Spatial imaging reveals the pathways of Zn transport and accumulation during reproductive growth stage in almond plants.

The reproductive processes of several deciduous trees are highly sensitive to Zn deficiency. An understanding of the patterns of Zn storage and remobilization during bud development and bud break is critical for the development of fertilization strategies to prevent deficiencies and may be valuable in selection and breeding programs to develop more Zn-resilient cultivars. In this study, we provide insights into the in situ distribution of Zn in almond reproductive organs at tissue, cellular, and subcellular scales using synchrotron-based X-ray fluorescence. The concentrations of Zn in different parts of the vegetative and reproductive tissues were also analysed. Our results show that the small branches subtending the flower and fruit, pollen grain, transmitting tissues of styles, and seed embryo are all important storage sites for Zn. An increase in Zn concentrations in almond reproductive organs mostly occur during the expanding growth phase, such as bud-flush and the mid-fruit enlargement stage; however, Zn transport to floral parts and fruit tissues was restricted at the pedicel and seed coat, suggesting a bottleneck in the export of Zn from the mother plant to filial tissues. Our results provide direct visual evidence for in-situ Zn distribution within the reproductive tissues of a deciduous tree species.

Correlation between water stress and phenolic compounds of hydroSOStainable almonds.

BACKGROUND: Water scarcity is currently affecting many areas of the world, reaching worrying levels in drought areas such as southern Spain. To cope with this issue, researchers in the agricultural sector have implemented deficit irrigation strategies intended to reduce water consumption by increasing fruit quality. Almond is among the most popular tree nuts worldwide and also the most nut cultivated in Spain. Almond consumption, together with other nuts, has been widely associated with improvements in cardiovascular health, metabolic syndrome and diabetes owing to their bioactive compounds such as polyphenols. Water deficit strategies generate hydroSOStainable almonds, raised under water stress conditions, with high content of bioactive compounds. The aim of this work was to study the relationship between water stress, color and polyphenols in hydroSOStainable almonds. For this, instrumental color, total phenolic content and phenolic compounds were measured and correlated using Pearson's correlation. RESULTS: The results showed a strong relationship between water stress, color and polyphenols of almonds, showing that increasing water stress in plants up to ~100 MPa × day values of stress integral increase the polyphenols in almonds, leading to a reddish color. CONCLUSION: Finally, this research demonstrated that implementing water-saving strategies help to improve the phenolic content and color of hydroSOStainable almonds and also that isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside and kaempferol-3-O-glucoside could be important markers of hydroSOStainable almonds (cv. Vairo). Besides, hydroSOStainable almonds could be an important source of phenols, providing 25% of the estimated total polyphenolic daily intake. © 2020 Society of Chemical Industry.

Chemical and sensorial characterization of spray dried hydroSOStainable almond milk.

BACKGROUND: Water scarcity is a worldwide problem that leads to environmental and economic issues. Agriculture is one of the main consumers of water for irrigation and fertilization and almond is the major tree nut crop in the Mediterranean area. Furthermore, there is a continuous growing demand for healthy, vegan and sustainable products. Consequently, the present study aimed to chemically characterize almond milk powder enriched with probiotics manufactured from hydroSOStainable almonds (i.e. generated under water stress conditions). Almond milk powder enriched with probiotic bacteria was produced with almonds grown under optimal irrigation conditions (100% of the crop evapotranspiration) and was chemically compared to the samples made from hydroSOStainable almonds. Antioxidant activity, total phenolic content (TPC), minerals, organic acids and sugars, fatty acids, and descriptive sensory analysis were evaluated. RESULTS: The results showed that almond milk powder produced from hydroSOStainable almonds had a higher content of TPC, polyunsaturated fatty acids (PUFAs), PUFAs/saturated fatty acids (SFAs) ratio and PUFAs/monounsaturated fatty acids ratio, as well as almond and nutty flavors. Moderate and sustained deficit irrigation leads to powders with a higher content of PUFAs and PUFAs/SFAs ratio, which are parameters of utmost importance for health. CONCLUSION: Using these strategies, between 66% and 76% of the irrigation water can be saved, producing hydroSOStainable almond milk powder higher in TPC and PUFAs, as well as positive sensory attributes, compared to that from fully irrigated almonds. These findings may have a positive impact in both agriculture and food industry, allowing water savings and high quality and sustainable food products to be obtained. © 2020 Society of Chemical Industry.

