Feasibility of ley-farming system performance in a semi-arid region using spatial analysis

In order to assess feasibility of ley farming system performance in the Aq-Qala township, a semi-arid region in north of Iran, Multi-Criteria Analysis (MCA) method and Geographic Information System (GIS) techniques were integrated to evaluate the suitability of wheat, barley and annual alfalfa cultivation. The agronomic and ecological requirements of three crops were identified from available scientific literatures. In this study, environmental variables were included: 1) average, minimum and maximum temperatures, 2) precipitation, 3) slope, 4) slope aspects, 5) elevation and 6) soil characteristics such as organic matter, pH, electrical conductivity (EC), texture, nitrogen, phosphorus, potassium, calcium, iron, and zinc. Weights of these variables were extracted from analysis of Analytical Hierarchy Process (AHP) questionnaires. The suitability analysis was based on matching between land qualities/characteristics and crop requirements. It was done by the weighted overlay technique (WOT) in GIS. In order to assess the land suitability of ley farming system performance, the digital suitability layers of three crops were overlaid and integrated in GIS media by raster calculator functions, then zoning of region was done in 4 classes, including: Highly suitable, moderately suitable, marginally suitable and non-suitable. Our results indicated that 35.1% (35495.20 ha) of total areas of studied region is suitable for ley farming system. According to the generated agricultural suitability map, it was determinate that 15.2% (20681.77 ha) of the region is non-suitable for ley-farming performance, 19.5% (23245.74 ha) is marginally suitable and, 30.2% (33725.60 ha) is moderately suitable. Highly suitable, moderately suitable and marginally suitable lands were expected to have a crop yield of 80–100%, 60–80% and 40–60% of the yield under optimal conditions with practicable and economic inputs, respectively. It was found that the most areas of the southern and central parts of Aq-Qala are the highly and moderately suitable regions. The results demonstrated that the high EC, low OM and low rainfall are the key limiting factors in non-suitable areas.     

Effect of infection by Metarhizium anisopliae (Hypocreales: Clavicipitaceae) on the feeding and oviposition of the pea leafminer Liriomyza huidobrensis (Diptera: Agromyzidae) on different host plants

The effect of fungal infection by Metarhizium anisopliae on feeding and oviposition of adult Liriomyza huidobrensis was examined on three host plants, faba bean (Vicia faba), French bean (Phaseolus vuklgaris) and snow pea (Pisum sativum) in the laboratory. Flies were contaminated with dry conidia and allowed to feed and oviposit on the different host plants. Mortality in L. huidobrensis varied between 14% and 20% in the controls and between 77% and 100% in fungal treatments 120 h post-infection for the three host plants. L. huidobrensis made more punctures (47.3–52.6 cm^?2) in the control than in the fungal treatments (23.1–26.9 cm^?2) for the three host plants. The cumulative average number of punctures cm^?2/female by L. huidobrensis was higher in the controls than in fungal treatments from 72 h post-treatment in faba bean (12.2 vs. 8.2) and French bean (14.8 vs. 8.9), and from 48 h post-inoculation in snow pea (8.5 vs. 5.7). Female L. huidobrensis laid more eggs in the control (0.6–6.1) than in fungal treatments (0.2–1.5) across the host plants tested. The cumulative mean number of eggs cm^?2/female was significantly higher in the controls than in fungal treatments from 48 h post-treatment in faba bean (0.4 vs. 0.2) and French bean (0.1 vs. 0), and 96 h post-inoculation in snow pea (0.2 vs. 0.1). The host plant did not affect the average total number of punctures but had a significant effect on egg laying, with faba bean harboring greater number of eggs in both control and fungal treatments. A proper timeline application of the fungus before onset of feeding and oviposition peaks will be crucial in field suppression of the pest using M. anisopliae. In addition, a great consideration must be given to the target host plants prior to application of the fungus.     

