Orchid bees respond to landscape composition differently depending on the multiscale approach

Landscape Ecology - Multiscale approaches are essential for understanding ecological processes and detecting the scale of effect. However, nested multiscale approaches retain the effect of the...     

Effects of rainfall,competition and grazing on flowering of Osteospermum sinuatum (Asteraceae) in arid Karoo rangeland

The shrub Osteospermum sinuatum, an important fodder plant in Karoo rangelands, flowered after heavy rain in autumn, winter and spring. The number of flowers produced per bush was positively conelated with basal stem diameter and rainfall in the 12 weeks before anthesis. Flowering increased when neighbouring plants of all species were removed. Grazing during flowering and seed set, by sheep stocked at recommended densities, reduced potential seed set by as much as 90%. Birds, hares and small antelope consumed 10–50% of the flowers. Size‐class distributions indicated that little recent recruitment had taken place on a ranch where palatable plants were scarce and where O. sinuatum flower production was severely depressed by grazing sheep.     

The control of the annual growth cycle in raspberry

Summary

The Brassicaceae (syn. Cruciferae) is an economically important botanical family providing a diverse range of foliar, root and seed crops for both human and domesticated animal consumption. However, in common with other plant species the Brassicacae have been endowed with the capacity to synthesize a range of antinutritional compounds, the most important of which are the glucosinolates, S-methylcysteine sulfoxide, tannins and erucic acid. In this review the adverse and possible beneficial effects of the inclusion of these compounds in human and animal diets are reviewed together with their chemistry, biosynthesis and methods for their analysis.     

Comparison of water‐retention functions obtained from the extended evaporation method and the standard methods sand/kaolin boxes and pressure plate extractor

Knowledge of the soil hydraulic functions is required for various hydrological studies and for the simulation of water and solute fluxes in unsaturated soils. Sand/kaolin boxes are frequently used to determine these properties in the low‐tension range. For higher tensions the pressure plate extractor is mainly applied. The extended evaporation method allows a more efficient determination of the water‐retention curve in an adequate range. Besides this method enables to quantify simultaneously the unsaturated hydraulic‐conductivity function. The objective of this study was to compare the water‐retention curves obtained from the standard methods (STM) with those determined with the extended evaporation method (EEM). A set of 90 natural soil samples of different texture and origin was analyzed, and the agreement between the methods was statistically evaluated. The average water‐content deviation (AWCD) of all samples was 1.83 vol.%, and the root mean square error (RMSE) 2.08 vol.%. The deviation of soil water‐storage capacity in the pore‐size classes 0–6, 6–30, 30–500, 500–1500 kPa varied between minimum –0.17 and 0.25 vol.% and maximum –2.89 and 2.36 vol.%, and confirmed the good comparability among the adopted methods. Systematic deviations between the methods were not found.     

Nitrogen and Phosphorus Remediation by Three Floating Aquatic Macrophytes in Greenhouse-Based Laboratory-Scale Subsurface Constructed Wetlands

In the greenhouse and container nursery production industry there is potential for runoff of nitrogen (N) and phosphorus (P), which may contaminate surface and groundwater. Since the 1950s constructed wetlands (CWs), as a simple, low-technology method, have been shown to effectively treat agricultural, industrial, and municipal wastewater. We investigated the N and P attenuating potential of three floating hydrophytes planted in a laboratory-scale subsurface flow (SSF) CW system. Over an 8-week period plants were supplied with N and P (0.39 to 36.81 mg·L^?1 N and 0.07 to 6.77 mg·L^?1 P) that spanned the rates detected in nursery runoff between the discharge and inflow locations of a commercial nursery currently employing CWs. Whole plant dry weight was positively correlated with N and P supplied. Highest N recovery rates were exhibited by water hyacinth (Eichhornia crassipes [Mart.] Solms.) and water lettuce (Pistia stratiotes L.). P recovery rates were similar for water hyacinth, water lettuce, and dwarf redstemmed parrotfeather (Myriophyllum aquaticum [Vell.] Verdc.). These floating hydrophytes can be cultivated in a SSF CW to remediate runoff losses of N and P. The possibility exists for integrating them into a polycultural remediation system that includes emergent aquatic macrophytes for processing and polishing nursery/greenhouse wastewater.     

Effects of topical administration of an aldose reductase inhibitor on cataract formation in dogs fed a diet high in galactose

OBJECTIVE: To determine effects of a topical formulation of an aldose reductase inhibitor (ARI) on the development of sugar cataracts in dogs fed a diet high in galactose. Animals-Ten 6-month old Beagles. PROCEDURES: Dogs were fed a diet containing 30% galactose, and after 16 weeks, 6 dogs were treated topically with a proprietary ARI formulation and 4 dogs were treated with a placebo. Cataract formation was monitored by means of slit-lamp biomicroscopy and fundus photography. Dogs were euthanized after 10 weeks of treatment, and lenses were evaluated for degree of opacity, myo-inositol and galactitol concentrations, and concentration of the ARI. RESULTS: All dogs developed bilateral cortical opacities dense enough to result in a decrease in the tapetal reflex after being fed the galactose-containing diet for 16 weeks. Administration of the ARI arrested further development of cataract formation. In contrast, cataracts in the vehicle-treated dogs progressed over the 10-week period to the mature stage. Evaluation of the isolated lenses after 26 weeks of galactose feeding indicated that lenses from treated dogs were significantly less optically dense than lenses from control dogs. Lenticular myo-inositol concentration was significantly higher in the treated than in the control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that topical application of a proprietary ARI formulation may arrest or reverse the development of sugar cataracts in dogs fed a diet high in galactose. This suggests that this ARI formulation may be beneficial in maintaining or improving functional vision in diabetic dogs with early lens opacities.     