Transcriptome profiling of fully open flowers in a frost-tolerant almond genotype in response to freezing stress.

Spring frost is a major limiting abiotic stress for the cultivation of almonds [Prunus dulcis (Mill.)] in Mediterranean areas or the Middle East. Spring frost, in particular, damages almond fully open flowers, resulting to significant reduction in yield. Little is known about the genetic factors expressed after frost stress in Prunus spp. as well as in almond fully open flowers. Here, we provide the molecular signature of pistils of fully open flowers from a frost-tolerant almond genotype. The level of frost tolerance in this genotype was determined for all three flowering stages and was confirmed by comparing it to two other cultivars using several physiological analyses. Afterwards, comprehensive expression profiling of genes expressed in fully open flowers was performed after being exposed to frost temperatures (during post-thaw period). Clean reads, 27,104,070 and 32,730,772, were obtained for non-frost-treated and frost-treated (FT) libraries, respectively. A total of 62.24 Mb was assembled, generating 50,896 unigenes and 66,906 transcripts. Therefore, 863 upregulated genes and 555 downregulated genes were identified in the FT library. Functional annotation showed that most of the upregulated genes were related to various biological processes involved in responding to abiotic stress. For the first time, a highly expressed cold-shock protein was identified in the reproductive organ of fruit trees. The expression of six genes was validated by RT-PCR. As the first comprehensive analysis of open flowers in a frost-tolerant almond genotype, this study represents a key step toward the molecular breeding of fruit tree species for frost tolerance.

Evaluation of the chemical and nutritional characteristics of almonds (Prunus dulcis (Mill). D.A. Webb) as influenced by harvest time and cultivar.

BACKGROUND: Several workers have studied the effect of harvest time on chemical and nutritional composition of almonds, but the results are partly conflicting, probably due to differences in the cultivars considered and to different agronomic and climatic conditions in the growing areas. In this paper, the influence of harvest time and cultivar on the chemical and nutritional composition of almonds (Prunus dulcis (Mill). D.A. Webb) were evaluated. Ten cultivars were considered, grown in the same orchard and subjected to the same agronomical regime. Almonds were collected at two different harvest times: (i) when the fruits were unripe, but already edible, and showed green and moist hull; and (ii) when the fruits were ripe, with dry brown hull. The analyses of proximate composition, fatty acid profile, total phenolic compounds, and antioxidant activity were carried out. RESULTS: Lipid content increased (P < 0.001) during ripening, while both protein and carbohydrate content decreased (P < 0.01). Fatty acid composition showed a not univocal behavior during ripening and was highly influenced by cultivar. Total phenolic compounds and antioxidant activity varied among cultivars but increased during ripening with the exception of cv Marcona. The 'Genco' and 'Francolì' cultivars were found to be phenolic rich. CONCLUSION: Harvest time and cultivar significantly influenced the chemical and nutritional composition of almonds. Genotype strongly influenced fatty acid composition and total phenolic compounds. The changes of bioactive compounds and antioxidant activity suggest that the synthesis of antioxidants also occurs in the last stage of ripening. Unripe almonds, a valuable niche product, showed interesting nutritional value. © 2018 Society of Chemical Industry.

Comparing mechanistic and empirical approaches to modeling the thermal niche of almond.

