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1.
A laboratory incubation study with clover grass pasture soils of seven different ages (0, 1, 2, 3, 4, 5, and 16 production years) was carried out to determine initial soil carbon (C) and nitrogen (N) stocks and potentials for greenhouse gas emissions (N2O and CO2). Compared with the soil from the recently established pasture, an increase of total soil C and N was observed along with pasture age. Greenhouse gas emissions were low and not significantly different among the soils from younger pastures (0–5 years), but especially N2O emissions increased markedly in the soil from 16-year-old grass–clover. Low emissions might mainly be due to an early C limitation occurring in the soils from younger pastures, which was also corroborated by decreasing levels of cold water-extractable C and early shifts within the microbial community. However, higher emissions from the old pasture soil were offset by its increase in total soil C. A longer ley phase without soil disturbance may therefore be beneficial in terms of overall C sequestration in systems with temporary grass–clover swards.  相似文献   

2.
Grassland ecosystems in south-eastern Australia are important for dairy and livestock farming. Their productivity relies heavily on water availability, as well as the ecosystem services provided by soil microbial communities including carbon and nutrient cycling. Management practices such as compost application are being encouraged as a means to improve both soil water holding capacity and fertility, thereby buffering against the impacts of increasing climate variability. Such buffering consists of two complementary processes: resistance, which measures the ability of an ecosystem to maintain community structure and function during a period of stress (such as drying); and resilience, which measures the ability of an ecosystem to recover community structure and function post-stress. We investigated the effects of compost on the resistance and resilience of the grassland soil ecosystem under drying and drying with rewetting events, in a terrestrial model ecosystem. Overall, compost addition led to an increase in soil moisture, greater plant available P and higher plant δ15N. Soil C:nutrient ratios, mineral N content (NH4+ and NO3) and soil microbial PLFA composition were similar between amended and unamended soils. Rainfall treatment led to differences in soil moisture, plant above-ground and below-ground biomass, plant δ15N, soil mineral N content (NH4+ and NO3) and microbial biomass C, N and P composition but had no effects on soil C:nutrient ratios, plant available P and soil microbial PLFA composition. There was little interaction between rainfall and compost. Generally, the soil microbial community was resistant and resilient to fluctuations in rainfall regardless of compost amendment. However, these properties of the soil microbial community were translated to resilience and not resistance in soil functions. Overall, the results below-ground showed much greater response to rainfall than compost amendment. Water was the key factor shaping the soil microbial community, and nutrients were not strong co-limiting factors. Future projections of increasing rainfall variability will have important below-ground functional consequences in the grassland, including altered nutrient cycling.  相似文献   

3.
The main objective of this study was to investigate and compare the effects of fertilizer types on the counts of soil microorganisms, the mineral leaf composition, and productivity of three strawberry cultivars in the period 2012–2013. Two types of fertilizers were applied—mineral and microbiological. Significantly higher number of Azotobacter, ammonifiers, oligonitrophils, and total microbial count were observed under biofertilizers treatment. Significantly higher counts of fungi and actinomycetes were obtained under mineral fertilizer treatment, compared to other fertilizer treatments. The use of mineral fertilizer led to the most favorable balance of macronutrients and micronutrients in the leaf. In 2012, the generative potential and yield increased after mineral fertilization, whereas in 2013 these parameters were positively affected by mineral fertilizer and Biofertilizer 1. Given the obtained results, in order to improve technology of strawberry production, a partial substitution of mineral fertilizers by microbiological ones can be recommended.  相似文献   

4.
Abstract

An experiment was conducted to substitute mineral fertilizers with biofertilizers in strawberry to work out the yield, quality of strawberry and soil fertility. A 25% substitution of mineral fertilizer with biofertilizer increased the number of fruits/plant along with improving Juice content (89.55%), Total soluble solids (10.35°B), total sugar (6.69%), ascorbic acid (43.80?mg 100?g?1), anthocyanin content (81.05?mg 100?g?1), total phenol (5.97?mg Gallic acid equiv. g?1), flavonoids (0.12?mg g?1) and antioxidant capacity (2.13?µmol. Trolox equiv. 100?g?1). The available N and K content in post-harvest soils were improved significantly with 75% RDF + Azospirillium @ 2?g plant?1 + PSB @ 2?g plant?1 + topdressing of 25% K treatments (200.10 and 211.70?kg ha?1, respectively). Viable count of soil microorganisms (Bacteria, actinomycetes and fungi) was also estimated maximum (4066, 190 and 11.33?×?104 cfu g?1?dry soil, respectively) with substitution of 25% of mineral fertilizer either with Azotobacter or Azospirillum.  相似文献   

