An analysis of elastic and plastic fruit growth of mango in response to various assimilate supplies

Changes in elastic and plastic components of mango (Mangifera indica L. cv 'Cogshall') fruit growth were analyzed with a model of fruit growth over time and in response to various assimilate supplies. The model is based on water relations (water potential and osmotic and turgor pressures) at the fruit level. Variation in elastic fruit growth was modeled as a function of the elastic modulus and variation in turgor pressure. Variation in plastic fruit growth was modeled using the Lockhart (1965) equation. In this model, plastic growth parameters (yield threshold pressure and cell wall extensibility) varied during fruit growth. Outputs of the model were diurnal and seasonal fruit growth, and fruit turgor pressure. These variables were simulated with good accuracy by the model, particularly the observed increase in fruit size with increasing availability of assimilate supply. Shrinkage was sensitive to the surface conductance of fruit peel, the elasticity modulus and the hydraulic conductivity of fruit, whereas fruit growth rate was highly sensitive to parameters linked to changes in wall extensibility and yield threshold pressure, regardless of the assimilate supply. According to the model, plastic growth was generally zero during the day and shrinkage and swelling were linked to the elastic behavior of the fruit. During the night, plastic and elastic growths were positive, resulting in fruit expansion.     

Integrating social network development into marine protected area management capacity building and institutionalization in the Philippines and Indonesia

1. comprehensive needs assessment;
2. strong collaborative partnerships for programme delivery;
3. clear learning objectives and intended long‐term results; and
4. strong and sustained political will at the local, national, and regional scales.
5. Each MPA site, region, and capacity‐building programme is unique in structure and content, yet what all programmes have in common is that they build on the principles of trust and community building to create a locally relevant format and framework for the network to flourish.

     

Synergistic antioxidative effects of alkamides, caffeic acid derivatives, and polysaccharide fractions from Echinacea purpurea on in vitro oxidation of human low-density lipoproteins

Preparations of Echinacea are widely used as alternative remedies to prevent the common cold and infections in the upper respiratory tract. After extraction, fractionation, and isolation, the antioxidant activity of three extracts, one alkamide fraction, four polysaccharide-containing fractions, and three caffeic acid derivatives from Echinacea purpurea root was evaluated by measuring their inhibition of in vitro Cu(II)-catalyzed oxidation of human low-density lipoprotein (LDL). The antioxidant activities of the isolated caffeic acid derivatives were compared to those of echinacoside, caffeic acid, and rosmarinic acid for reference. The order of antioxidant activity of the tested substances was cichoric acid > echinacoside > or = derivative II > or = caffeic acid > or = rosmarinic acid > derivative I. Among the extracts the 80% aqueous ethanolic extract exhibited a 10 times longer lag phase prolongation (LPP) than the 50% ethanolic extract, which in turn exhibited a longer LPP than the water extract. Following ion-exchange chromatography of the water extract, the majority of its antioxidant activity was found in the latest eluted fraction (H2O-acidic 3). The antioxidant activity of the tested Echinacea extracts, fractions, and isolated compounds was dose dependent. Synergistic antioxidant effects of Echinacea constituents were found when cichoric acid (major caffeic acid derivative in E. purpurea) or echinacoside (major caffeic acid derivative in Echinacea pallida and Echinacea angustifolia) were combined with a natural mixture of alkamides and/or a water extract containing the high molecular weight compounds. This contributes to the hypothesis that the physiologically beneficial effects of Echinacea are exerted by the multitude of constituents present in the preparations.     

Long-term Persistence of Stream Nitrate Concentrations (Memory Effect) Inferred from Spectral Analysis and Detrended Fluctuation Analysis

Previous research in agricultural catchments showed that past inputs of nitrate continue to influence present observations and future characteristics of nitrate concentrations in stream water for a long period of time. This persistence manifests itself as a “memory effect” with a prolonged response of stream water nitrate levels to reductions of nitrate inputs on the catchment scale. The question we attempt to resolve is whether such a memory effect also exists in mountainous catchments with a snowmelt-dominated runoff regime. We analyzed long-term records (∼20 years) of nitrate-nitrogen concentrations measured in stream at three stations on the upper Váh River (Slovakia). Applying spectral analysis and detrended fluctuation analysis, we found a varying degree of persistence between the three analyzed sites. With increasing catchment area, the fluctuation scaling exponents generally increased from 0.77 to 0.93 (fluctuation exponents above 0.5 are usually considered as a proof of persistence while values close to 0.5 indicate “white” uncorrelated noise). The nitrate-nitrogen signals temporally scaled as a power-low function of frequency (1/f noise) with a strong annual seasonality. This increase in persistence might be attributable to the catchment areas upstream the sampling sites. These results have important implications for water quality management. In areas where reduction of nitrate in surface waters is imposed by legislation and regulatory measures, two catchments with different persistence properties may not respond to the same reduction of sources of nitrogen at the same rate.     

The effect of temperature on sensory quality,chemical composition and growth of carrots (Daucus carota L.). IL Constant diurnal temperatures under different seasonal light regimes

Summary

Carrots of cv. Panther F1 were grown in climate chambers at 9, 12, 15, 18 and 21°C, constant diurnal temperatures at three different periods of the year. The effect of varying solar radiation and temperatures were evaluated on growth, sensory attributes and chemical composition. Higher levels of light significantly increased most chemical and physical variables of the carrot roots. Temperature was the most important factor determining the variation in sensory and chemical variables, whereas for morphological features like root weight, root length and diameter measurements, light was more important than temperature. Principal component analysis (PCA) of chemical and physical variables explained 85% of the total variation by the first three principal components, the first component (PCI) being defined by physical variables, explained 46% of the variation, while the temperature related PC2 explained 32% of the variation. Prediction of sensory variables by chemical or physical variables by means of partial least square (PLS) was higher at low light intensity than at high light intensity.