Delineating locations that are thermally viable for cultivating high-value crops can help to guide land use planning, agronomics, and water management. Three modeling approaches were used to identify the potential distribution and key thermal constraints on on almond cultivation across the southwestern United States (US), including two empirical species distribution models (SDMs)-one using commonly used bioclimatic variables (traditional SDM) and the other using more physiologically relevant climate variables (nontraditional SDM)-and a mechanistic model (MM) developed using published thermal limitations from field studies. While models showed comparable results over the majority of the domain, including over existing croplands with high almond density, the MM suggested the greatest potential for the geographic expansion of almond cultivation, with frost susceptibility and insufficient heat accumulation being the primary thermal constraints in the southwestern US. The traditional SDM over-predicted almond suitability in locations shown by the MM to be limited by frost, whereas the nontraditional SDM showed greater agreement with the MM in these locations, indicating that incorporating physiologically relevant variables in SDMs can improve predictions. Finally, opportunities for geographic expansion of almond cultivation under current climatic conditions in the region may be limited, suggesting that increasing production may rely on agronomical advances and densifying current almond plantations in existing locations.

Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees.

Few studies have focused on the characterization of bud dormancy and growth dynamics for temperate fruit species in temperate and mild cropping areas, although this is an appropriate framework to anticipate phenology adaptation facing future warming contexts which would potentially combine chill declines and heat increases. To examine this issue, two experimental approaches and field observations were used for high- and low-chill apple cultivars in temperate climate of southern France and in mild climates of northern Morocco and southern Brazil. Low-chill almond cultivars offered an additional relevant plant material for comparison with apple in northern Morocco. Divergent patterns of dormancy and growth dynamics were clearly found in apple tree between southern France and southern Brazil. Divergences were less pronounced between France and Morocco. A global view outlined main differences in the dormancy chronology and intensity, the transition between endordormancy and ecodormancy and the duration of ecodormancy. A key role of bud rehydration in the transition period was shown. High-chill cultivars would be submitted in mild conditions to heterogeneous rehydration capacities linked to insufficient chill fulfillment and excessive forcing linked to high temperatures. This would favor bud competitions and consequently excessive flowering durations and weak flowering. Low chilling requirements in apple and almond would conversely confer biological capacities to tolerate superficial dormancy and abrupt transition from endordormancy to ecodormancy without important heterogeneous rehydration states within buds. It may also assume that low-chill cultivars can also tolerate high temperatures during ecodormancy as well as extended flowering durations.

Dietary Almonds Increase Serum HDL Cholesterol in Coronary Artery Disease Patients in a Randomized Controlled Trial.

BACKGROUND: More than one-half of coronary artery disease (CAD) patients have low HDL cholesterol despite having well-managed LDL cholesterol. Almond supplementation has not been shown to elevate circulating HDL cholesterol concentrations in clinical trials, perhaps because the baseline HDL cholesterol of trial subjects was not low. OBJECTIVE: This clinical trial was designed to test the effect of almond supplementation on low HDL cholesterol in CAD patients. METHODS: A total of 150 CAD patients (50 per group), with serum LDL cholesterol ≤100 mg/dL and HDL cholesterol ≤40 mg/dL in men and ≤50 mg/dL in women, were recruited from the Aga Khan University Hospital. After recording vital signs and completing a dietary and physical activity questionnaire, patients were randomly assigned to 1 of the following 3 groups: the no-intervention group (NI), the Pakistani almonds group (PA), and the American almonds group (AA). The respective almond varieties (10 g/d) were given to patients with instructions to soak them overnight, remove the skin, and eat them before breakfast. Blood samples for lipid profiling, body weight, and blood pressure were collected, and assessment of dietary patterns was done at baseline, week 6, and week 12. RESULTS: Almonds significantly increased HDL cholesterol. At weeks 6 and 12, HDL cholesterol was 12-14% and 14-16% higher, respectively, in the PA and AA than their respective baselines. In line with previous reports, serum concentrations of total cholesterol, triglycerides, LDL cholesterol, and VLDL cholesterol; total-to-HDL and LDL-to-HDL cholesterol ratios, and the atherogenic index were reduced in both the PA and AA at weeks 6 and 12 compared with baseline (P < 0.05). Effects on serum lipids did not differ between the 2 almond groups. Dietary patterns, body weight, and blood pressure did not change in any of the 3 groups during the trial. CONCLUSION: A low dose of almonds (10 g/d) consumed before breakfast can increase HDL cholesterol, in addition to improving other markers of abnormal lipid metabolism in CAD patients with low initial HDL cholesterol. This trial was registered at the Australian New Zealand Clinical Trial Registry as ACTRN12614000036617.