Identifying potential restoration areas of freshwater wetlands in a river delta

Identification of potential restoration areas is significant and important for implementing a sustainable restoration project and maintaining the ecosystem integrity. We established an eco-hydrological approach to identify potential restoration areas of freshwater wetlands that should and can be restored. Our eco-hydrological method identifies potential restoration areas from three dimensions, namely, transverse, longitudinal and vertical directions. Based on transfer matrix analysis between freshwater wetland and other land cover types and bird habitat suitability assessment, we identified the areas that should be restored under the 1989 and 2000 goals were 36,112 ha and 37,230 ha, respectively. Based on hydrological connectivity and balance between ecological water supply (EWS) and ecological water requirements (EWRs), the area can be restored under the 1989 and 2000 goals were 31,165 ha and 33,963 ha, respectively. The approach and results of this study can help in future restoration efforts in the Yellow River Delta and other similar coastal wetlands.     

Spatial modeling of deforestation processes in the Central Peruvian Amazon

This study examines the relation between primary forest loss and landscape characteristics in the Ucayali region, Peru. Seven variables (rivers, elevation, annual precipitation, soil suitability for agriculture, population density, paved roads, and unpaved roads), were identified as potential deforestation drivers. The variables were converted into spatially explicit layers of continuous data and divided into a 9 km² grid. A multiple regression analysis was conducted to determine variable significance. Distance to paved and unpaved roads were strongly associated with deforestation, followed by distance to rivers, annual precipitation and elevation. All significant variables were negatively correlated with deforestation. Variables excluded from the model were population density and soil suitability for agriculture, suggesting that the influence of population density on forest clearing across the study area was not significant, and that deforestation activities were undertaken regardless whether soils are suitable for agriculture or not. Based on the linear regression analysis, the significant variables were selected and added to the Land Change Modeler in order to project primary forest coverage by 2025. The modeling results predict extensive deforestation along the Aguaytia River and at the forest/non-forest interface along the paved highway. The rate of primary forest removal is expected to increase from 4783 ha y⁻¹ (for the 2007–2014 period) to 5086 ha y⁻¹ (for the 2015–2025 period). A preliminary survey questionnaire conducted to explore deforestation intentions by farmers in the region, partly confirmed the overall deforestation trends as projected by the model.     

Loss of aboveground forest biomass and landscape biomass variability in Missouri,US

Disturbance regimes and forests have changed over time in the eastern United States. We examined effects of historical disturbance (circa 1813 to 1850) compared to current disturbance (circa 2004 to 2008) on aboveground, live tree biomass (for trees with diameters ≥13 cm) and landscape variation of biomass in forests of the Ozarks and Plains landscapes in Missouri, USA. We simulated 10,000 one-hectare plots using random diameters generated from parameters of diameter distributions limited to diameters ≥13 cm and random densities generated from density estimates. Area-weighted mean biomass density (Mg/ha) for historical forests averaged 116 Mg/ha, ranging from 54 Mg/ha to 357 Mg/ha by small scale ecological subsections within Missouri landscapes. Area-weighted mean biomass density for current forests averaged 82 Mg/ha, ranging from 66 Mg/ha to 144 Mg/ha by ecological subsection for currently forested land. Biomass density of current forest was greater than historical biomass density for only 2 of 23 ecological subsections. Current carbon sequestration of 292 TgC on 7 million ha of forested land is less than half of the estimated historical total carbon sequestration of 693 TgC on 12 million ha. Cumulative tree cutting disturbances over time have produced forests that have less aboveground tree biomass and are uniform in biomass compared to estimates of historical biomass, which varied across Missouri landscapes. With continued relatively low rates of forest disturbance, current biomass per ha will likely increase to historical levels as the most competitive trees become larger in size and mean number of trees per ha decreases due to competition and self-thinning. Restoration of large diameter structure and forested extent of upland woodlands and floodplain forests could fulfill multiple conservation objectives, including carbon sequestration.     

