Effect of harvest time and drying method on biomass production, essential oil yield, and quality of peppermint (Mentha x piperita L.)

In the period from 2000 to 2002, studies on peppermint (Mentha x piperita) herb and essential oil (EO) production have been conducted at Planteforsk, Apelsvoll Research Centre Div. Kise in Norway. The trials were aimed at finding the optimal harvest date and suitable drying methods to maximize EO yield and to obtain a desirable oil quality. Peppermint plants from the first production year (2000 and 2001) and the second production year (2002) were harvested during flowering at three developmental stages (early, full, and late bloom). Biomass and leaf production were recorded, and the water content of the plant material was detected after the application of different drying methods: instantaneous drying at 30, 50, and 70 degrees C and prewilting (ground drying) for 1 or 5 days followed by final drying at 30 degrees C. Finally, plant samples were transferred to The Plant Biocentre at NTNU, Trondheim, Norway, for hydrodistillation and gas chromatography-mass spectrometry (GC-MS) analyses of the EOs. Peppermint oil yield increased from early to full bloom and late bloom (average of all years and drying methods except for 50 and 70 degrees C: 2.95, 4.13 and 4.20 L/daa, respectively) as an effect of biomass production and leaf growth. The flavor-impact compounds, menthol and menthone, reached their optimum at full bloom (43-54 and 12-30%, respectively). Prewilting led to slight decreased EO levels after 1 day (7.7%) and 5 days of ground drying (1.5%) and no EO quality changes, compared to direct drying at 30 degrees C. The plant weight (H2O content) was drastically decreased to the average under 80 and 45% in all years, thus reducing the energy supply and costs for the necessary final drying step.     

Solute concentrations and fluxes of major nutrients in potted red spruce saplings exposed to simulated acid rain treatments

Ninety potted red spruce saplings have been enclosed in open-top fumigation chambers and exposed to simulated acid rain treatments of pH 3.1, 4.1, and 5.1 for two growing seasons as part of a 4 yr study. Original spodosol soil profiles were reconstructed in each 1 m diameter pot with tension lysimeters buried at two depths and drainage spouts installed on the bottom of each pot. All principal fluxes of the major elements are being measured in these ecosystems allowing calculation of precise input-output and internal nutrient budgets. During the first year of treatments, nutrient budgets were strongly affected by enhanced mineralization owing to transplant disturbances, and this masked any treatment effects. Second year budgets indicated the effects of strong acid loading on cation depletion and acidification of soils. For example, nitrate leaching from the subsoil was nearly five times higher in the pH 3.1 treatment than in others and correlated increases in base cation leaching were observed. Significant differences in soil pH among rainfall treatments were also observed. Budgetary calculations demonstrated that at present there are large exchangeable Ca pools available for tree growth, whereas for K, plant requirements were very high relative to K soil pools which may lead to growth deficiencies and/or nutrient imbalances. These results illustrate the potential for the combined effects of tree growth and strong acid loading to deplete the base status of acidic forest soils.     

Maternal Effects on the Expression of Individual Aliphatic Glucosinolates in Seeds and Seedlings of Brassica napus

An investigation into the glucosinolate profile of seed and leaf tissue of F₁ hybrids from reciprocal crosses between B. napus‘Cobra’ and a synthetic B. napus line was undertaken to test hypotheses concerning the site of biosynthesis of seed glucosilates. The profile of the seed aliphatic glucosinolates was dentical to the maternal parent suggesting the absence of glucosinolate biosynthesis and glucosinolate interconversion within the embryo and the transfer of fully formed glucosinolates from maternal tissue into the developing seed. In cotyledons, while there was no evidence for de novo glucosinolate biosynthesis, there was evidence for side chain modication and the interconversion of existing glucosinolates. in true leaves, the glucosinolate profile of the reciprocal F₁ hybrids were identical, and in accordance with that expected from the F₁ genotype.     

Expectation and dopamine release: mechanism of the placebo effect in Parkinson's disease

The power of placebos has long been recognized for improving numerous medical conditions such as Parkinson's disease (PD). Little is known, however, about the mechanism underlying the placebo effect. Using the ability of endogenous dopamine to compete for [11C]raclopride binding as measured by positron emission tomography, we provide in vivo evidence for substantial release of endogenous dopamine in the striatum of PD patients in response to placebo. Our findings indicate that the placebo effect in PD is powerful and is mediated through activation of the damaged nigrostriatal dopamine system.     

Progeny testing for resistance to potato virus Y: a comparison of susceptible potato cultivars for use in testcrosses with resistant parents

Summary For potato breeding or genetical research purposes, the number of copies of a dominant major gene for resistance to potato virus Y in a parent clone can be determined by test-crossing with a susceptible parent and observing the segregation ratio of resistant to susceptible seedlings in the progeny. In a comparison of different susceptible cultivars for use in test-crosses for this purpose, their progenies differed in the clarity of symptoms and parental phenotype proved an unreliable guide. Cvs Maris Piper, Arran Peak and Dr MacIntosh were found to be suitable tester parents, Pentland Squire less so and cv. Désirée was confirmed as having a major gene conferring incomplete resistance. It was found advisable to test-cross with more than one susceptible parent.     

Relationships between growth and productivity of range ewes

The relationships between various measures of growth and productivity of range sheep were investigated, utilizing records of 1,109 range ewes sired by 269 rams. Body weights and degree of maturity of body weight at birth, weaning, 12 mo, 18 mo, 30 mo and absolute growth rate, absolute maturing rate and relative growth rate over various age intervals were studied relative to their relationship with productivity characters. Measures of ewe productivity were average annual production for the 4-yr period, 2 through 5 yr of age, for grease fleece weight, number of lambs born, number of lambs weaned and weight of lambs weaned. Heritability estimates were .31 +/- .11 for grease fleece weight, .42 +/- .12 for number of lambs born, .08 +/- .10 for number of lambs weaned and .03 +/- .10 for weight of lambs weaned. All production characters had positive phenotypic correlations (.04 to .22) with body weight at all ages. Both number of lambs born and weight of lambs weaned had small positive phenotypic correlations with growth rates over the 12- to 18-mo age interval. The genetic correlations between ewe productivity and weights at different ages were variable, ranging from -.71 between weaning weight and grease fleece weight to values greater than 1.00 for correlations between weight of lambs weaned and weights at birth, weaning and 18-mo. Degree of maturity at 12 mo had positive genetic correlations with all production characters. Estimated genetic correlations between number of lambs born and absolute growth rate, relative growth rate and absolute maturing rate over the 12- to 18-mo age interval were positive.     

CANINE CERVICAL DISCOGRAPHY

A technique was developed to perform cervical discography in dogs. The radiographic appearance of 70 normal canine cervical discograms was established. No clinical effects were detected when the contrast medium was injected into the discs. No abnormalities were found in subsequent pathologic examinations. In four dogs with cervical disc disease, dorsal and lateral ruptures of the annulus fibrosus were detected by discography. When combined with myelography, discography allowed differentiation between various causes of spinal compression at intervertebral spaces.