Bacterial populations on the surfaces of organic and conventionally grown almond drupes.

AIMS: To compare the bacterial populations on organically and conventionally grown almond drupes before and after hull split. METHODS AND RESULTS: We constructed 16S rRNA gene libraries, containing approx. 3000 sequences each, from the bacteria from organically and conventionally grown drupes before and after hull split. We observed that before hull split both conventionally and organically grown drupes were colonized by relatively few types of bacteria that were mostly common phyllosphere-associated Proteobacteria. However, the organically grown drupes contained significantly more Alphaproteobacteria and the conventionally grown drupes contained significantly more Gammaproteobacteria. The conventionally grown drupes also contained significantly more sequences associated with the phylum Actinobacteria. After hull split, we observed a significant increase in bacterial diversity, with many newly appearing sequences that were not normally associated with the phyllosphere. CONCLUSIONS: Organic and conventional growing methodologies influence the types of bacteria on almond drupes and hull split results in a burst of microbial diversification. SIGNIFICANCE AND IMPACT OF THE STUDY: Production of organic produce is increasing due to consumer preferences, but it was unknown how this methodology affects the bacterial populations on almond drupes. This is the first study to compare the bacterial populations of organically and conventionally grown almond drupes.

How does water stress affect the low molecular weight phenolics of hydroSOStainable almonds?

Water scarcity is a threat for food production because, water, is more and more limited and force farmers to use new deficit irrigation (DI) strategies without affecting fruit yield and quality. No information exists on almond polyphenols and proanthocyanidins (PAs) produced under DI. The present work studied the effect of 2 regulated DI (RDI) and one sustained (SDI) on the low molecular weight phenolics together with the antioxidant activity (AA) in almonds. Fifteen phenolic compounds were identified (13 flavonoids and 2 non-flavonoids) and 10 PAs. Kaempferol-3-O-galactoside was the predominant compound in almond skin and whole kernel but it was not found in deskinned kernels. The use of moderate RDI significantly increased the total phenolic content in skin (∼9.8%), PAs, and the AA. Consequently, after one season the application of DI positively affected the almond cv. Vairo phenols, however, several seasons must be evaluated in order to corroborate the present results.

Orchard recycling improves climate change adaptation and mitigation potential of almond production systems.

There is an urgent need to develop climate smart agroecosystems capable of mitigating climate change and adapting to its effects. In California, high commodity prices and increased frequency of drought have encouraged orchard turnover, providing an opportunity to recycle tree biomass in situ prior to replanting an orchard. Whole orchard recycling (WOR) has potential as a carbon (C) negative cultural practice to build soil C storage, soil health, and orchard productivity. We tested the potential of this practice for long term C sequestration and hypothesized that associated co-benefits to soil health will enhance sustainability and resiliency of almond orchards to water-deficit conditions. We measured soil health metrics and productivity of an almond orchard following grinding and incorporation of woody biomass vs. burning of old orchard biomass 9 years after implementation. We also conducted a deficit irrigation trial with control and deficit irrigation (-20%) treatments to quantify shifts in tree water status and resilience. Biomass recycling led to higher yields and substantial improvement in soil functioning, including nutrient content, aggregation, porosity, and water retention. This practice also sequestered significantly higher levels of C in the topsoil (+5 t ha-1) compared to burning. We measured a 20% increase in irrigation water use efficiency and improved soil and tree water status under stress, suggesting that in situ biomass recycling can be considered as a climate smart practice in California irrigated almond systems.

