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排序方式: 共有274条查询结果,搜索用时 15 毫秒
41.
Apple (Malus × domestica Borkh.) fruit intended for long-term storage are frequently harvested commercially before becoming fully ripe, often resulting in poor aroma development. Since postharvest calcium dips have proved effective for the enhancement of flavor-related volatile esters after cold storage of apples, this study was undertaken in order to assess whether preharvest calcium sprays (7 weekly applications at 1.6%, w/v, 81-123 days after full bloom) could also aid in improving this important attribute at harvest. This procedure significantly increased calcium content in treated fruit. The emission of aroma-related volatile esters by untreated and calcium-treated 'Fuji' apples was then monitored during maturation and ripening over two months prior to commercial harvest. Results indicate that most of the compounds contributing to overall flavor in ripe fruit were enhanced in response to preharvest calcium applications, suggesting that this procedure may be suitable for the improvement of fruit aroma at harvest. The emission of acetate esters was particularly favored, consistent with higher acetaldehyde contents in treated fruit. These effects arose apparently from increased pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) activities, possibly leading to a better supply of alcohols and acyl CoAs for ester biosynthesis. 相似文献
42.
43.
Roberto Quiroz Joan O. Grimalt Pilar Fernandez Lluis Camarero Jordi Catalan Evzen Stuchlik Hansjoerg Thies Ulrike Nickus 《Water, air, and soil pollution》2011,215(1-4):655-666
Polycyclic aromatic hydrocarbons (PAHs) were analyzed in 70 soils distributed in mountain areas such as Montseny (300?C1,700 m), Pyrenees (1,500?C2,900 m), Alps (1,100?C2,500 m), and Tatras (1,400?C1,960 m). Average total PAH concentrations, excluding retene and perylene, were about 400 ng/g in the Pyrenees and 1,300?C1,600 ng/g in the other mountain ranges. No correlations between PAH concentrations and total organic carbon were observed. Retene was the major PAH in the Pyrenean soils of lower altitude. No altitudinal dependence was found between soil PAH concentrations and elevation for the whole dataset. However, in the Tatra soils a statistically significant correlation with altitude was observed involving higher concentrations at higher altitude. This correlation was due to the statistically significant altitudinal dependence of the more volatile PAHs. Another observed altitudinal trend concerned the benz[a]anthracene/(benz[a]anthracene + chrysene + triphenylene) and the benzo[a]pyrene/(benzo[a]pyrene + benzo[e]pyrene) ratios that exhibited a decrease in the more chemically labile compounds, benz[a]anthracene and benzo[a]pyrene, respectively, in the soils located at higher altitude. This observation is consistent with the expected higher photooxidation at higher mountain altitude. 相似文献
44.
Orozco-Solano MI Priego-Capote F Luque de Castro MD 《Journal of agricultural and food chemistry》2011,59(18):9806-9814
The stability of the antioxidant fraction in edible vegetable oils has been evaluated during a simulated deep frying process at 180 °C. Four edible oils (i.e., extra-virgin olive oil with a 400 μg/mL overall content in naturally existing phenols; high-oleic sunflower oil without natural content of these compounds but enriched either with hydrophilic antioxidants isolated from olive pomace or with an oxidation inhibitor, dimethylsiloxane; and sunflower oil without enrichment) were subjected to deep heating consisting of 20 cycles at 180 °C for 5 min each. An oil aliquot was sampled after each heating cycle to study the influence of heating on the antioxidant fraction composed of hydrophilic and lipophilic antioxidants such as phenols and tocopherols, respectively. The decomposition curves for each group of compounds caused by the influence of deep heating were studied to compare their resistance to oxidation. Thus, the suitability of olive pomace as raw material to obtain these compounds offers an excellent alternative to the use of olive-tree materials different from leaves. The enrichment of refined edible oils with natural antioxidants from olive pomace is a sustainable strategy to take benefits from this residue. 相似文献
45.
