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排序方式: 共有160条查询结果,搜索用时 46 毫秒
41.
Bassene JB Berti L Carcouet E Dhuique-Mayer C Fanciullino AL Bouffin J Ollitrault P Froelicher Y 《Journal of agricultural and food chemistry》2008,56(18):8635-8640
Sugar, organic acid, and carotenoid are the most important indicators of fruit taste and nutritional and organoleptic quality. These components were studied on fruit pulp of the cybrid between Willow leaf mandarin ( Citrus deliciosa Ten.) and Eureka lemon [ Citrus limon (L.) Burm.] and the two parents. The cybrid possessed nuclear and chloroplast genomes of Eureka lemon plus mitochondria from Willow leaf mandarin. The impact of new mitochondria on fruit quality was studied during the mature period. Levels of organic acids were slightly higher in the cybrid fruit pulp than in Eureka lemon. No significant difference in sugar and carotenoid content was observed between the cybrid and the lemon. Results confirm that the main genetic information for the biosynthesis of sugars, organic acids, and carotenoids is contained in the nucleus. In Citrus, cybridization can be used as a strategy to breed specific traits associated with mitochondrial genomes, such as male sterility, without affecting the main organoleptic and nutritional qualities. 相似文献
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Jean-Paul Laclau Jacques Ranger José Leonardo de Moraes Gonçalves Valérie Maquère Alex V. Krusche Armel Thongo M’Bou Yann Nouvellon Laurent Saint-André Jean-Pierre Bouillet Marisa de Cassia Piccolo Philippe Deleporte 《Forest Ecology and Management》2010,259(9):1771-1785
The sustainability of fast-growing tropical Eucalyptus plantations is of concern in a context of rising fertilizer costs, since large amounts of nutrients are removed with biomass every 6–7 years from highly weathered soils. A better understanding of the dynamics of tree requirements is required to match fertilization regimes to the availability of each nutrient in the soil. The nutrition of Eucalyptus plantations has been intensively investigated and many studies have focused on specific fluxes in the biogeochemical cycles of nutrients. However, studies dealing with complete cycles are scarce for the Tropics. The objective of this paper was to compare these cycles for Eucalyptus plantations in Congo and Brazil, with contrasting climates, soil properties, and management practices.The main features were similar in the two situations. Most nutrient fluxes were driven by crown establishment the two first years after planting and total biomass production thereafter. These forests were characterized by huge nutrient requirements: 155, 10, 52, 55 and 23 kg ha?1 of N, P, K, Ca and Mg the first year after planting at the Brazilian study site, respectively. High growth rates the first months after planting were essential to take advantage of the large amounts of nutrients released into the soil solutions by organic matter mineralization after harvesting. This study highlighted the predominant role of biological and biochemical cycles over the geochemical cycle of nutrients in tropical Eucalyptus plantations and indicated the prime importance of carefully managing organic matter in these soils. Limited nutrient losses through deep drainage after clear-cutting in the sandy soils of the two study sites showed the remarkable efficiency of Eucalyptus trees in keeping limited nutrient pools within the ecosystem, even after major disturbances. Nutrient input–output budgets suggested that Eucalyptus plantations take advantage of soil fertility inherited from previous land uses and that long-term sustainability will require an increase in the inputs of certain nutrients. 相似文献
45.
Dove ES Joly Y Knoppers BM 《Science (New York, N.Y.)》2011,333(6049):1575; author reply 1575-1575; author reply 1576
46.
Productivity is a poor predictor of plant species richness 总被引:5,自引:0,他引:5
Adler PB Seabloom EW Borer ET Hillebrand H Hautier Y Hector A Harpole WS O'Halloran LR Grace JB Anderson TM Bakker JD Biederman LA Brown CS Buckley YM Calabrese LB Chu CJ Cleland EE Collins SL Cottingham KL Crawley MJ Damschen EI Davies KF DeCrappeo NM Fay PA Firn J Frater P Gasarch EI Gruner DS Hagenah N Hille Ris Lambers J Humphries H Jin VL Kay AD Kirkman KP Klein JA Knops JM La Pierre KJ Lambrinos JG Li W MacDougall AS McCulley RL Melbourne BA Mitchell CE Moore JL Morgan JW Mortensen B 《Science (New York, N.Y.)》2011,333(6050):1750-1753
For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters(-2)) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity and richness. 相似文献
47.
Gancel AL Ollitrault P Froelicher Y Tomi F Jacquemond C Luro F Brillouet JM 《Journal of agricultural and food chemistry》2005,53(6):2224-2230
Volatile compounds were extracted by a pentane/ether (1:1) mixture from the leaves of six citrus somatic allotetraploid hybrids resulting from various combinations of lime, lemon, citron, sweet orange, and grapefruit. Extracts were examined by gas chromatography-mass spectrometry (GC-MS) and compared with those of their respective parents. All hybrids having an acid citrus parent exhibit the same relative contents in hydrocarbons and oxygenated compounds as the acid citrus, while the (grapefruit + orange) hybrid behaves similarly to its two parents. When volatile compound contents (microg g(-1)) are examined in detail, several behaviors are encountered in hybrids and seem to depend on the presence/absence of the considered parental compound and on the corresponding hybrid combination. Meanwhile, the sesquiterpene hydrocarbons are present in all hybrids at concentrations systematically lower than those of the highest parental producers. Statistical analyses show that hybrids exhibit hardly discriminable aromatic profiles, meaning that no strong dominance of one or the other parent was observed in hybrids with regards to the leaf volatile compound production. 相似文献
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No��mie Gaudio Philippe Balandier Gwena?l Philippe Yann Dumas Fr��d��ric Jean Christian Ginisty 《European Journal of Forest Research》2011,130(1):77-89
Depending on its developmental and morphological characteristics, shrubby or herbaceous understorey vegetation interacts differently with tree seedlings during the regeneration process. In acidic temperate forests, three common understorey plant species??Calluna vulgaris (L.) Hull, Pteridium aquilinum (L.) Kuhn in Kersten, Molinia caerulea (L.) Moench??are known to rapidly colonize forest gaps. Therefore, they often develop at the expense of light-demanding Scots pine (Pinus sylvestris L.) seedlings. An experiment was set up in a nursery in central France to mimic early competition occurring in a newly created gap between Scots pine seedlings and these three common understorey species (young forest-harvested individuals planted at 5 densities from 0 to 57 plants m?2). Pine seedling survival and growth (height, diameter, shoot and root biomass) and a functional trait (leaf mass on an area basis, LMA) were measured for 2 years, and cross-analysed against plant density, plant cover and available light. When understorey plant density increased, pine seedling diameter growth and biomass were negatively affected by all three plant species; height growth only slowed beneath Pteridium. These negative effects were closely linked to competition for light beneath Pteridium and Molinia. The application of the Beer?CLambert law gave an extinction coefficient k that was high for Pteridium, intermediate for Molinia and much lower for Calluna. LMA was confirmed as an effective foliar trait to reflect the degree of stress undergone by pine seedlings. 相似文献
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