Linking diverse salinity responses of 14 almond rootstocks with physiological, biochemical, and genetic determinants.

Fourteen commercial almond rootstocks were tested under five types of irrigation waters to understand the genetic, physiological, and biochemical bases of salt-tolerance mechanisms. Treatments included control (T1) and four saline water treatments dominant in sodium-sulfate (T2), sodium-chloride (T3), sodium-chloride/sulfate (T4), and calcium/magnesium-chloride/sulfate (T5). T3 caused the highest reduction in survival rate and trunk diameter, followed by T4 and T2, indicating that Na and, to a lesser extent, Cl were the most toxic ions to almond rootstocks. Peach hybrid (Empyrean 1) and peach-almond hybrids (Cornerstone, Bright's Hybrid 5, and BB 106) were the most tolerant to salinity. Rootstock's performance under salinity correlated highly with its leaf Na and Cl concentrations, indicating that Na+ and Cl- exclusion is crucial for salinity tolerance in Prunus. Photosynthetic rate correlated with trunk diameter and proline leaf ratio (T3/T1) significantly correlated with the exclusion of Na+ and Cl-, which directly affected the survival rate. Expression analyses of 23 genes involved in salinity stress revealed that the expression differences among genotypes were closely associated with their performance under salinity. Our genetic, molecular, and biochemical analyses allowed us to characterize rootstocks based on component traits of the salt-tolerance mechanisms, which may facilitate the development of highly salt-tolerant rootstocks.

Enhancing Nut Quality Parameters and Sensory Profiles in Three Almond Cultivars by Different Irrigation Regimes.

The climate change is already affecting many agricultural systems and human environments, and the implementation of adaptation strategies, especially those related to irrigated agriculture in semiarid regions, is urgent. In this regard, deep knowledge about the effects that irrigation has on the food quality parameters will allow us to estimate the potential benefits of deficit irrigation (DI) strategies. This work presents the effects on the quality parameters of three almond cultivars (Marta, Guara, and Lauranne) subjected to three irrigation doses: (i) full-irrigated treatment (FI) at 100% crop evapotranspiration (ETC), (ii) an overirrigated treatment at 150% ETC (150% ETC), and (iii) regulated deficit irrigation (RDI65) treatment, in which irrigation was done as in FI, expect during the kernel-filling period when this treatment received 65% ETC. According to experimental findings, the cultivar most sensitive to water stress was Marta, having the most significant improvements for RDI65. In general, the effects of the irrigation dose on the morphological and physicochemical parameters were not huge but some improvements were observed in key parameters such as the color and contents of specific sugars, organic acids, and unsaturated fatty acids. Thus, it can be concluded that the irrigation dose did not drastically affect the fruit almond quality, although it is possible to improve several key parameters when a moderate RDI strategy is applied.

Comparison of phenological traits, growth patterns, and seasonal dynamics of non-structural carbohydrate in Mediterranean tree crop species.

Despite non-structural carbohydrate (NSC) importance for tree productivity and resilience, little is known about their seasonal regulations and trade-off with growth and reproduction. We characterize the seasonal dynamics of NSC in relation to the aboveground phenology and temporal growth patterns of three deciduous Mediterranean species: almond (Prunus dulcis (Mill.) D. A. Webb), walnut (Juglans regia L.) and pistachio (Pistacia vera L.). Seasonal dynamics of NSC were synchronous between wood tissues from trunk, branches and twigs. Almond had almost identical levels and patterns of NSC variation in twigs, branches and trunks whereas pistachio and walnut exhibited clear concentration differences among plant parts whereby twigs had the highest and most variable NSC concentration, followed by branches and then trunk. While phenology had a significant influence on NSC seasonal trends, there was no clear trade-off between NSC storage and growth suggesting that both were similarly strong sinks for NSC. A temporal trade-off observed at the seasonal scale was influenced by the phenology of the species. We propose that late senescing species experience C allocation trade-off at the end of the growing season because of C-limiting thermal conditions and priority allocation to storage in order to survive winter.

