Surface energy balance model of transpiration from variable canopy cover and evaporation from residue-covered or bare-soil systems

A surface energy balance model based on the Shuttleworth and Wallace (Q J R Meteorol Soc 111:839–855, 1985) and Choudhury and Monteith (Q J R Meteorol Soc 114:373–398, 1988) methods was developed to estimate evaporation from soil and crop residue, and transpiration from crop canopies. The model describes the energy balance and flux resistances for vegetated and residue-covered surfaces. The model estimates latent, sensible and soil heat fluxes to provide a method to partition evapotranspiration (ET) into soil/residue evaporation and plant transpiration. This facilitates estimates of the effect of residue on ET and consequently on water balance studies, and allows for simulation of ET during periods of crop dormancy. ET estimated with the model agreed favorably with eddy covariance flux measurements from an irrigated maize field and accurately simulated diurnal variations and hourly amounts of ET during periods with a range of crop canopy covers. For hourly estimations, the root mean square error was 41.4 W m⁻², the mean absolute error was 29.9 W m⁻², the Nash–Sutcliffe coefficient was 0.92 and the index of agreement was 0.97.     

Economics of Flexible Versus Conservative Stocking Strategies to Manage Climate Variability Risk

Recommended strategies for dealing with drought include maintaining a conservative stocking rate, maintaining grazing flexibility by having yearlings as one of multiple enterprises on the ranch, and leaving a significant amount of herbaceous production at the end of the grazing season. We perform an economic analysis of these grazing strategies using a bio-economic multiperiod linear programming model with variable annual forage production and beef prices. We evaluate the economics of conservative versus flexible grazing where stock numbers are adjusted to match forage conditions. The deterministic model estimates that a flexible grazing strategy could nearly double net returns relative to a conservative strategy, but realizing this substantial economic potential means higher production costs, and it depends on a quality climate forecast that is not currently available. Maintaining grazing flexibility was determined to be very important for managing variable forage conditions, and its importance increased with the level of variability. Without annual variation in forage production, over 80% of available forage would optimally be allocated to cow–calf production. As forage variability increased to levels observed on the arid rangelands of the western United States, a 50:50 forage allocation between cow–calf and yearling enterprises was found to be optimal, but optimal cow numbers decreased over time as dry conditions force herd reductions. As compared to a cow–calf ranch only, adding flexible yearling enterprises increased average annual net ranch returns by 14% with conservative stocking and by up to 66% with flexible grazing. Herd expansion beyond a conservative level should occur with yearlings because adjusting cow numbers is too expensive relative to the potential short-term gain, even if forage conditions are known with certainty.     

Berries: Improving Human Health and Healthy Aging, and Promoting Quality Life—A Review

The importance of the diet in relation to human health has increased the interest of consumers on nutraceuticals rich foods, and especially on fruits and vegetables. Berries are rich sources of a wide variety of antioxidant phenolics; these phytochemicals include flavonoids, stilbenes, tannins, and phenolic acids. Reactive oxidant species and free radicals are produced in an extensive range of physiological processes. In addition to the antioxidant defenses produced in the body, there are exogenous sources supplied by the diet; this is the case of berry fruits, among others. The insufficiency of antioxidant defense mechanisms is associated to the pathology of chronic disorders such as cardiovascular diseases, inflammation, and diabetes. Therefore, the enforcement of the latter mechanisms is of the utmost importance. The isolation and characterization of compounds that may delay the onset of aging is receiving intense research attention; some berry phenolics are being associated with this functional performance. Berry phenolics may also act as antimicrobials which may be of help in the control of the wild spectra of pathogens, in view of recent problems associated with antibiotic resistance. Most of the research works on the antioxidant activity of bioactive constituents of berries has been carried out using in vitro assays. In view of this, the human studies investigating the bioavailability and potential toxicity of phenolics are receiving more attention. Finally, we would like to emphasize the necessity of associating new plant breeding and genetic studies of berries with the expression and overexpression of compounds for human health and healthy aging.     

Attract‐and‐kill: a new strategy for the management of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) in potato: laboratory experiments towards optimising pheromone and insecticide concentration

BACKGROUND: Sex pheromones of the potato tuber moths Phthorimaea operculella (Zeller) and Symmetrischema tangolias (Gyen) are ideal tools to monitor pest flight activity but are not used as means of control. The aim of the present study was to test the suitability of an attract‐and‐kill strategy consisting of pure pheromones and the contact insecticide cyfluthrin as the active ingredient, formulated with plant oils and ultraviolet absorbers, and applied in droplet sizes of 100 µL. RESULTS: Cyfluthrin at a concentration of 5 g L^?1 resulted in the highest and fastest killing of males after 48 h, with a 100% mortality after 3–4 days. In contrast, control males survived for 13 days. In olfactometer experiments, the pheromone concentration of 0.5 g L^?1 was significantly most attractive against eight virgin females. At controlled conditions (20 °C), no reduction in efficacy of the attract‐and‐kill formulation was observed for a minimum period of 36 days, whereas under natural environmental conditions the efficacy reduced gradually after day 6 of exposure. The longer the droplet was exposed, the longer was the time to reach 100% mortality of males. CONCLUSIONS: Compared with attract‐and‐kill studies for other pest species, the results are promising as a means of achieving highly effective control of potato tuber moths under field conditions. Copyright © 2010 Society of Chemical Industry     

Physicochemical,Nutritional and Antibacterial Characteristics of the Fruit of <Emphasis Type="Italic">Bromelia pinguin</Emphasis> L.