5.
Plant roots are exposed to a variety of nitrogen forms (e.g., nitrate, ammonium, amino acids) and take up these forms at different rates. Many studies have investigated whether plants prefer nitrate, ammonium, or amino acids; but studies may not be comparable because they used substrate concentrations between 100 and 2000 μmol L–1. This study tests the hypothesis that substrate concentrations from 10 to 1750 μmol L–1 affect plant preference for N forms. Nitrogen uptake by the herb Ocimum basilicum and the evergreen tree Eucalyptus regnans was examined by placing roots of intact seedlings in equimolar mixtures of nitrate, ammonium, and glycine in which one of the N forms was 15N‐labelled (and 13C‐labelled in the case of glycine). In both species, preference for N forms was affected by substrate concentration. At 10 μmol L–1 (O. basilicum) or 10 and 50 μmol L–1 (E. regnans), rates of N uptake did not differ among N forms. At substrate concentrations of 50 μmol L–1 and greater O. basilicum took up ammonium the fastest, glycine the slowest, and nitrate at an intermediate rate. At substrate concentrations from 100 to 1750 μmol L–1, E. regnans took up ammonium the fastest with glycine and nitrate taken up at slower rates. The absence of significant differences at lower concentrations was a true biological effect rather than a function of larger relative errors. This study demonstrates that substrate concentration has a large effect on plant preference for N forms, and sounds a warning for studies of N nutrition that do not consider the concentration‐dependence of plant preference for N forms.  相似文献   

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There is no information on the effect of sulfuryl fluoride (SF) on durum wheat technological properties and products made from fumigated durum wheat. Durum wheat and semolina were exposed to a range of SF applications under conditions that might be typically encountered in bulk storage facilities used in many countries. SF greatly reduced the germination percentage of fumigated durum wheat, with increasing impact under higher SF concentration, grain moisture content, and fumigation temperature. SF greatly reduced seed germination percentage, impacting more the higher the SF concentration. SF had little to no effect on grain test weight, 1,000‐grain weight, hardness, protein content, semolina ash content, and mixograph properties. At the highest SF concentration (31.25 mg/L for 48 h) there was a tendency for pasta cooking loss to be increased but still acceptable, and other pasta properties were largely unaffected. Fumigation with SF did not have any impact on the baking properties of a wholemeal durum flour–commercial flour mix. Therefore, SF is not recommended if the grains are to be used as seeds for agricultural production, but for the production of semolina, pasta, and bread, SF used under typical fumigation conditions has little to no impact on technological properties of durum wheat.  相似文献   

9.
Triticeae γ-type seed prolamins have undergone many rounds of gene duplications during evolution. However, the population genetics of total Triticeae γ-prolamin genes has not been studied in an evolutionary perspective so far. Here, evolutionary pattern of γ-prolamin multigene family containing 557 sequences from wheat and closely related species (γ-gliadins), rye (γ-secalin) and barley (γ-hordeins) was investigated. Furthermore, Triticeae genomes were searched for low immuno-reactive celiac disease (CD) epitope contents in their γ-prolamins for the possibility of developing less immunogenic cultivars. Large numbers of haplotypes with segregating sites and mutations in γ-type seed prolamin multigene family were evident. Polymorphism analyses of both promoters and coding regions of species-specific γ-prolamins demonstrated no deviation from neutral theory. The sliding window revealed that most of the singleton polymorphic sites are resided in the variable R1 domain. Furthermore, the significant negative Tajima’s D and H tests’ values of each groups 1, 2, 3, and 8 showed a selective sweep for R and D genome duplication processes. The dN/dS ratio analysis revealed strong purifying selection acting upon duplication of the two ancestral branches, while the neutral selection among overall groups was observed. Our results support previously reported findings that the groups of 2, 3, 8 (D genome) and 10 (A genome) can potentially be recommended for selection approaches or genetic engineering of less immunogenic cereal grains. Furthermore, the results provide new insights on the evolutionary dynamics of γ-prolamin multigene family, polyploidy speciation and phylogeny of Triticeae species.  相似文献   

10.
Concern has been expressed over the status of the bottlenose dolphin population that uses the Moray Firth and adjacent waters in NE Scotland. Consequently, part of this population's range has been proposed as a Special Area of Conservation. Efforts to manage and monitor the status of this population require information on the level of genetic diversity within the population and its genetic relatedness to neighbouring populations to appropriately designate units for management and monitoring. Here we examine mitochondrial genetic diversity within the NE Scotland population, and compare this to other regions around the UK and Ireland. Sequence analysis of 549bp of the mitochondrial DNA control region identified eight unique haplotypes in a sample of 29 individuals. Analysis of molecular variance suggests that the Moray Firth population is genetically more closely related to Welsh animals than to its nearest neighbour population in west Scotland. Furthermore, measures of within-population genetic diversity were markedly lower in the Moray Firth than any other sampled region. The low levels of mtDNA genetic variability observed and its apparent geographic isolation provide further support for the precautionary approach currently being applied to the management of this population, despite the lack of direct evidence of harm.  相似文献   

