In vitro protein degradation of 38 sainfoin accessions and its relationship to tannin content by different assays

This study compared 38 sainfoin and 2 Lotus accessions to their respective tannin contents, N buffer solubility, and in vitro protein degradation. Tannin contents were measured by a protein precipitation method using either bovine serum albumin or Rubisco and by the colorimetric HCl/butanol method. Precipitation of bovine serum albumin and Rubisco was highly correlated (R(2) = 0.939). Correlations between the protein precipitation variants and the HCl/butanol method were relatively low (R(2) < 0.6). Protein degradation was measured at 4 h of incubation in an inhibited in vitro system and could not be explained by any of the tannin assays (R(2) < 0.03) and only partially by N buffer solubility (R(2) ≤ 0.433). Decisive factors other than the quantity of tannins or their ability to precipitate proteins must be considered. Resistance of soluble protein toward degradation can possibly be caused by tannin protein binding.     

Arsenic Concentration in Tobacco Leaves: A Study on Three Commercially Important Tobacco (Nicotiana tabacum L.) Types

In recent years, arsenic (As) has received increased attention as humans may be exposed to it through occupational and environmental exposure. Tobacco (Nicotiana tabacum L.) like other crops can uptake this element from the soil, which may lead to human exposure. Here, we report on a survey on arsenic in cured or processed tobacco leaves obtained from Africa, Asia, Europe, South and North America. A total of 1,431 leaf samples of flue-cured, burley, and Oriental tobaccos were obtained from various sampling locations during 2002 to 2004. Arsenic concentration in the samples averaged 0.4?±?0.6 μg g^?1 as determined by inductively coupled plasma-mass spectrometry. Recorded values from most samples showed that concentrations of arsenic were usually found at the lower end of the distribution. Significant differences were found among tobacco types, sampling locations, and crop years. Arsenic concentrations were rather low in the majority of regions investigated, which is compatible with data from the literature. However, sample size was small and sampling geographically restricted. Our results would need to be validated with a larger dataset.     

Centimetre-scale digital representations of terrain and impacts on depression storage and runoff

The microscale topography of a 20 × 10 m hillslope in a burned portion of Kootenay National Park, British Columbia, Canada was determined through laser scanning at a sub-centimetre scale. Digital terrain models (DTM) were developed for this hillslope at the 0.75 cm, 10 cm, 25 cm, 50 cm, 75 cm and 1 m scales. Random Roughness, Tortuosity and Mean Upslope Depression were computed for bare and vegetated surfaces created at each resolution to determine mean depression storage as a function of resolution. Results for these various roughness parameters and associated depression storage values are not found to change appreciably between the vegetated and bare surface DTMs, and moreover do not change notably with increasing grid cell resolution. Depression storage was also computed using a GIS-based method, the values of which are considered to be, at the highest resolution of 0.75 cm, the most realistic for comparative purposes. Mean depression storage using this latter approach decreases significantly with an increase in grid cell size, in contrast to the values based on Random Roughness which remain stable with increasing grid cell size. The generation of Hortonian overland flow was modelled at different scales using the GIS-derived DTMs. The values of depression storage for the various scales of DTM are demonstrated to have significant influences on overland flow generation. The scale of the DTM affects the changes over time between the proportion of water going into depression storage and that contributing to overland flow, with more water being retained as depression storage at a particular value of rainfall excess after infiltration for the smaller DTM scalings. When overland flow develops from a rising groundwater table in a simulation exercise, water depths are initially lower than the primary roughness elements on the land surface and water is relatively disconnected. As water depths increase, more integrated connections form.     

The use of lysimeter data for the test of two soil–water balance models: A case study

Two soil–water balance models were tested by a comparison of simulated with measured daily rates of actual evapotranspiration, soil water storage, groundwater recharge, and capillary rise. These rates were obtained from twelve weighable lysimeters with three different soils and two different lower boundary conditions for the time period from January 1, 1996 to December 31, 1998. In that period, grass vegetation was grown on all lysimeters. These lysimeters are located in Berlin‐Dahlem, Germany. One model calculated the soil water balance using the Richards equation. The other one used a capacitance approach. Both models used the same modified Penman formula for the estimation of potential evapotranspiration and the same simple empirical vegetation model for the calculation of transpiration, interception, and evaporation. The comparisons of simulated with measured model outputs were analyzed using the modeling‐efficiency index IA and the root mean squared error RMSE. At some lysimeters, the uncalibrated application of both models led to an underestimation of cumulative and annual rates of groundwater recharge and capillary rise, despite a good simulation quality in terms of IA and RMSE. A calibration of soil‐hydraulic and vegetation parameters such as maximum rooting depth resulted in a better fit between simulated and observed cumulative and annual rates of groundwater recharge and capillary rise, but in some cases also decreased the simulation quality of both models in terms of IA and RMSE. The results of this calibration indicated that, in addition to a precise determination of the soil water‐retention functions, vegetation parameters such as rooting depth should also be observed. Without such information, the rooting depth is a calibration parameter. However, in some cases, the uncalibrated application of both models also led to an acceptable fit between measured and simulated model outputs.     

