Endangered segetal species in southern Italy: distribution,conservation status,trends, actions and ethnobotanical notes

Distribution, conservation status, trends, actions and ethnobotanical notes of segetal species growing in South Italy are presented and discussed. For the most threatened segetal species details and suggestions for their conservation are reported. Research work was made directly in the field for collecting samples and in the laboratory for checking several herbarium samples. To the best of our knowledges, a summary table of all species occurring in the field, of the investigated environments, and their ecological focus areas, is provided for the first time.     

Utilization of enzyme mixtures to retard bread crumb firming

The influence of enzyme mixtures containing amylase and lipase activities on straight dough bread staling was studied. Amylopectin retrogradation, crumb firming, amylose-lipid complexes, and dextrin production were analyzed in bread samples supplemented with two enzyme mixtures. The addition of enzyme mixtures to bread formula causes a beneficial effect on bread keeping properties and the formation of a more thermostable amylose-lipid complex than the one found in control bread. Amylopectin retrogradation was inhibited by the use of the enzyme; the effect was accompanied by reduced crumb-firming rates. The enzymatically generated water-soluble dextrins (maltose and DP3, DP4, DP5, and DP6 dextrins) are the most effective in preserving crumb softness during bread storage.     

The influence of soil pH on denitrification: progress towards the understanding of this interaction over the last 50 years

Results from the pioneering research on the interactions between pH and denitrification in soil from the 1950s to the present are reviewed, the changing perceptions of this complex relationship are discussed, and the current status of the subject is assessed. Facets of this relationship that are analysed in detail include the direct or indirect influence of pH on overall denitrification rates in soils, changes in the composition of gaseous products that depend on pH, methods for measuring the process, the concept of an optimum pH for denitrification, and the adaptation of microbial denitrifying communities to acidic environments. The main conclusions to be drawn are as follows. Total gaseous emissions to the atmosphere (N₂O, NO and N₂) have repeatedly been shown to be less in acidic than in neutral or slightly alkaline soils. This may be attributable to smaller amounts of organic carbon and mineral nitrogen available to the denitrifying population under acid conditions rather than a direct effect of low pH on denitrification enzymes. Numerous laboratory and field studies have demonstrated that the ratio N₂O:N₂ is increased when the pH of soils is reduced. The relation between soil pH and potential denitrification as determined by various incubation methods remains unclear, results being influenced both by original conditions in soil samples and by unknown changes during incubation. The concept of an optimum pH for denitrification has been frequently proposed, but such a term has little or no meaning without reference to specific attributes of the process.     

SE—Structures and Environment: Optimal Control Strategies for Carbon Dioxide Enrichment in Greenhouse Tomato Crops—Part 1: Using Pure Carbon Dioxide

Two optimal control strategies for carbon dioxide (CO₂) enrichment in greenhouse tomato crops have been developed. One uses pure CO₂ from a storage tank and the other uses CO₂ contained in the exhaust gases of boilers burning natural gas. The optimal strategies maximize the financial margin between crop value and the combined costs of the CO₂ used for enrichment and the natural gas used for heating. In this paper, the strategy for optimal control using pure CO₂ is presented and compared with strategies used by growers. The optimal strategy for enrichment with exhaust gas derived CO₂ is presented in an accompanying paper. Simulations show that at a cost of £0·09 kg⁻¹ for pure CO₂ and £0·10 m⁻³ for natural gas, the optimal enrichment strategy would increase the annual margin of crop value over CO₂ and heating costs by £4·6 m⁻² (27%) compared to a basic control strategy of enrichment to a concentration of 1000 v.p.m. (parts per million by volume) when ventilators are <5% open, otherwise enrichment to 350 v.p.m. The optimal CO₂ concentration was expressed as an algebraic function of solar radiation, wind speed and ventilator opening angle, and so enabled a quasi-optimal value to be obtained using variables measured by greenhouse environmental controllers. The quasi-optimal equation, with coefficients averaged from simulations over 4 years, gave an increased margin over the basic control strategy of £4·4 m⁻² (26%).     