11.
It is generally believed that the French paradox is related to the consumption of red wine and not other varieties of wine, including white wine or champagne. Some recent studies have indicated that white wine could also be as cardioprotective as red wine. The present investigation compares the cardioprotective abilities of red wine, white wine, and their principal cardioprotective constituents. Different groups of rats were gavaged with red wine, white wine, resveratrol, tyrosol, and hydroxytyrosol. Red wine and its constituent resveratrol and white wine and its constituents tyrosol and hydroxytyrosol all showed different degrees of cardioprotection as evidenced by their abilities to improve postischemic ventricular performance, reduce myocardial infarct size and cardiomyocyte apoptosis, and reduce peroxide formation. It was discovered in this study that although each of the wines and their components increased the enzymatic activities of the mitochondrial complex (I-IV) and citrate synthase, which play very important roles in oxidative phosphorylation and ATP synthesis, some of the groups were more complex-specific in inducing the activity compared to the other groups. Cardioprotective ability was further confirmed by increased expression of phospho-Akt, Bcl-2, eNOS, iNOS, COX-1, COX-2, Trx-1, Trx-2, and HO-1. The results of this study suggest that white wine can provide cardioprotection similar to red wine if it is rich in tyrosol and hydroxytyrosol.  相似文献   

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Investigating population genetic structure and diversity, and resistance to pathogens in crop wild relatives are key steps to assess appropriate conservation and breeding programs. The Caucasian wild apple (Malus orientalis Uglitzk.) is an emblematic fruit tree of the Hyrcanian forest and is supposed to be a contributor to the cultivated apple genome (Malus domestica Borkh. Yet, no study has investigated its population structure, diversity and susceptibility to the two main pathogens of apples, the apple scab (Venturia inaqualis) and the powdery mildew (Podosphaera leucotricha). Here, we investigated population genetic structure and diversity of M. orientalis in the Hyrcanian forest as a mean to identifying future targeted populations for apple conservation and breeding programs. We genotyped using multilocus microsatellite 100 M. orientalis trees sampled in 14 sites. These trees were also screened for presence/absence of six (Rvi6, Vr, Rvi4, Rvi15, Rvi5 and Rvi11) and three (Pl-1, Pl-w, Pl-d) resistance genes to the apple scab and the powdery mildew respectively. Our results showed significant but weak between-site genetic differentiation and isolation by distance pattern suggesting substantial historical gene flow for M. orientalis in this area. We also detected a West-Eastern genetic structure across the Hyrcanian forest with five main populations showing admixture. We also showed a high diversity of resistance genes to apple scab across sites; in contrast, we only found one resistance gene to powdery mildew. These results are a first glimpse to settle wild apple conservation programs in Iran and pinpoint Iranian wild apple populations as an untapped source for apple breeding.  相似文献   

14.
OBJECTIVES: To study dietary diversity and its relationship with socio-economic and nutritional characteristics of women in an urban Sahelian context. DESIGN: A qualitative dietary recall was performed over a 24-h period. Dietary diversity scores (DDS = number of food groups consumed) were calculated from a list of nine food groups (DDS-9) or from a list of 22 food groups (DDS-22) which detailed both micronutrient- and energy-dense foods more extensively. Body mass index (BMI), mid upper-arm circumference and body fat percentage were used to assess the nutritional status of the women. SETTING AND SUBJECTS: Five hundred and fifty-seven women randomly selected in two districts of Ouagadougou, the capital of Burkina Faso. RESULTS: The mean DDS-9 and DDS-22 were 4.9 +/- 1.0 and 6.5 +/- 1.8 food groups, respectively. In the high tertile of DDS-22, more women consumed fatty and sweetened foods, fresh fish, non-fatty meat and vitamin-A-rich fruits and vegetables. The DDS-9 was not associated with the women's socio-economic characteristics whereas the DDS-22 was higher when the women were younger, richer and had received at least a minimum education. Mean BMI of the women was 24.2 +/- 4.9 kg m-2 and 37% of them were overweight or obese (BMI > or = 25 kg m-2). Neither the DDS-9 nor the DDS-22 was associated with the women's anthropometric status, even though there was a trend towards fewer overweight women in the lowest tertile of DDS-22. CONCLUSION: In this urban area, the qualitative measurement of dietary diversity is not sufficient to identify women at risk of under- or overweight.  相似文献   