Phytoprostanes and Phytofurans-Oxidative Stress and Bioactive Compounds-in Almonds are Affected by Deficit Irrigation in Almond Trees.

Almonds have gained consumers' attention due to their health benefits (they are rich in bioactive compounds) and sensory properties. Nevertheless, information about phytoprostanes (PhytoPs) and phytofurans (PhytoFs) (new plant markers of oxidative stress and compounds with biological properties for human health) in almonds under deficit irrigation is scarce or does not exist. These compounds are plant oxylipins synthesized by the oxidation of α-linolenic acid (ALA). Besides, they are biomarkers of plant oxidative degradation and biologically active molecules involved in several plant defense mechanisms. hydroSOStainable or hydroSOS mean plant foods made from from plants under controlled water stress. Almonds are a good source of polyunsaturated fatty (PUFAs) acids, including a high content of ALA. This paper aimed to describe the influence of diverse irrigation treatments on in vitro anti-oxidant activity (AAc) and total phenolic content (TPC), as well as on the level of ALA, PhytoP, and PhytoF in "Vairo" almonds. The AAc and TPC were not affected by the irrigation strategy, while the in vivo oxidative stress makers, PhytoPs and PhytoFs, exhibited significant differences in response to water shortage. The total PhytoP and PhytoF contents ranged from 4551 to 8151 ng/100 g dry weight (dw) and from 33 to 56 ng/100 g dw, respectively. The PhytoP and PhytoF profiles identified in almonds showed significant differences among treatments. Individual PhytoPs and PhytoFs were present above the limit of detection only in almonds obtained from trees maintained under deficit irrigation (DI) conditions (regulated deficit irrigation, RDI, and sustained deficit irrigation, SDI) but not in control almonds obtained from fully irrigated trees. Therefore, these results confirm PhytoPs and PhytoFs as valuable biomarkers to detect whether an almond-based product is hydroSOStainable. As a final conclusion, it can be stated that almond quality and functionality can be improved and water irrigation consumption can be reduced if controlled DI strategies are applied in almond orchards.

Evaluating insecticide coverage and determining its effect on the duration of control for navel orangeworm (Amyelois transitella Walker) (Lepidoptera: Pyralidae) in California almonds.

BACKGROUND: Insecticide application is essential to control navel orangeworm (Amyelois transitella) in California almonds (Prunus dulcis), but coverage is challenging. Laboratory and field trials were conducted from 2014 to 2017 to quantify insecticide deposition and duration of control. RESULTS: In the laboratory for filter paper, photolysis reduced the contact toxicity of bifenthrin, and its half-life was 6.2 days. For chlorantraniliprole applied in the field, there was 87-94% less insecticide deposited in the almond suture, the most vulnerable part of the nut, than on the hull. For chlorantraniliprole, adjuvant choice (alcohol ethoxylate versus mineral oil) affected both initial insecticide deposition and half-life. Chlorantraniliprole degradation was greater at 6.1 m than at 3 m for both adjuvants assessed, whereas contact mortality was similar at both heights for the alcohol ethoxylate adjuvant. CONCLUSION: The combination of photolysis and differential distribution of insecticide on the nut can account for the variable control observed in the field. This was particularly problematic in the upper canopy and adjuvant choice affected deposition and insecticide degradation. Less than 1% of the insecticide in the tank was deposited on the almond suture. These results demonstrating the fraction of the insecticide in the sprayer tank deposited on the nut target, combined with reduced coverage in the upper canopy are also applicable to the control of A. transitella in pistachio (Pistacia vera) and walnut (Juglans regia) orchards. © 2019 Society of Chemical Industry.