A.G. Cirilo J. Dardanelli M. Balzarini F.H. Andrade M. Cantarero S. Luque H.M. Pedrol 《Field Crops Research》2009
The use of genotypes with improved performance for nitrogen (N) capture and use would be of great benefit through reducing production costs and pollution risks in maize cropping. The identification of morpho-physiological traits responsible for a better behavior in a target N environment is useful for cultivar selection, and become crucial for maize breeding improvement. This study analyzed, in a set of Argentinean commercial hybrids of maize, the grain yield (GY) variability in response to soil N availability at several locations representative of the main maize production region of Argentina during 2003–2004 growing season. The objectives of this work were to: (i) detect environmental groups for GY responses, (ii) identify morpho-physiological traits that were associated to winner genotypes in each detected environmental group, and (iii) assess genetic correlations between those traits. To generate more variation in soil N availability two N-fertilizer rates were applied in each experimental site (0 and 250 kg N ha−1, except for Balcarce where only 250 kg N ha−1 was tested). Morpho-physiological traits included in the analysis were related to N and radiation capture, use and partitioning, plant architecture, and leaf senescence. Grain yield components were also included. As expected, environment (E) effect explained the higher portion of GY variation (i.e., 82%), but genotype (G) and G × E interaction (GE) also significantly contributed (i.e., 9% each). Three environmental groups for GY were identified according to N availability. Morpho-physiological traits related to resource capture, use, and partitioning during the post-silking period are proposed as desirables for broad adaptation. In turn, a high N partitioning to grains after silking was associated with good hybrid behavior under high N availability and warm climate. On the other hand, a better grain yield performance when N became more limited appeared strongly related to an efficient canopy to sustain resource capture up to maturity. More studies are required in a wide range of environments to confirm identified traits and underlying physiological mechanisms. Nevertheless, our findings highlight the existence of differences in ideal plant-type for environments differing in N availability to be considered in maize breeding programs. 相似文献
46.
We studied the relief of water stress associated with fruit thinning in pear (Pyrus communis L.) trees during drought to determine what mechanisms, other than stomatal adjustment, were involved. Combinations of control irrigation (equal to crop water use less effective rainfall) and deficit irrigation (equal to 20% of control irrigation), fruit load (unthinned and thinned to 40 fruits per tree) and root pruning (pruned and unpruned) treatments were applied to pear (cv. 'Conference') trees during Stage II of fruit development. Daily patterns of midday stem water potential (Psi(stem)) and leaf conductance to water vapor (g(l)) of deficit-irrigated trees differed after fruit thinning. In response to fruit thinning, gl progressively declined with water stress until 30 days after fruit thinning and then leveled off, whereas the effects of decreased fruit load on Psi(stem) peaked 30-40 days after fruit thinning and then tended to decline. Soil water depletion was significantly correlated with fruit load during drought. Our results indicate that stomatal adjustment and the resulting soil water conservation were the factors determining the Psi(stem) response to fruit thinning. However, these factors could not explain differences in daily patterns between g(l) and Psi(stem) after fruit thinning. In all cases, effects of root pruning treatments on Psi(stem) in deficit-irrigated trees were transitory (Psi(stem) recovered from root pruning in less than 30 days), but the recovery of Psi(stem) after root pruning was faster in trees with low fruit loads. This behavior is compatible with the concept that the water balance (reflected by Psi(stem) values) was better in trees with low fruit loads compared with unthinned trees, perhaps because more carbon was available for root growth. Thus, a root growth component is hypothesized as a mechanism to explain the bimodal Psi(stem) response to fruit thinning during drought. 相似文献
47.