15.
Two maize cultivars, Shaandan 9 (S9) and Shaandan 911 (S911), were investigated to explore the ameliorating effects of nitrogen (N) addition on their growth, water status, and N metabolism under long-term drought stress (DS). Elevated N rate increased dry matter, grain yield, relative water content, nitrate reductase activity, soluble protein concentration, and concentrations of free proline and endogenous glycinebetaine (main contributors to osmoregulation) of both cultivars under DS than control. The responses under DS were more significant for S911 than those for S9, especially at high N rate. Additionally, S9 maintained greater evaluated parameters than S911 with no N addition under DS, and these differences decreased with N application. Correlations were more evident among all parameters under DS than those under control. Thus, moderate N plays an evident physiological role in alleviation of DS effects on plant growth by improving water status and N metabolism, especially for drought-sensitive cultivars.  相似文献   

16.
Since 1992, efforts to recover the US federally endangered Great Lakes piping plover (Charadrius melodus) have included population supplementation with captive-reared young raised from abandoned eggs. Using banding data collected 1993-2008 and Cormack-Jolly-Seber models in program MARK we estimated resighting rates (ρ) and apparent survival (Φ) of first-year (1) and after-first-year (2+) plovers. Reproductive success was measured by estimating mean number of eggs laid, chicks hatched and chicks fledged per wild-reared or captive-reared parent, and these values were compared with a permutation test. The best-supported mark-resighting model indicated wild-reared plovers had higher Φ1 and Φ2+ than captive-reared plovers. Breeding propensity influenced detection of wild plovers, whereas unique band combinations facilitated detection of yearling captive-reared plovers. Captive-reared (n = 10) and wild-reared (n = 57) plovers laid similar numbers of eggs, but wild-reared plovers hatched 36% more chicks and fledged 56% more young. Reproductive values derived from matrix models suggest captive-reared piping plovers are less fit than similarly aged wild-reared birds upon release and demonstrate reduced fitness in subsequent years. The Great Lakes captive-rearing effort has successfully produced a minimum of 10 breeding adults from 192 eggs that otherwise would have had no reproductive value; these captive-reared individuals now constitute up to 3% of the total population. Small scale salvage and captive-rearing of abandoned eggs should be considered as a technique to supplement existing recovery efforts in highly imperiled populations.  相似文献   

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Analysis of differential pore-volume distribution (PVD) patterns of commercial clinoptilolite fractions [(<125 µ (Z8; fine), 125–250 µ (Z9; medium), and >250 µ (Z10; coarse)] has been conducted experimentally using an analyzer to measure the nitrogen (N2) adsorption isotherms. The differential PVDs of the clinoptilolite fractions were calculated from the hysteresis loop according to the adsorption and desorption curves of the Barret, Joyner, and Halenda (BJH) model. The adsorption and desorption cycles of BJH produced heterogeneous as well as dissimilar differential PVD patterns with assorted peaks. While the adsorption curve has prolonged up to 300 nm, the desorption cycle was confined up to 190-nm pore diameter only. In the adsorption cycle, all the clinoptilolite fractions displayed U-shaped curves and had a differential pore volume in the range of 3 × 10–3 to 8 × 10–3 cm3/g A° in the micropore region with a sole peak at 1.75 nm for the fine fraction (Z8). In contrast, the curves were linear in the mesoporous region for all the fractions, with the fine fraction (Z8) having the greatest differential pore volume, whereas the other two fractions were almost parallel to each other. The desorption cycle has revealed an inverted V-shape curve with no definite patterns for the microporous region. Although the adsorption cycle could ascertain the micropore region, the desorption cycle was unable to do so. It was apparent from the differential PVD of the BJH model that fraction size has a major role in determining the textural properties of clinoptilolite fractions.  相似文献   

20.
The first results of the Women's Health Initiative dietary intervention trial were published in the USA in February. This is a colossal intervention designed to see if diets lower in fat and higher in fruits, vegetables and grains than is usual in high-income countries reduce the incidence of breast cancer, colorectal cancer, heart disease and other chronic diseases, in women aged 50-79 years. As interpreted by US government media releases, the results were unimpressive. As interpreted by a global media blitz, the results indicate that food and nutrition has little or nothing to do with health and disease. But the trial was in key respects not reaching its aims, was methodologically controversial, and in any case has not produced the reported null results. What should the public health nutrition profession do about such messes?  相似文献   

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