Methyl jasmonate enhances salt tolerance of almond rootstocks by regulating endogenous phytohormones, antioxidant activity and gas-exchange.

The effects of methyl jasmonate (MeJA) foliar application (0, 0.025, 0.050 and 0.075 mM) on the growth and physiological responses of two almond rootstocks (GF677 and bitter almond) exposed to various concentrations of NaCl in irrigation water (0, 50, 100 and 150 mM) were evaluated. 60 days after salt stress exposure, the mitotic index of root apical meristem cells as well as shoot and root growth, activity of main antioxidant enzymes, gas exchange parameters and contents of cytokinins and ABA were determined. Salt stress decreased the plants' growth, particularly at higher levels. Application of MeJA in optimal concentrations of 0.025 to 0.05 mM alleviated the adverse effect of salt stress by increasing the photosynthetic rate, activity of antioxidant enzymes (APX, SOD and POX), root and shoot dry mass, as well as cell membrane integrity. Furthermore, MeJA application brought about a two-fold increase in the concentration of leaf cytokinins. This reposition of cytokinins was due to restriction of both the activity of cytokinin oxidase and gene expression of this enzyme. The MeJA mitigating effect on the growth of salt-stressed plants could be a result of the inhibition of cytokinin decline under salt stress. The results revealed the effective impact of endogenous cytokinins in protective and growth improvement effects of MeJA on almond rootstocks under salt stress.

Ecology and Economics of Using Native Managed Bees for Almond Pollination.

Native managed bees can improve crop pollination, but a general framework for evaluating the associated economic costs and benefits has not been developed. We conducted a cost-benefit analysis to assess how managing blue orchard bees (Osmia lignaria Say [Hymenoptera: Megachildae]) alongside honey bees (Apis mellifera Linnaeus [Hymenoptera: Apidae]) can affect profits for almond growers in California. Specifically, we studied how adjusting three strategies can influence profits: (1) number of released O. lignaria bees, (2) density of artificial nest boxes, and (3) number of nest cavities (tubes) per box. We developed an ecological model for the effects of pollinator activity on almond yields, validated the model with published data, and then estimated changes in profits for different management strategies. Our model shows that almond yields increase with O. lignaria foraging density, even where honey bees are already in use. Our cost-benefit analysis shows that profit ranged from -US$1,800 to US$2,800/acre given different combinations of the three strategies. Adding nest boxes had the greatest effect; we predict an increase in profit between low and high nest box density strategies (2.5 and 10 boxes/acre). In fact, the number of released bees and the availability of nest tubes had relatively small effects in the high nest box density strategies. This suggests that growers could improve profits by simply adding more nest boxes with moderate number of tubes in each. Our approach can support grower decisions regarding integrated crop pollination and highlight the importance of a comprehensive ecological economic framework for assessing these decisions.

Aspergillus section Flavi and aflatoxins in dried figs and nuts in Algeria.

The presence of Aspergillus section Flavi and aflatoxin (AF) contamination was investigated in 112 samples of peanuts, almonds and dried figs collected in Algeria. The occurrence of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) in different commodities has been determined with a sensitive method based on high performance liquid chromatography (HPLC) coupled with fluorescence detection with post-column photochemical derivatisation. Analytical results indicated that 28 samples of peanuts, 16 samples of almonds and 26 samples of dried figs contained detectable levels of AFs. A total of 69 samples (61.6%) were contaminated with AFB1 ranging from the limit of quantification to 174 µg kg-1. AFB2 was found in 12 samples (10.7%) and varied from 0.18 to 193 µg kg-1. Seven samples revealed AF concentrations lower than the limit of quantification. Eleven peanut and fourteen dried fig samples exceeded the European maximum limits for AFB1.