High levels of pollen dispersal detected through paternity analysis from a continuous Symphonia globulifera population in the Brazilian Amazon

In this study, six highly polymorphic microsatellite loci and a categorical paternity analysis approach were used to investigate the contemporary pollen gene flow in the neotropical tree species Symphonia globulifera. Data for this study were taken from a 500 ha experimental plot in a dense terra firme forest in the Eastern Brazilian Amazon and included the mapping and genotyping of 161 reproductive trees, representing more than 90% of all adult trees, and the collection of 748 open-pollinated seeds from 56 seed-trees over two field seasons (2002 and 2003). High levels of pollen immigration from outside of the study plot were detected in both sampled seed-years (≥49%) suggesting long distance pollen gene flow. Low levels of self-fertilization were also detected (≤2%). The analysis showed long distance pollen dispersal occurred within the study area in both 2002 (δ = 907 ± 652 m SD) and 2003 (δ = 963 ± 542 m SD). Patterns of pollen dispersal distance within the plot were also found to be shorter than the distances between potential male parents and seed-trees. This result indicates that the distance between trees does not explain the identified pollen dispersal pattern. Our results support the hypothesis that animal pollinated species occurring in low-density populations can disperse pollen in long distances, despite the very dense nature of the forest.     

Assessment of the usage of biodegradable polymeric matrix in vaginal devices to sustain progesterone release in cows

The usage of timed artificial insemination (TAI) at a low cost leading to better reproductive rates has been the aim of several research groups in the field. Usually during TAI protocols, sustained progesterone (P₄) release devices are employed. Most devices are constituted of a nylon skeleton covered with a silicon layer with P₄. A device based on biopolymers was developed in order to reduce costs and decrease its environmental impact. In this study, we compared the kinetics of sustained progesterone release among devices manufactured with a polymeric blend made of polyhydroxybutyrate‐valerate (PHBV) and poly‐ε‐caprolactone (PCL) (DISP) which were compared with DIB® (Internal Bovine Device) used as the control. In the in vitro and in vivo progesterone release tests, two types of biopolymer‐based devices with a superficial area of 147 cm² were used: DISP8 (46% PHBV, 46% PCL and 8% P₄; n  = 4), DISP10 (45% PHBV, 45% PCL, 10% P₄; n  = 4) and DIB® (1 g P₄, 120 cm² area; n  = 3). The in vitro tests were carried out according to USP XXIII specifications and were performed in a dissolutor sink using an alcohol/water mixture (60/40 v/v) as a release media and samples were collected at 2 min, 2, 4, 8, 12, 24, 48, 60, 72, 84 and 96 h. P₄ concentrations were measured through spectrophotometry in a 244 nm long wave. Three to 3 comparisons of angular coefficients of the straight lines obtained by regression analysis of accumulated P₄ concentrations as a function of square root of time were carried out. Furthermore, the diffusion coefficient values of P₄ were also determined for DISP8 and DISP10. The results showed that the concentrations of P₄ were higher in the DISP10 (774.63 ± 45.26 μg/cm²/t^1/2) compared to DISP8 (566.17 ± 3.68 μg/cm²/t^1/2) (P  < 0.05). However, both DISP10 and DISP8 P₄ concentrations did not differ from DIB® (677.39 ± 16.13 μg/cm²/t^1/2). For the analysis of released quantities per day of the in vitro test, four periods were considered: 0–24, 24–48, 48–72 and 72–96 h. In the first 24 h, DISP8 released significantly less P₄ than DISP10 or DIB®, which did not differ among them. Between 24 and 48 h, DISP10 released significantly more P₄ than DIB®. DISP8 released an intermediate P₄ amount and did not differ significantly from DIB® or DISP10. Between 48 and 72 h, P₄ quantity released by DISP10 was significant higher (P  < 0.01) than that of DIB® and DISP8, which did not differ among themselves. Between 72 and 96 h, DISP10 released significantly more P₄ than DIB®, and DISP8 released an intermediate amount which did not differ from DIB® or DISP10 (P  < 0.01). There was interaction between treatment and time (P  = 0.0024). The diffusion coefficient values were: 1.36 × 10^?8 (cm²/s) for DISP10 and 1.12 × 10^?8 (cm²/s) for DISP8. For the in vivo test, ovariectomized crossbred cows received DIB® (n  = 4) or DISP8 (n  = 8) in an alternate design with a non‐balanced sequence (cross‐over) added of measures repeated in time referring to 16 days of blood samples collection. Samples were analyzed through radioimmunoassay in solid phase using the commercial kit of DPC (Diagnostics Products Corporation). Plasma concentrations of P₄ peaked at 4 h after the placement of the device, this being the only time in which plasma P₄ concentrations differed between DIB® (11.45 ± 1.96) compared with DISP8 (9.23 ± 1.15 ng/mL) (P  = 0.027). On day 8, plasma P₄ concentrations were similar for DIB® (2.44 ± 0.09) and DISP8 (1.89 ± 0.13 ng/mL) (P  = 0.58) showing that both devices were able to keep P₄ concentrations above 1 ng/mL in the plasma of the cow during the 16 day in vivo test. In conclusion, devices manufactured with the blend of PHBV/PCL biopolymers can sustain the release of P₄ in a similar manner as silicon.