Mini‐cutting technique application in Corymbia and Eucalyptus: effects of mini‐tunnel use across seasons of the year

New Forests - The forestry sector has been able to sustainably satisfy the increasing global demand for forest products, thereby positively impacting the economy, while mitigating climate change....     

Allometric biomass equations for tree species used in agroforestry systems in Uganda

Estimates of above-ground biomass are required for better planning, sustainable management and monitoring of changes in carbon stocks in agroforestry systems. The objective of this study was to develop and compare biomass equations for Markhamia lutea, Casuarina equisetifolia, Maesopsis eminii and Grevillea robusta grown in a linear simultaneous agroforestry system in Uganda. These species were established in single rows in the middle of fields in 1995 from four-month old seedlings. A total of 57 trees were sampled for this study, 13 for M. lutea, 12 for C. equisetifolia, 16 for M. eminii and 16 for G. robusta. Biomass values of the various tree components (stem, branches and foliage) as well as the total above-ground biomass were fitted to linear and non-linear allometric models using total height, diameter-at-breast height (DBH), crown width as predictor variables. Although both DBH and height are typically used as independent variables for predicting above-ground biomass, the addition of height in biomass equations did not significantly improve model performance for M. eminii, M. lutea and G. robusta. However, addition of height significantly increased the proportion of variation explained in above-ground biomass for C. equisetifolia, while DBH did not significantly improve the prediction of biomass. The study confirmed the need for developing species-specific biomass equations.     

Reinvestigation of the proteolytically active components of Bromelia pinguin fruit

Pinguinain is the name given to a proteolytic enzyme preparation obtained from Bromelia pinguin fruits that has been scarcely studied. The present paper deals on the reexamination of the proteases present in fruits of B. pinguin grown in Cienfuegos, Cuba. The preparation (partially purified pinguinain, PPP) showed the main characteristics of the cysteine proteases, i.e., optimum pH within alkaline range (pH 7.2-8.8), inhibition of proteolytic activity by thiol blocking reagents, which is usually reverted by addition of cysteine, a remarkable thermal stability and notable stability at high ionic strength values. Isoelectric focusing and zymogram of PPP revealed the presence of several proteolytic components between pI 4.6 and 8.1. Preliminary peptidase purification by cationic exchange chromatography showed the presence of two main proteolytic fractions with molecular masses of approximately 20.0 kDa, according to SDS-PAGE.     

Effects of commercial thinning,log position in the stem,and cutting width on the surface quality of cants produced by a chipper-canter

Fifteen stems of jack pine (Pinus banksiana Lamb.) of 3 commercial thinned plots (control, moderate, and intensive thinning) and 15 stems of black spruce (Picea mariana (Mill.) B.S.P), both coming from the Abitibi-Témiscamingue region – Canada, were cross-cut into three 2.4?m length sections: bottom, middle, and top logs. Logs were processed with a chipper-canter at three cutting widths (12.7, 19.1, and 25.4?mm), producing chips and a three-faced cant. The middle section of the cant was used to evaluate surface quality across the grain on each face. Roughness and waviness parameters and depth of torn grain were recorded. Knot characteristics were assessed in the three cant faces. Poorer surface quality was found in the lower part compared to the upper part of the cant for both species. At larger cutting widths, jack pine logs coming from a natural stand showed lower surface quality compared to logs from thinned stands. Black spruce waviness increased with the cutting width and stem height. These results were attributed to the increase of forces and vibration when cutting at larger cutting widths, which was worsened by the presence of bigger, more numerous knots at the control plot and in the top logs. Black spruce had deeper torn grain compared to jack pine. Their differences in knot characteristics resulted in a maximum torn grain depth favored by the presence of more knots rather than by bigger knot size. Other knot characteristics, such as the position of the knots in the cant face, the insertion angle of the branch and the distribution of the knots around the log, should be studied to better understand the relationship between torn grain formation and knottiness.     