Effect of different sewage sludge applications on growth and yield of Vigna radiata L. field crop: Metal uptake by plant

The aim of this study was to assess the suitability of sewage sludge use for mung bean {Vigna radiata L. cv. Malviya janpriya (HUM 6)} plants by evaluating the growth, and yield responses, nutritional quality and heavy metal accumulation at different sewage sludge amendment (SSA) rates. Sewage sludge amendment modified the physico-chemical properties of soil by decreasing pH and increasing organic carbon, total iron and heavy metals. Plants showed increments in shoot length, leaf area and total biomass at all SSA rates, but root length increased only up to 9 kg m^?2 SSA rates. Plants grown at different SSA rates showed higher nutrients and heavy metals in seeds, but protein content declined. Sewage sludge application caused about 39, 76 and 60% more yield at 6, 9 and 12 kg m^?2 treatments, respectively. Concentrations of Pb and Ni in grains were higher than the Indian permissible limits at and above 9 kg m^?2 and of Cd at 12 kg m^?2 SSA rates.The study suggests that SSA at a rate lower than 9 kg m^?2 may be recommended due to better fertilizing value for soil and promoting mung bean yield. Higher rate of sewage sludge application leads to elevated accumulation of heavy metals in seeds, which limits the suitability for human consumption.     

Ecology and evolution of Devonian trees in New York,USA

The first trees in New York were Middle Devonian (earliest Givetian) cladoxyls (?Duisbergia and Wattieza), with shallow-rooted manoxylic trunks. Cladoxyl trees in New York thus postdate their latest Emsian evolution in Spitzbergen. Progymnosperm trees (?Svalbardia and Callixylon–Archaeopteris) appeared in New York later (mid-Givetian) than progymnosperm trees from Spitzbergen (early Givetian). Associated paleosols are evidence that Wattieza formed intertidal to estuarine mangal and Callixylon formed dry riparian woodland. Also from paleosols comes evidence that Wattieza and Callixylon required about 350 mm more mean annual precipitation than plants of equivalent stature today, that Wattieza tolerated mean annual temperature 7 °C less than current limits of mangal (20 °C), and Callixylon could tolerate temperatures 14 °C less than modern mangal. Devonian mangal and riparian woodland spread into New York from wetter regions elsewhere during transient paleoclimatic spikes of very high CO₂ (3923 ± 238 ppmv), and subhumid (mean annual precipitation 730 ± 147 mm) conditions, which were more likely extrinsic atmospheric perturbations rather than consequences of tree evolution. For most of the Middle Devonian CO₂ was lower (2263 ± 238 ppmv), and paleoclimate in New York was semiarid (mean annual precipitation 484 ± 147 mm). Such transient perturbations and immigration events may explain the 40 million year gap between the late Emsian (400 Ma) evolution of trees and Famennian (360 Ma) CO₂ drawdown and expansion of ice caps.     

Dietary inclusion of raw faba bean instead of soybean meal and enzyme supplementation in laying hens: Effect on performance and egg quality

An experiment was conducted with 160 Hisex Brown laying hens to evaluate the effect of different inclusion levels of faba bean (FB) and enzyme supplementation on productive performance and egg quality parameters. The experimental diets consisted of five levels of FB: 0% (control), 25%, 50%, 75% and 100%, substituting soybean meal (SBM), and two levels of enzyme supplementation (0 or 250 mg/kg). Each dietary treatment was assigned to four replicate groups and the experiment lasted 22 weeks. A positive relationship (P < 0.05) was found between FB inclusion and body weight (BW) change of hens when compared to those of the control treatment. Enzyme supplementation significantly affected the final hens’ BW. Feed consumption (FC) of hens was statistically increased with increasing FB level up to 50%. Supplementing dietary enzyme mixture at 250 mg/kg led to improvement in FC at all studied ages (P < 0.05). Inclusion of 25% or 50% FB in diets had no adverse effects on feed conversion ratio (FCR) compared to the higher FB inclusion levels (75% or 100%). Egg weight (EW), egg number (EN) and egg mass (EM) were significantly (P < 0.05) influenced by FB inclusion in diet during the entire experimental periods, except for EN and EM at 20–24 weeks of age. Egg productive parameters were not influenced by enzyme mixture supplementation (P > 0.05). The main effect of FB levels replacing for SBM affected (P < 0.05) yolk and shell percentages, yolk index, yolk to albumen ratio, shell thickness and egg shape index. It can be concluded that FB and enzyme supplementation could be included in hens diet at less than 50% instead of SBM to support egg productive performance, however higher raw FB levels negatively affected egg production indices and quality.     

