cessation of feeding (possibly related to egg capsule production) being a confounding factor. During the growth phase, individual predation rate ranged from 0.9 to 1.1 earthworms wk⁻¹, rate of tissue consumption ranging from 346 to 485 mg wk⁻¹. Conversion efficiencies of earthworm to flatworm tissue were estimated to range between 3.8% and 10.7%. The impact of this exotic planarian on earthworm populations is discussed.     

Ion binding by synthetic macrocyclic compounds

The existence of synthetic macrocyclic molecules with hydrophilic cavities containing multiple binding atoms and with hydrophobic exteriors gives rise to extraordinary possibilities with respect to the design and synthesis of molecules with specific cation and anion binding properties. The preparation of many new macrocyclic compounds has recently been reported, but few practical applications for them have been suggested. From the information available, it is becoming clear that it should be possible to synthesize macrocycles that will have specified, or selected, ion binding properties. Cavity size can be varied to accommodate only those cations or anions within a specified narrow band of sizes. Numbers and types of coordinating atoms can be chosen to give essentially electrostatic or covalent bonding or a combination of the two in a metalmacrocycle complex. The metal ligand bond appears to be predominantly ionic in the case of the cyclic polyethers but the covalent character increases on substitution of sulfur or nitrogen for oxygen donor atoms. The essential hydrophobic exteriors of the macrocycles can be modified by the addition of side chains and groups to facilitate the solution of anions and cations in organic solvents. The structures of many macrocycles can be made to approximate naturally occurring molecules, that is, cyclic polyethers similar to macrocyclic antibiotics of the valinomycin and nonactin types and cyclic polyamines similar to porphyrins. Macrocycles are also useful as model compounds for the study of metal interactions with biological systems. The synthetic macrocycles thus represent an intriguing new area of coordination chemistry, the systematic study of which should lead to many interesting and useful chemical applications in the field of metal complexation in solution.