Relationship Between Wheat (Triticum aestivum L.) Grain Hardness and Wet‐Milling Quality

Grain hardness variation has large effects on many different end‐use properties of wheat (Triticum aestivum). The Hardness (Ha) locus consisting of the Puroindoline a and b genes (Pina and Pinb) controls the majority of grain hardness variation. Starch production is a growing end‐use of wheat. The objective of this study was to estimate the differences in starch yield due to natural and transgenically conditioned grain hardness differences. To accomplish this goal, a small‐scale wet‐milling protocol was used to characterize the wet‐milling properties of two independent groups of isogenic materials varying in grain hardness and in Pin expression level. The first group of lines consisted of hard/soft near‐isogenic lines created in cultivars Falcon or Gamenya in which lines carried either the Pina‐D1a (functional) or the Pina‐D1b (null) alleles of Pina. The second group of lines consisted of Pina, Pinb, or Pina and Pinb overexpressing lines created in Hi‐Line, a hard red spring wheat. Soft near‐isogenic lines had higher starch extractability than the hard Pina null counterparts. This difference in starch extractability was more pronounced between Hi‐Line and its transgenic isolines, with highest levels of extractable starch observed in the transgenic isoline with intermediate grain texture. The results demonstrate that the Ha locus and puroindoline expression are both linked to wet‐milling starch yield and that selection for increased Ha function increases starch yield through the enhanced separation of starch granules and the protein matrix during wet milling.     

Relationship of Ethanol Yield to Agronomic and Seed Quality Characteristics of Small Grains

Production of fuel ethanol hinges on the availability of carbohydrate sources, with corn being the crop of choice in most areas. However, in some climatic regions, it is not feasible to grow adequate volumes of corn so other starch sources must be utilized. Here we examined various small grain crops commonly grown in the Northern Great Plains for suitability for ethanol production. Four cultivars each of the hexaploid wheat (Triticum aestivum L.) classes hard red spring (HRS), hard white spring (HWS), soft white spring (SWS), along with durum wheat (Triticum durum L.), and four spring barley (Hordeum vulgare L.) cultivars were grown in replicated plots in two environments in 2006. Agronomic and seed quality traits, along with starch content and ethanol yield over a period of 72 hr were measured on all cultivars. Agronomic yield was highest for the barley cultivars and lowest for HRS and HWS. Seed size was greatest for the durum and barley cultivars. The SWS group had the lowest protein content and the highest starch content. Starch content was highly correlated with final ethanol yield and the SWS group was highest in absolute ethanol yield. However, ethanol yield per hectare was highest for barley, with SWS ranking second, while the HRS and HWS groups had the lowest ethanol yields per hectare. The results indicate that selection for small grain ethanol yield should focus primarily upon agronomic yield at the expense of protein content. Traditional selection for high HRS and HWS milling and baking quality is not consistent with maximal ethanol yield per hectare.     

Factors affecting the caffeine and polyphenol contents of black and green tea infusions.

The effects of product and preparation variables on the in-cup chemical composition of tea extracts is of interest because the appearance and taste characteristics and the possible health effects of a tea liquor arise from the chemical components extracted from the leaf during tea preparation. A comprehensive study was therefore undertaken to determine the contributions of product and preparation variables on the total soluble solids, caffeine, and polyphenol contents of tea extracts. The results of this study show that the variety, growing environment, manufacturing conditions, and grade (particle size) of the tea leaves each influence the tea leaf and final infusion compositions. In addition, the composition of the tea infusion was shown to be influenced by whether the tea was contained in a teabag and, if so, the size and material of construction of the bag. Finally, the preparation method, including the amounts of tea and water used, infusion time, and amount of agitation, was shown to be a major determinant of the component concentrations of tea beverages as consumed. An illustration of the variation introduced by these product and preparation factors is provided by comparing solids, caffeine, and polyphenol contents of green and black tea infusions when commercial products are prepared according to the instructions given on their packaging.     

Long-Term Base Cation Balances of Forest Mineral Soils in Finland

Long-term base cation balances (Ca, Mg and K) for forest mineral soils in Finland were calculated with mass balance methods. The aim of the study was to identify the areas in which weathering and base cation deposition do not support leaching and uptake of base cations by vegetation. The effect of stem harvesting and whole-tree harvesting on the base cation balances was studied and preliminary calculations were made about the amounts of ash needed for compensation of the potential base cation depletion. The effect of sulphur emission reduction till 2010 was also considered. The study demonstrated that there would be depletion of base cations in forest mineral soils in southern, central and northeastern Finland (40–50% of the grids) in the long term if whole-tree harvesting would be practised. Theoretical calculations showed that ash application would be most useful in those areas to compensate the base cation depletion. If stem harvesting is practised, only small areas (20%) in southwestern and southeastern Finland and northeastern Lapland would show depletion of base cations in the long term.