Weight gains of meat goat kids on wheat (Triticum aestivum L.) pastures fertilized at different nitrogen levels

Wheat (Triticum aestivum L.) pastures are increasingly being used for cool-season forages to complement range-based goat production systems in southern USA. Because goats are more selective than cattle, ideal nitrogen (N) fertilizer rates already established for wheat grazed by cattle may be different for goats. Weight gains of Boer X Spanish doe kids (average 17 kg) as well as forage yields and crude protein (CP), acid detergent fiber (ADF) and acid detergent lignin (ADL) concentrations were measured for two winter seasons on replicated wheat paddocks fertilized with 0, 56, 112 and 224 kg N/ha per season in split autumn/spring applications at Stephenville, TX, USA. Animals were stocked in the pasture at 20 head/ha from January to April 2003 (478 mm rainfall from September to March) and 2004 (355 mm rainfall). Available forage ranged from 50 to 200 kg/ha in January and from 2300 to 6300 kg/ha in April in the 0 and 224 kg N/ha paddocks, respectively. Crude protein dry matter (DM) concentration ranged from 25 to 34% (0 and 224 kg N/ha, respectively) in January, but down to 13 and 22% across treatments in April. Average daily gains (ADG) over the 90-day trial were similar both years, 68 g per head per day for the 0 N treatment and undifferentiated among the fertilized paddocks, all near 90 g per head per day. Results indicate that N fertilizer rates above 56 kg/ha per season do not increase ADG/kid, but will increase ADG/ha if stocking rates are adjusted for forage production.     

The influence of rapid urbanization and land use changes on terrestrial carbon sources/sinks in Guangzhou,China

Complex changes in carbon sources and sinks caused by rapid urbanization have been observed with extensive changes in the quantity, structure, and spatial pattern of land use types. Based on the modified Carnegie-Ames-Stanford Approach model and on gray relational analysis, we analyzed the influence of land use changes on carbon sinks and emissions in Guangzhou from 2000 to 2012. The aim was to identify suitable options for built-up land expansion that would allow for minimal carbon losses. The key results were as follows: (1) Built-up land increased by 118.91% in Guangzhou city over the study period, with this expansion taking the form of concentric circles extending around the old Yuexiu district. (2) Carbon emissions over the period of analysis significantly exceeded carbon sink capabilities. The total carbon sink decreased by 30.02%, from 535.40 × 10³ t to 374.6 × 10³ t. Total carbon emissions increased by 1.89 times, from 13.73 × 10⁶ t to 39.67 × 10⁶ t; 80% of carbon emissions were derived from energy consumption. (3) There were large differences in the extent of carbon sink losses at different scales of built-up land expansion and land use change. In Guangzhou, the loss of carbon sink is small when cultivated land (though not prime farmland) and water bodies are converted to built-up land on a small scale. The loss of carbon sink is much smaller when grasslands are converted to built-up land on a large scale. However, forested land, which has excellent carbon sink functions, should not be converted. (4) Changes in carbon sinks were mainly affected by natural factors and land urbanization. Changes in carbon emissions were mainly affected by population urbanization, economic urbanization, and land urbanization. (5) To achieve “economical and intensive use of land”, “urban growth boundary” and “ecological red lines” should be determined for government policies on land use management. These factors have great significance for “increasing carbon sinks and reducing carbon emissions” in urban ecological systems.     

