Leaf surface sesquiterpene alcohols of the potato (Solanum tuberosum) and their influence on colorado beetle (Leptinotarsa decemlineata Say) feeding

The structures of two previously unknown sesquiterpene alcohols of the potato (Solanum tuberosum) were assigned. The potato alcohols were obtained by steam-distillation, preparative column chromatography, and separation into fractions by HPLC on a silica gel column. The fractions were studied by GC-FID, GC-MS, and NMR spectroscopy. The potato sesquiterpene alcohols were identified as kunzeaol (6-alpha-hydroxygermacra-1(10),4-diene) and ledol. These two compounds were used in feeding tests with larvae and beetles of the Colorado potato beetle (Leptinotarsa decemlineata Say). In a bioassay, kunzeaol was found to act as a feeding attractant for the beetles.     

Are Homes Near Water Bodies and Wetlands Worth More or Less? An Analysis of Housing Prices in One Connecticut Town

Proximity to wetlands and water bodies can be considered an amenity (for open space and recreation value), as well as a possible nuisance (with the potential for flooding or development restrictions), although the overall effect may be different depending on location. Studies of the impacts of wetlands and water on housing prices can also be prone to spatial autocorrelation problems arising from omitted unobservables. McMillen and Redfearn explain that locally weighted regressions (LWRs) can address spatial autocorrelation. In addition to ordinary least squares (OLS), we use LWR to control for spatial effects and analyze how proximity to water bodies and wetland areas impact real sales prices of homes in one Connecticut town in 2000–2009. With OLS regressions, proximity to wetland areas and water bodies are insignificant determinants of the real sale price of homes. When we control for spatial effects with a nonparametric (i.e., LWR) approach, the significance of the water variable is different than from OLS—while greater distance from wetlands leads to an insignificant relationship with housing price, the water distance effect becomes negative and significant. These results imply that incorporating potential spatial heterogeneity in the data is crucial for accurately estimating the direction, magnitudes, and statistical significance of the relationships between environmental variables and housing prices.     

Comparison of Aeration Status Measurements by Clark Sensor (DO) and ODR-Meter during Azolla caroliniana Willd. Growth in the Presence of Cd(II) and Hg(II)

The aim of this study was examination possibility of Azolla caroliniana Willd. to aerate its medium enriched with Cd(II) and Hg(II) and comparison of DO and ODR methods in measurement aeration status of solutions. Azolla system has been chosen to verify the validity of the measuring ODR method in water solution. Water aeration measurements, one of important environmental tests, are performed most often by measurement of dissolved oxygen with oxygen sensors. Other similar method called oxygen diffusion rate is generally used in different porous materials such as soil. Our first objective was to check if these both methods are comparable and may be use exchangeable in water solution. The both types of measurements were performed in medium saturated at different oxygen concentrations. The linear relationship and high correlation (R = 0.89) were found between values of ODR and DO. The object of the second part of our studies was A. caroliniana Willd. (Azollaceae), a floating water fern living in symbiosis with cyanobacterium Anabaena azollae Strasb. (Nostoceae) that fixes atmospheric nitrogen. Azolla plants are used for centuries as a nitrogen biofertilizer. The second aim of our work was to find out, if the fern reduces or increases oxygen concentration in water. The ODR method was used to determine the aeration status of the nutrient solution. During 12 days of the experiment at laboratory conditions, an active role of A. caroliniana in aeration of the nutrient solution containing Cd(II) and Hg(II) was stated.     

Seasonal changes of perlite–peat substrate properties in seedlings grown in different sized container trays

New Forests - Cultivation of seedlings in trays requires the use of specifically developed substrates. This study presents the results of the analyses of selected physical and mechanical parameters...