Llop P Donat V Rodríguez M Cabrefiga J Ruz L Palomo JL Montesinos E López MM 《Phytopathology》2006,96(8):900-907
ABSTRACT An atypical strain of Erwinia amylovora was isolated near an outbreak of fire blight at a nursery in Spain in 1996. It was obtained from a Crataegus plant showing typical symptoms and was identified as E. amy-lovora by biochemical tests and enrichment-enzyme-linked immuno-sorbent assay, but not by polymerase chain reaction using primers based on the pEA29 sequence. Nevertheless, with primers from chromosomal regions, the isolate gave the expected amplification band. This strain carries one plasmid of approximately 70 kb, with no homology with the 29-kb plasmid common to all pathogenic strains, or with a large plasmid present in some E. amylovora strains. Growth of the strain in minimal medium without thiamine was slower compared with cultures in the same medium with thiamine, a characteristic typical of strains cured of the 29-kb plasmid. Nevertheless, aggressiveness assays on pear, apple, and Pyracantha plants and in immature pear fruit showed that this strain exhibited a virulence level similar to other strains containing pEA29. To the best of our knowledge, this is the first report of the isolation from naturally infected plant material of a pathogenic strain of E. amylovora without pEA29, but with a plasmid of approximately 70 kb not previously described. 相似文献
48.
Response of winter root starch concentration to severe water stress and fruit load and its subsequent effects on early peach fruit development 总被引:1,自引:0,他引:1
Effect of water stress during stage III of peach fruit development on winter root starch concentration (RSC) and subsequent reproductive development was studied. Two irrigation treatments were applied in two consecutive seasons (2003-2004): full irrigation (FI) and no irrigation during stage III of fruit development until visible leaf wilting (LWI), which occurred when midday stem water potential reached -1.80 MPa. Three fruit thinning intensities were applied within each irrigation treatment. The year 2005 was a recovery year in which all trees received full irrigation and commercial fruit thinning. Water deficit and high fruit loads in the previous season significantly reduced the concentration of winter RSC. Fruit set and fruit growth from full bloom to 30 days after full bloom (30 DAFB) increased with increasing winter RSC before other factors, such as inter-fruit competition and availability of carbon from current photosynthesis, came into play. Consequently, severe water stress reduced the total number of fruits and fruit dry mass growth 30 DAFB. However, during the recovery year and after fruit thinning, fruit loads were similar between irrigation treatments and yield capacity remained unaffected. Peach fruit production recovered quickly from the deleterious effects of two consecutive years of water stress because of a combination of two factors: (1) reduced initial fruit set that was still adequate to achieve a commercial crop; and (2) the low sensitivity of fruit growth 30 DAFB to winter RSC. 相似文献
49.
Cárdenas Liliana Cañas-Álvarez Jhon J. Vázquez Ana Boixadera Ester Casal Jordi 《Tropical animal health and production》2019,51(2):383-388
Tropical Animal Health and Production - Bovine brucellosis is a zoonotic disease that causes great economic losses. The disease is endemic in Colombia and animal movements from infected herds carry... 相似文献
50.
Emilio A. Martinez Cristina A. Martinez Josep M. Cambra Carolina Maside Xiomara Lucas Jose L. Vazquez Juan Maria Vazquez Jordi Roca Heriberto Rodriguez‐Martinez Maria Antonia Gil Inmaculada Parrilla Cristina Cuello 《Reproduction in domestic animals》2019,54(Z4):4-13
Commercial embryo transfer (ET) has unprecedented productive and economic implications for the pig sector. However, pig ET has been considered utopian for decades mainly because of the requirements of surgical techniques for embryo collection and embryo deposition into recipients, alongside challenges to preserve embryos. This situation has drastically changed in the last decade since the current technology allows non‐surgical ET and short‐ and long‐term embryo preservation. Here, we provide a brief review of the improvements in porcine ET achieved by our laboratory in the past 20 years. This review includes several aspects of non‐surgical ET technology and different issues affecting ET programmes and embryo preservation systems. The future perspectives of ET technology are also considered. We will refer only to embryos produced in vivo since they are the only type of embryos with possible short‐term use in pig production. 相似文献