Surface electromyographic measurements on land prior to and after 90 min of submersion (swimming) are highly reliable

The purpose of this study was to investigate the reliability of surface electromyography (sEMG) measurements after submersion (swimming) for 90 min. Isometric maximal voluntary contractions (MVC) on land and in water were collected from eight muscles on the right side of the body in 12 healthy participants (6 women and 6 men). Repeated measures analyses of variance (general linear model ANOVA) showed no significant differences in the peak amplitude MVC scores between land pre and post measurements for all muscles, p > .05. The mean of the Intraclass correlation coefficient (1, 1) for land pre and land post was .985 with (95% Cl = .978–.990), for land pre and water pre .976 (95% Cl = .964–.984) and for land pre and post, water pre and post .981 (95% Cl = .974–.987). Measuring sEMG on land before and after a prolonged submersion is highly reliable without additional waterproofing when using electrodes with 57 mm diameter.     

Influence of selected host plants on biology of castor whitefly,Trialeurodes ricini (Hemiptera: Aleyrodidae)

The development time, immature survivorship, immature size, tertiary sex ratio, pre-oviposition period, fecundity, and preferences of the castor whitefly, Trialeurodes ricini on four host plant species (castor, eggplant, cotton and green bean) were evaluated under laboratory conditions. Development time from egg to adult emergence was the longest on cotton (33.3 days), the shortest on green bean (25.4 days), and intermediate on eggplant (28.5 days) and castor (28.3 days). The survival rate was the highest on castor (92.5%), followed by those on green bean (80.2%) and eggplant (73.8%), and the lowest on cotton (42.6%). The sex ratio was the highest on cotton (♀:♂ = 2.45:1.00), the lowest on eggplant (♀:♂ = 0.75:1.00), and intermediate on castor and green bean (♀:♂ = 1.04:1.00). T. ricini immatures and adults were generally larger when reared on castor and eggplant than on other plants. The net reproduction rate (R₀) was 57.656 females per female per generation, the generation time (T) was 35.9 days, the intrinsic rate of increase (r_m) was 0.1128 eggs per female per day, the gross reproduction rate (GRR) was 108.04 eggs per female per generation, the finite rate of increase (λ) was 1.1194 females per female per day, and the doubling time (DT) was 6.1149 days. In both no-choice and two-choice tests, T. ricini adults preferred castor for feeding and oviposition.     

Impact of landscape pattern at multiple spatial scales on water quality: A case study in a typical urbanised watershed in China

Buffer zones along rivers and streams can provide water quality services by filtering nutrients, sediment and other contaminants from the surface. Redundancy analysis was used to determine the influence of the landscape pattern at the entire catchment scale and at multiple buffer zone scales (100 m, 300 m, 500 m, 1000 m and 1500 m) on the water quality in a highly urbanised watershed. Change-point analysis was further applied to estimate the specific locations along a gradient of landscape metric that result in a sudden change in the water quality variable. The landscape characteristics for 100 m buffer zones appeared to have a slightly greater influence on the water quality than the entire catchment. The patch density of urban land and the large patch index of water were recognised as the dominant variables influencing the water quality for a 100 m buffer zone. The result of change-point analysis indicated key interval values of the two landscape metrics within the 100 m buffer zone. When the patch density of urban land was >30–40 n/100 ha and the largest patch index of water was >2.5–3.5%, the watershed water quality appeared to be better protected.     

A high-performance liquid chromatography–mass spectrometry assay for quantitation of the tyrosine kinase inhibitor nilotinib in human plasma and serum

Nilotinib (AMN-107, Tasigna?) is a small-molecule inhibitor of BCR/ABL, approved for chronic myelogenous leukemia. We developed and validated, according to FDA-guidelines, an LC–MS assay for sensitive, accurate and precise quantitation of nilotinib in 0.2 mL human plasma or serum. After acetonitrile protein precipitation, separation is achieved with a hydro-Synergi column and a 0.1% formic acid in methanol/water-gradient. Detection uses electrospray, positive-mode ionization mass spectrometry. Between 5 (LLOQ) and 5000 ng/mL, accuracy (92.1–109.5%), intra-assay precision (2.5–7.8%), and inter-assay precision (0–5.6%)) were within FDA limits. We demonstrated the suitability of this assay by quantitating plasma concentrations of nilotinib in a healthy volunteer after oral administration of 400 mg nilotinib.     