Improved Storherr tube for assisted and sweep co-distillation cleanup of pesticides, polychlorinated biphenyls, and pentachlorophenol from animal fats

A procedure is presented for the simultaneous extraction from animal fat and quantitation of 15 pesticide residues, 4 polychlorinated biphenyl (PCB) formulations, and pentachlorophenol (PCP). Silanization of the Storherr tube packing reduces thermal decomposition and allows for residue recoveries in excess of 88% from pork, beef, chicken, sheep, and rabbit fat. This Storherr tube performs well in either the assisted distillation or sweep co-distillation mode of operation. Detection limits of 2-5 ppb for the pesticides and 10 ppb for the PCBs are readily attained.     

Modelling water flow through undisturbed soil cores using a transfer function model derived from 3HOH and Cl transport

Large undisturbed soil cores (20 cm diam. × 25–30 cm long) were irrigated at rates of 0.5–4 cm h^?1 with 0.005 M CaCl₂ solution labelled with ³HOH. The cores were used at varying initial water contents and flow in all cases was unsaturated. Breakthrough curves for Cl and ³HOH were markedly asymmetric and unlike those reported for columns of packed aggregates. The data could be satisfactorily described using a density distribution function of the logarithm of cumulative drainage D. The mean and standard deviation of In D were estimated by a curve-fitting procedure from Cl and ³HOH effluent concentrations in each core. The mean pore water velocity and fraction of the soil water that participated in solute transport (the mobile volume) were also calculated. The apparent velocity of Cl movement was always greater than that of ³HOH which suggested that the mobile volume involved in convective and diffusive transport of Cl was less than that for ³HOH. We suggest that Cl and ³HOH diffused at different rates out of flowing water films in a relatively few large conducting channels into essentially immobile water within the surrounding soil matrix. The difference in mobile volume for Cl and ³HOH was used to calculate the perimeter of voids in any horizontal cross-section of the soil through which water flowed, assuming a planar interface between the mobile and immobile water.     

Highly weathered soils in the east coast hinterland of Southern Africa with thick, humus-rich A1 horizons

Strongly weathered red and yellow soils with thick (490–900 mm) humic Al horizons (Haplohumox and Palchumults) derived from sandstones and basic igneous rocks, and occurring near the east coast of Southern Africa, are described and discussed in terms of their distribution, morphology, texture, mineralogy, chemistry, genesis and classification. The high organic matter content (2–5%C) of the Al contributes significantly to a high pH-dependent negative charge, probably to poorer crystallinity of goethite and kaolinite and to the transformation of haematite to goethite. Varying proportions of kaolinite and gibbsite reflect different soil ages within these old landscapes. The yellow colour of aluminous goethite, the main pedogenic iron oxide, is masked in the Al by organic matter and in red B2 horizons by haematite. Temperature may have influenced the broad pattern of occurrence of red and yellow B2 horizons. These soils need not, as previously suggested, have developed from the weathering products of an ancient laterite. Neither Soil Taxonomy nor the South African soil classification system accommodates the soils entirely satisfactorily and possible improvements to the latter are discussed.     

Bio-corrosion: A note on fungal solubilization of iron from stainless steels

Cultures of the fungus Penicillium italicum can extract Fe from powdered stainless steels, including highly corrosion-resistant alloys containing 11 to 13 % Ni. Physical contact of fungus with metal is unnecessary, but acidification alone fails to account for the phenomenon. Evidence from other sources suggests that fungal metabolites are involved.     

Phosphatase activity in earthworm faeces

Wormcasts of Allolobophora caliginosa have been shown to have higher phosphatase activity than occurs in uningested soil, resulting in an increase in inorganic P released by mineralization of organic P. This paper describes similar observations on organic wastes which may be used for vermiculture. Besides A. caliginosa, three species which will feed on dung or other organic substrates were investigated, Eisenia foetida, Dendrobaena veneta and Lumbricus rubellus. When cow dung was used as a substrate, background phosphatase activity was too high for the effects of earthworm activity to be detected and a culture medium was therefore developed from sterilized paper waste sludge with added phytin. Phosphatase activity, assayed by a modified Hoffman method, was higher in the presence of all four earthworm species than in controls. It showed two peaks in relation to pH, at 3–5 and 9–10. The former is attributed to microbial activity and the latter to microbial activity or earthworm alkaline phosphatase. After 1 month, cultures of paper waste sludge with phytin contained about twice as much water soluble P when worms were present than in their absence.