Bromelia pinguin L. is a plant native to Sinaloa, Mexico, where its fruit is used as food or as a phytotherapeutic agent. The fruits of B. pinguin were characterized and they could be considered as a functional food. These fruits show an average weight of 13.7 g and a yellow color of high luminosity (b* = 43.2, L* = 74.5). The values for acidity (4.6%, as citric acid) and pH (3.7) of B. pinguin fruit are similar to those of citrics. The edible portion is characterized by a high content of vitamin C (126 mg/100 g), ash (10.6 g/100 g d.w.), crude fiber (3.4 g/100 g d.w.), calcium (1290 mg/100 g d.w.), magnesium (500 mg/100 g d.w.), manganese (2.95 mg/100 g d.w.) and it is a good source of zinc (2.8 mg/100 g d.w.). Polar fractions extracted from the pulp fruit showed activity against several genera of human pathogenic-bacteria (Staphylococcus, Streptococcus, Enterococcus, Salmonella, Shigella, Escherichia and Pseudomonas).     

Seed morphology and cytogenetic characterization of an endangered wild cotton,Gossypium turneri Fryxell,from Mexico

Cotton (genus Gossypium) is an important agricultural crop around the world because of its fiber. Gossypium turneri Fryxell is a wild cotton species endemic to the state of Sonora (northwestern Mexico), whose status has been recently raised to endangered in the IUCN Red List. This species has invaluable characteristics that could be useful in the cultivated cotton gene pool. Despite its importance, G. turneri has been studied very little. To the best of our knowledge, no previous study has characterized its seed morphology and cytogenetics. Therefore, in the present study the seed morphology and karyotype of G. turneri were analyzed. Seeds of G. turneri have nonuniform oval shape and brown-gray color. This species produces short fibers attached to its seed surface that are not long enough for commercial use. Our seed sizes were greater than those previously described for G. turneri and other diploid cottons. The length and width of seeds were 8.80 mm and 4.83 mm, respectively. Traits such as embryo and seed coat were measured and carefully observed, and gossypol glands were observed only in the embryo during the evaluation of internal features of seeds. Cytogenetic analysis revealed 26 chromosomes (2n?=?2x?=?26) in mitotic cells of G. turneri. The karyotype analysis showed mainly metacentric (m), submetacentric (sm) and subtelocentric (st) chromosomes. Our results reveal important biological traits of G. turneri that could be considered in future studies to improve cultivated cotton.

     

The Consumption of <Emphasis Type="Italic">Hibiscus sabdariffa</Emphasis> Dried Calyx Ethanolic Extract Reduced Lipid Profile in Rats

The scientific basis for the statement that plants and their active constituents play an important role in the prevention of chronic and degenerative diseases is continously advancing. The object of the present study was to evaluate the effect of Hibiscus sabdariffa L. dried calyx ethanolic extract on the serum lipid profile of Sprague-Dawley rats. The rats were fed during 4 weeks with either a basal diet, containing high cholesterol (1%), cholic acid (0.25%), lard oil (10%), or a supplemental diet with H. sabdariffa extract at 5%, 10%, and 15% levels (SD₅, SD₁₀, SD₁₅). Weight gain and faeces dry weight were both very significantly less (p ≤ 0.01) in SD₁₀ and SD₁₅ groups as compared to the control group, as was food efficiency in SD₁₅. In the case of SD₁₀, food efficiency was only significantly lower (p ≤ 0.05). Faeces dry weight in SD₅ however, was the only one found to be significantly higher (p ≤ 0.05). Triacylglycerols and LDL levels were both significantly less (p ≤ 0.05) in all groups (SD₅, SD₁₀, and SD₁₅) as compared to the control. For total lipids, SD₁₀ and SD₁₅ showed significantly lower levels (p ≤ 0.05), whereas very significant differences (p ≤ 0.01) were observed in the case of SD₅. All groups had lower cholesterol levels compared to controls; however, only the SD₅ group was statistically significant (p ≤ 0.05). No significant results were found in any group in the cases of either phospholipid or HDL levels. A hypothesis of hibiscus acid racemization, (+)-HCA to (−)-HCA, mediated by intestinal flora enzymes possibly explains the significant triacylglycerol decrease in all experimental groups. VLDL, the precursor of LDL, is composed predominantly of triacylglycerols, suggesting that the significant decrease in LDL is related to observed triacylglycerol synthesis inhibition. Five percent H. sabdariffa extract addition showed the best results in the reduction of serum lipids under study conditions.     

Purification, crystallization, and preliminary X-ray characterization of a 36 kDa amaranth globulin.

The purpose of this study was to purify, crystallize, and characterize by X-ray diffraction an amaranth globulin for its subsequent structure elucidation. A 36-kDa amaranth globulin was extracted by sequential precipitation and purified by gel filtration and cationic exchange columns. It was crystallized at 18 degrees C from 4 M sodium formate. Suitable crystals for X-ray analysis were found to belong to the tetragonal crystal system with cell dimensions of a = b = 195.5 A and c = 164.14 A. Two possible tetragonal space groups P4(1)2(1)2 or P4(3)2(1)2 were determined. The crystals diffracted up to 2.5 A.