Leaf non-structural carbohydrates regulated by plant functional groups and climate: Evidences from a tropical to cold-temperate forest transect

Non-structural carbohydrates (NSCs), e.g., glucose and starch, play important roles in metabolic processes of plants and represent important functional traits in plant's adaptation to external environment. To explore the variations in leaf NSCs among species and communities at a large scale and their influencing factors, we investigated the contents of leaf NSCs among 890 plant species in nine typical forests along the north–south transect of eastern China. The results showed that the contents of leaf soluble sugars, starch, and NSCs (sugars + starch) were highly variable among different plant species on the site scale, and their mean values for the 890 plant species were 45.7 mg g⁻¹, 47.5 mg g⁻¹, and 93.2 mg g⁻¹, respectively. All three metrics varied markedly across plant functional groups in the order of trees < shrubs < herbs. Weak latitudinal patterns of leaf soluble sugars, starch, and NSCs were observed from tropical to cold-temperate forests at the levels of species and plant functional groups. The contents of leaf soluble sugars, starch, and NSCs decreased with increasing temperature and precipitation which supports the growth limitation hypothesis at a large scale. In trees, leaf soluble sugars, starch, and NSCs increased with increasing photosynthetic active radiation (PAR); and were positively correlated with specific leaf area (SLA). The spatial patterns of leaf NSCs in forests along the north–south transect of eastern China and their relationships with temperature, precipitation, PAR, and SLA illustrate an important adaptation of plant communities to environmental changes at the continental scale.     

A novel thermostable GH5_7 β-mannanase from Bacillus pumilus GBSW19 and its application in manno-oligosaccharides (MOS) production

A novel thermostable mannanase from a newly isolated Bacillus pumilus GBSW19 has been identified, expressed, purified and characterized. The enzyme shows a structure comprising a 28 amino acid signal peptide, a glycoside hydrolase family 5 (GH5) catalytic domain and no carbohydrate-binding module. The recombinant mannanase has molecular weight of 45 kDa with an optimal pH around 6.5 and is stable in the range from pH 5–11. Meanwhile, the optimal temperature is around 65 °C, and it retains 50% relative activity at 60 °C for 12 h. In addition, the purified enzyme can be activated by several ions and organic solvents and is resistant to detergents. Bpman5 can efficiently convert locus bean gum to mainly M2, M3 and M5, and hydrolyze manno-oligosaccharides with a minimum DP of 3. Further exploration of the optimum condition using HPLC to prepare oligosaccharides from locust bean gum was obtained as 10 mg/ml locust bean gum incubated with 10 U/mg enzyme at 50 °C for 24 h. By using this enzyme, locust bean gum can be utilized to generate high value-added oligosaccharides with a DP of 2–6.     

Spatiotemporal modeling of watershed nutrient transport dynamics: Implications for eutrophication abatement

The main objective of this study was to quantify nutrient transport dynamics of a previously ungauged, temperate watershed (145 km²) surrounding a shallow eutrophic lake and discern lake response to external nutrient loading, based on soil water assessment tool (SWAT) and the Organization of Economic Cooperation and Development (OECD) empirical lake models, respectively. A SWAT model was used to simulate baseline nutrient dynamics after its calibration and validation against daily tributary flow, total dissolved phosphorus (TDP), total phosphorus (TP), and nitrate (NO₃) loads. On the watershed scale, median annual TDP, TP, and NO₃ losses were 0.4, 1.1, and 2.0 kg ha^− 1, respectively. The highest median annual TP and NO₃ losses were estimated at 3.7 and 7.7 kg ha^− 1 for pastureland and 1.7 and 3.8 kg ha^− 1 for cropland and mixed forests, respectively. Baseflow was the major nutrient transport pathway over a wide range of precipitation events (450 to 900 mm yr^− 1). Erosion was the predominant surface process exporting P across the watershed. Critical source areas (CSAs) of TP and NO₃ comprised 17% and 4% of the watershed, respectively. Annual mean TP, and mean and maximum chlorophyll content indicated a hyper-eutrophication risk for the lake. An external P load reduction by excess of 80% could be necessary to restore mesotrophy in the lake. Our results suggested that subsurface P transport should not be overlooked a priori when groundwater-dependent and extensively farmed watersheds are managed for eutrophication abatement.     