Production of Haploid Sugar Beet (Beta vulgaris L.) by Culturing Unpollinated Ovules

The culture of unpollinated ovules is shown to be a suitable system for the production of haploid sugar beet (Beta vulgaris L.). The yield of haploids depended upon the genotype and varied between 0 and 13 % with a mean of 1.0 %. Haploid plants could be produced from approximately 50 % of all genotypes examined. The majority of the haploids isolated (about 90%) maintained the haploid genome level during the in vitro culture and propagation; 10% of the haploid clones showed a spontaneous doubling to the diploid genome level.     

From wine to pepper: rotundone, an obscure sesquiterpene, is a potent spicy aroma compound

An obscure sesquiterpene, rotundone, has been identified as a hitherto unrecognized important aroma impact compound with a strong spicy, peppercorn aroma. Excellent correlations were observed between the concentration of rotundone and the mean 'black pepper' aroma intensity rated by sensory panels for both grape and wine samples, indicating that rotundone is a major contributor to peppery characters in Shiraz grapes and wine (and to a lesser extent in wine of other varieties). Approximately 80% of a sensory panel were very sensitive to the aroma of rotundone (aroma detection threshold levels of 16 ng/L in red wine and 8 ng/L in water). Above these concentrations, these panelists described the spiked samples as more 'peppery' and 'spicy'. However, approximately 20% of panelists could not detect this compound at the highest concentration tested (4000 ng/L), even in water. Thus, the sensory experiences of two consumers enjoying the same glass of Shiraz wine might be very different. Rotundone was found in much higher amounts in other common herbs and spices, especially black and white peppercorns, where it was present at approximately 10000 times the level found in very 'peppery' wine. Rotundone is the first compound found in black or white peppercorns that has a distinctive peppery aroma. Rotundone has an odor activity value in pepper on the order of 50000-250000 and is, on this criterion, by far the most powerful aroma compound yet found in that most important spice.     

Lindane Biodegradation by Defined Consortia of Indigenous Streptomyces Strains

The current study aimed to compare lindane degradation by pure and mixed cultures of Streptomyces sp. Cell-free extracts were assayed for potentiating dechlorinase activity and, based on these results, consortia of two to six microorganisms were assayed for their growth on and degradation of lindane. Furthermore, the role of bacterial consortia of lindane-degrading strains was examined in lindane decontamination soil assays. Four actinobacteria, previously isolated from a pesticide-contaminated area, were selected because of their tolerance to lindane and their ability to use the pesticide as sole carbon source. These strains as well as Streptomyces sp. M7 and Streptomyces coelicolor A3 were used to study specific dechlorinase activity (SDA) and lindane removal in mixed cultures. Pure cultures presented SDA in the presence of 1.66 mg L^-1 lindane as carbon source. SDA was improved by certain mixed cultures until 12 times compared with pure cultures. Mixed cultures with two, three, and four strains showed maximum lindane removal of 46% to 68%, whereas combinations of five and six strains did not efficiently remove the pesticide from the culture medium. The Streptomyces sp. A2, A5, M7, and A11 consortium presented the lowest ratio between residual lindane concentration and SDA and could be a promising tool for lindane biodegradation.     

Study of the influence of alcoholic fermentation and distillation on the oxygen-18/oxygen-16 isotope ratio of ethanol

A laboratory procedure for the analysis of the oxygen-18/oxygen-16 isotope ratios of ethanol derived from sugars and fruit juices by pyrolysis-isotope ratio mass spectrometry (IRMS) has been applied to the study of isotopic fractionation induced by the isotope effects of fermentation and distillation. For both processes, an experimental model has been established to describe and explain the observed fractionation phenomena. It is shown that reproducible results can be obtained when appropriate analytical conditions are used. Moreover, the ability of ethanol to act as a reliable indicator of the (18)O/(16)O ratio of sugars in orange juice (and therefore to be used as an internal reference for detecting water addition) is demonstrated both in theory and in practice.