Three-phase partitioning of trypsin inhibitor from legume seeds

Three-phase partitioning (TPP) was used to isolate trypsin inhibitors from navy bean (NB), red kidney bean (RK) and adzuki bean (AZ) from the Royal Project Foundation in Thailand. The method was to mix the crude extract with solid ammonium sulfate (30% saturation, w/v) and tert-butanol (t-butanol) in order to obtain the three phases. The trypsin inhibitor was purified to 5-, 14- and 7-fold with 315%, 441% and 228% recovery for NB, RK and AZ, respectively. The SDS-PAGE showed the major inhibitor band with the molecular weights (MWs) of 132, 118 and 13 kDa for NB, RK and AZ, respectively. The fractions from NB and AZ showed higher pH stability compared to that of the RK, and they had the optimum pH ranges of 7–9. The highest relative inhibitory activity of the fractions of NB and RK were found at 50 °C, and all fractions were quite stable at 90 °C for 60 min of incubation. Increasing the concentration of salt (up to 3%, w/v) did not significantly decrease the inhibitory activity of all fractions (p > 0.05). The trypsin inhibitors from the three legumes were unable to inhibit the autolysis of Pacific whiting and arrowtooth flounder muscles.     

Comparison of the effects of cereal and legume proteinaceous seed extracts on α-amylase activity and development of the Sunn pest

The Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is a significant limiting factor in the production of wheat and barley in many areas of the world. In the current study, the effect of semi-purified proteinaceous extracts of seeds on digestive enzymes, and the growth and development of the Sunn pest were studied. The results showed that the purified α-amylase inhibitor from Triticum aestivum (type І) and rice semi-purified seed extract did not significantly affect the Sunn pest α-amylase activity. However, bean and cowpea seed extracts significantly affected α-amylase activity in vitro. For example, the bean seed extract at concentrations of 0.125 and 2.0 mg · mL^− 1 inhibited α-amylase activity of the pest by 15% and 45%, respectively, while the cowpea seed extract, at the same concentrations, inhibited α-amylase activity of the pest by 9% and 40%, respectively. Further, incorporation of the seed extracts into the insect diet showed that the rice seed extract did not affect insect development time, while bean and cowpea seed extracts at high concentrations (e.g., 3.0%) significantly affected nymphal development time and survivability (P > 0.05). These results show that semi-purified seed extracts affect α-amylase activity, developmental time, and survivability but not the adult weight of the Sunn pest.     

Windows of opportunity for Prosopis velutina seedling establishment and encroachment in a semiarid grassland

Large increases in the density of woody plants in former grasslands have been documented globally over the past two centuries. Prosopis velutina (velvet mesquite) has recently expanded on over 38 million ha in the grasslands of the American southwest.Mesquite establishment and expansion is potentially influenced by competitive interactions with grasses, particle size distribution (texture) of soil and changes in the amount and/or seasonality of precipitation, amongst other factors.To investigate the relative importance of precipitation seasonality, grass competition, and soil texture on mesquite seedling and establishment, we experimentally manipulated seasonality of precipitation across 72 1.5 m × 1.7 m plots that we planted with two grasses from contrasting functional groups (or left unvegetated) across two highly contrasting soil textures within a semi-desert grassland in Arizona, USA, wherein we followed the demography of 8640 planted mesquite seeds between 2002 and 2006. Up to 70% of the variance in seedling emergence was explained by soil water content, and seedling mortality was more dependent on summer than on winter precipitation.Mortality of less drought tolerant grasses after drought in coarse textured soils created conditions most favorable for seedling establishment, whereas lower rates of seedling establishment were observed in finer textured soils or in plots dominated by more drought tolerant grasses.We conclude that mesquite encroachment is episodic, based on discontinuous patterns of seedling establishment, favored on coarse textured soils and associated with unique conditions of high summer water availability when precipitation is not limiting and when competition from grasses is lowered.